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Network failures continue to plague datacenter operators as their symptoms
may not have direct correlation with where or why they occur. We introduce 007,
a lightweight, always-on diagnosis application that can find problematic links
and also pinpoint problems for each TCP connection. 007 is completely contained
within the end host. During its two month deployment in a tier-1 datacenter, it
detected every problem found by previously deployed monitoring tools while also
finding the sources of other problems previously undetected.
|
http://arxiv.org/abs/1802.07222v1
|
We demonstrated a Germanium-on-Silicon photodetector utilizing an asymmetric-Fabry-Perot resonator with 0.08 fF capacitance. The measurements at 1315.5 nm show 0.72 nA (3.40 nA) dark current, 0.93 A/W (0.96 A/W) responsivity, 36 Gb/s (38 Gb/s) operation at -1V (-2V) bias.
|
https://arxiv.org/abs/2401.03527v1
|
Sample average approximation (SAA) is a tractable approach for dealing with chance constrained programming, a challenging stochastic optimization problem. The constraint of SAA is characterized by the $0/1$ loss function which results in considerable complexities in devising numerical algorithms. Most existing methods have been devised based on reformulations of SAA, such as binary integer programming or relaxed problems. However, the development of viable methods to directly tackle SAA remains elusive, let alone providing theoretical guarantees. In this paper, we investigate a general $0/1$ constrained optimization, providing a new way to address SAA rather than its reformulations. Specifically, starting with deriving the Bouligand tangent and Fr$\acute{e}$chet normal cones of the $0/1$ constraint, we establish several optimality conditions. One of them can be equivalently expressed by a system of equations, enabling the development of a semismooth Newton-type algorithm. The algorithm demonstrates a locally superlinear or quadratic convergence rate under standard assumptions, along with nice numerical performance compared to several leading solvers.
|
https://arxiv.org/abs/2210.11889v4
|
The step function is one of the simplest and most natural activation functions for deep neural networks (DNNs). As it counts 1 for positive variables and 0 for others, its intrinsic characteristics (e.g., discontinuity and no viable information of subgradients) impede its development for several decades. Even if there is an impressive body of work on designing DNNs with continuous activation functions that can be deemed as surrogates of the step function, it is still in the possession of some advantageous properties, such as complete robustness to outliers and being capable of attaining the best learning-theoretic guarantee of predictive accuracy. Hence, in this paper, we aim to train DNNs with the step function used as an activation function (dubbed as 0/1 DNNs). We first reformulate 0/1 DNNs as an unconstrained optimization problem and then solve it by a block coordinate descend (BCD) method. Moreover, we acquire closed-form solutions for sub-problems of BCD as well as its convergence properties. Furthermore, we also integrate $\ell_{2,0}$-regularization into 0/1 DNN to accelerate the training process and compress the network scale. As a result, the proposed algorithm has a high performance on classifying MNIST and Fashion-MNIST datasets. As a result, the proposed algorithm has a desirable performance on classifying MNIST, FashionMNIST, Cifar10, and Cifar100 datasets.
|
https://arxiv.org/abs/2206.09379v2
|
We study pseudo-polynomial time algorithms for the fundamental \emph{0-1 Knapsack} problem. Recent research interest has focused on its fine-grained complexity with respect to the number of items $n$ and the \emph{maximum item weight} $w_{\max}$. Under $(\min,+)$-convolution hypothesis, 0-1 Knapsack does not have $O((n+w_{\max})^{2-\delta})$ time algorithms (Cygan-Mucha-W\k{e}grzycki-W\l{}odarczyk 2017 and K\"{u}nnemann-Paturi-Schneider 2017). On the upper bound side, currently the fastest algorithm runs in $\tilde O(n + w_{\max}^{12/5})$ time (Chen, Lian, Mao, and Zhang 2023), improving the earlier $O(n + w_{\max}^3)$-time algorithm by Polak, Rohwedder, and W\k{e}grzycki (2021). In this paper, we close this gap between the upper bound and the conditional lower bound (up to subpolynomial factors): - The 0-1 Knapsack problem has a deterministic algorithm in $O(n + w_{\max}^{2}\log^4w_{\max})$ time. Our algorithm combines and extends several recent structural results and algorithmic techniques from the literature on knapsack-type problems: - We generalize the "fine-grained proximity" technique of Chen, Lian, Mao, and Zhang (2023) derived from the additive-combinatorial results of Bringmann and Wellnitz (2021) on dense subset sums. This allows us to bound the support size of the useful partial solutions in the dynamic program. - To exploit the small support size, our main technical component is a vast extension of the "witness propagation" method, originally designed by Deng, Mao, and Zhong (2023) for speeding up dynamic programming in the easier unbounded knapsack settings. To extend this approach to our 0-1 setting, we use a novel pruning method, as well as the two-level color-coding of Bringmann (2017) and the SMAWK algorithm on tall matrices.
|
https://arxiv.org/abs/2308.04093v2
|
In a recent paper, the question of determining the fraction of binary trees that contain a fixed pattern known as the snowflake was posed. We show that this fraction goes to 1, providing two very different proofs: a purely combinatorial one that is quantitative and specific to this problem; and a proof using branching process techniques that is less explicit, but also much more general, as it applies to any fixed patterns and can be extended to other trees and networks. In particular, it follows immediately from our second proof that the fraction of $d$-ary trees (resp. level-$k$ networks) that contain a fixed $d$-ary tree (resp. level-$k$ network) tends to $1$ as the number of leaves grows.
|
https://arxiv.org/abs/2402.04499v2
|
We consider statistical models of estimation of a rank-one matrix (the spike) corrupted by an additive gaussian noise matrix in the sparse limit. In this limit the underlying hidden vector (that constructs the rank-one matrix) has a number of non-zero components that scales sub-linearly with the total dimension of the vector, and the signal strength tends to infinity at an appropriate speed. We prove explicit low-dimensional variational formulas for the asymptotic mutual information between the spike and the observed noisy matrix in suitable sparse limits. For Bernoulli and Bernoulli-Rademacher distributed vectors, and when the sparsity and signal strength satisfy an appropriate scaling relation, these formulas imply sharp 0-1 phase transitions for the asymptotic minimum mean-square-error. A similar phase transition was analyzed recently in the context of sparse high-dimensional linear regression (compressive sensing).
|
https://arxiv.org/abs/1911.05030v1
|
We propose that a simple, Lagrangian 2d $\mathcal{N}=(0, 2)$ duality
interface between the 3d $\mathcal{N}=2$ XYZ model and 3d $\mathcal{N}=2$ SQED
can be associated to the simplest triangulated 4-manifold: the 4-simplex. We
then begin to flesh out a dictionary between more general triangulated
4-manifolds with boundary and 2d $\mathcal{N}=(0, 2)$ interfaces. In
particular, we identify IR dualities of interfaces associated to local changes
of 4d triangulation, governed by the (3,3), (2,4), and (4,2) Pachner moves. We
check these dualities using supersymmetric half-indices. We also describe how
to produce stand-alone 2d theories (as opposed to interfaces) capturing the
geometry of 4-simplices and Pachner moves by making additional field-theoretic
choices, and find in this context that the Pachner moves recover abelian
$\mathcal{N}=(0,2)$ trialities of Gadde-Gukov-Putrov. Our work provides new,
explicit tools to explore the interplay between 2d dualities and 4-manifold
geometry that has been developed in recent years.
|
http://arxiv.org/abs/1905.05173v2
|
We introduce a class of (0,2) superconformal field theories based on hybrid
geometries, generalizing various known constructions. We develop techniques for
the computation of the complete massless spectrum when the theory can be
interpreted as determining a perturbative heterotic string compactification. We
provide evidence for surprising properties regarding RG flows and IR accidental
symmetries in (0,2) hybrid CFTs. We also study the conditions for embedding a
hybrid theory in a particular class of gauged linear sigma models. This
perspective suggests that our construction generates models which cannot be
realized or analyzed by previously known methods.
|
http://arxiv.org/abs/1712.04976v2
|
In this work we find the first examples of (0,2) mirror symmetry on compact non-K\"ahler complex manifolds. For this we follow Borisov's approach to mirror symmetry using vertex algebras and the chiral de Rham complex. Our examples of (0,2) mirrors are given by pairs of Hopf surfaces endowed with a Bismut-flat pluriclosed metric. Requiring that the geometry is homogeneous, we reduce the problem to the study of Killing spinors on a quadratic Lie algebra and the construction of embeddings of the $N=2$ superconformal vertex algebra in the superaffine vertex algebra, combined with topological T-duality.
|
https://arxiv.org/abs/2012.01851v3
|
Two-dimensional $\mathcal{N}=(0,4)$ supersymmetric quiver gauge theories are
realized as D3-brane box configurations (two dimensional intervals) which are
bounded by NS5-branes and intersect with D5-branes. The periodic brane
configuration is mapped to D1-D5-D5$'$ brane system at orbifold singularity via
T-duality. The matter content and interactions are encoded by the
$\mathcal{N}=(0,4)$ quiver diagrams which are determined by the brane
configurations. The Abelian gauge anomaly cancellation indicates the presence
of Fermi multiplets at the NS-NS$'$ junction. We also discuss the brane
construction of $\mathcal{N}=(0,4)$ supersymmetric boundary conditions in 3d
$\mathcal{N}=4$ gauge theories involving two-dimensional boundary degrees of
freedom that cancel gauge anomaly.
|
http://arxiv.org/abs/1811.09117v1
|
We study a class of two-dimensional ${\cal N}=(0, 4)$ quiver gauge theories
that flow to superconformal field theories. We find dualities for the
superconformal field theories similar to the 4d ${\cal N}=2$ theories of class
${\cal S}$, labelled by a Riemann surface ${\cal C}$. The dual descriptions
arise from various pair-of-pants decompositions, that involves an analog of the
$T_N$ theory. Especially, we find the superconformal index of such theories can
be written in terms of a topological field theory on ${\cal C}$. We interpret
this class of SCFTs as the ones coming from compactifying 6d ${\cal N}=(2, 0)$
theory on $\mathbb{CP}^1 \times {\cal C}$
|
http://arxiv.org/abs/1505.07110v2
|
We describe the projective superspace approach to supersymmetric models with off-shell $(0,4)$ supersymmetry in two dimensions. In addition to the usual superspace coordinates, projective superspace has extra bosonic variables -- one doublet for each $\text{SU}(2)$ in the R-symmetry $\text{SU}(2) \times \text{SU}(2)$ which are interpreted as homogeneous coordinates on $\mathbf{CP}^1 \times \mathbf{CP}^1$. The superfields are analytic in the $\mathbf{CP}^1$ coordinates and this analyticity plays an important role in our description. For instance, it leads to stringent constraints on the interactions one can write down for a given superfield content of the model. As an example, we describe in projective superspace Witten's ADHM sigma model -- a linear sigma model with non-derivative interactions whose target is $\mathbf{R}^4$ with a Yang-Mills instanton solution. The hyperk\"ahler nature of target space and the twistor description of instantons by Ward, and Atiyah, Hitchin, Drinfeld and Manin are natural outputs of our construction.
|
https://arxiv.org/abs/2303.14675v1
|
Electro-optic modulators transform electronic signals into the optical domain
and are critical components in modern telecommunication networks, RF photonics,
and emerging applications in quantum photonics and beam steering. All these
applications require integrated and voltage-efficient modulator solutions with
compact formfactors that are seamlessly integratable with Silicon photonics
platforms and feature near-CMOS material processing synergies. However,
existing integrated modulators are challenged to meet these requirements.
Conversely, emerging electro-optic materials heterogeneously integrated with Si
photonics open a new avenue for device engineering. Indium tin oxide (ITO) is
one such compelling material for heterogeneous integration in Si exhibiting
formidable electro-optic effect characterized by unity order index at
telecommunication frequencies. Here we overcome these limitations and
demonstrate a monolithically integrated ITO electro- optic modulator based on a
Mach Zehnder interferometer (MZI) featuring a high-performance half-wave
voltage and active device length product, VpL = 0.52 V-mm. We show, how that
the unity-strong index change enables a 30 micrometer-short pi-phase shifter
operating ITO in the index-dominated region away from the epsilon-bear-zero ENZ
point. This device experimentally confirms electrical phase shifting in ITO
enabling its use in multifaceted applications including dense on-chip
communication networks, nonlinearity for activation functions in photonic
neural networks, and phased array applications for LiDAR.
|
http://arxiv.org/abs/1809.03544v1
|
Near-term quantum computers will soon reach sizes that are challenging to directly simulate, even when employing the most powerful supercomputers. Yet, the ability to simulate these early devices using classical computers is crucial for calibration, validation, and benchmarking. In order to make use of the full potential of systems featuring multi- and many-core processors, we use automatic code generation and optimization of compute kernels, which also enables performance portability. We apply a scheduling algorithm to quantum supremacy circuits in order to reduce the required communication and simulate a 45-qubit circuit on the Cori II supercomputer using 8,192 nodes and 0.5 petabytes of memory. To our knowledge, this constitutes the largest quantum circuit simulation to this date. Our highly-tuned kernels in combination with the reduced communication requirements allow an improvement in time-to-solution over state-of-the-art simulations by more than an order of magnitude at every scale.
|
https://arxiv.org/abs/1704.01127v2
|
We explore a new class of AdS$_3$ solutions in massive type IIA supergravity preserving $\mathcal{N} = (0,6)$ supersymmetry and realising an $\mathfrak{osp}(6|2)$ superconformal algebra. These solutions exhibit an SO(6)-symmetric internal space constructed from a $\mathbb{CP}^3$, and are fully specified by a single cubic function controlling the fluxes and warping. We propose a brane box configuration underlying the solutions from which we construct a two-dimensional quiver gauge theory whose anomaly structure and central charge we analyse, and from which we can realise Seiberg-like dualities as large gauge transformations. The brane box configuration suggests an interpretation of the solutions as dual to surface defects within the ABJ(M) theory. Our findings provide a concrete setting for exploring holography beyond the ABJM vacuum. Remarkably, no explicit field theories are currently known to realise $\mathcal{N} = (0,6)$ supersymmetry in two dimensions, making our setup a promising and largely unexplored direction for field-theoretic investigations.
|
https://arxiv.org/abs/2504.20864v1
|
Electron tomography, as an important 3D imaging method, offers a powerful
method to probe the 3D structure of materials from the nano- to the
atomic-scale. However, as a grant challenge, radiation intolerance of the
nanoscale samples and the missing-wedge-induced information loss and artifacts
greatly hindered us from obtaining 3D atomic structures with high fidelity.
Here, for the first time, by combining generative adversarial models with
state-of-the-art network architectures, we demonstrate the resolution of
electron tomography can be improved to 0.71 angstrom which is the highest
three-dimensional imaging resolution that has been reported thus far. We also
show it is possible to recover the lost information and remove artifacts in the
reconstructed tomograms by only acquiring data from -50 to +50 degrees (44%
reduction of dosage compared to -90 to +90 degrees full tilt series). In
contrast to conventional methods, the deep learning model shows outstanding
performance for both macroscopic objects and atomic features solving the
long-standing dosage and missing-wedge problems in electron tomography. Our
work provides important guidance for the application of machine learning
methods to tomographic imaging and sheds light on its applications in other 3D
imaging techniques.
|
http://arxiv.org/abs/2003.12259v1
|
The Hilda asteroids are primitive bodies in resonance with Jupiter whose
origin and physical properties are not well understood. Current models posit
that these asteroids formed in the outer Solar System and were scattered along
with the Jupiter Trojans into their present-day positions during a chaotic
episode of dynamical restructuring. In order to explore the surface composition
of these enigmatic objects in comparison with an analogous study of Trojans
(Emery et al. 2011), we present new near-infrared spectra (0.7-2.5 $\mu$m) of
25 Hilda asteroids. No discernible absorption features are apparent in the
data. Synthesizing the bimodalities in optical color and infrared reflectivity
reported in previous studies, we classify 26 of the 28 Hildas in our spectral
sample into the so-called less-red and red sub-populations and find that the
two sub-populations have distinct average spectral shapes. Combining our
results with visible spectra, we find that Trojans and Hildas possess similar
overall spectral shapes, suggesting that the two minor body populations share a
common progenitor population. A more detailed examination reveals that while
the red Trojans and Hildas have nearly identical spectra, less-red Hildas are
systematically bluer in the visible and redder in the near-infrared than
less-red Trojans, indicating a putative broad, shallow absorption feature
between 0.5 and 1.0 $\mu$m. We argue that the less-red and red objects found in
both Hildas and Trojans represent two distinct surface chemistries and
attribute the small discrepancy between less-red Hildas and Trojans to the
difference in surface temperatures between the two regions.
|
http://arxiv.org/abs/1707.09064v1
|
Since the pioneering work of Ramsey, atom interferometers are employed for
precision metrology, in particular to measure time and to realize the second.
In a classical interferometer, an ensemble of atoms is prepared in one of the
two input states, whereas the second one is left empty. In this case, the
vacuum noise restricts the precision of the interferometer to the standard
quantum limit (SQL). Here, we propose and experimentally demonstrate a novel
clock configuration that surpasses the SQL by squeezing the vacuum in the empty
input state. We create a squeezed vacuum state containing an average of 0.75
atoms to improve the clock sensitivity of 10,000 atoms by 2.05 dB. The SQL
poses a significant limitation for today's microwave fountain clocks, which
serve as the main time reference. We evaluate the major technical limitations
and challenges for devising a next generation of fountain clocks based on
atomic squeezed vacuum.
|
http://arxiv.org/abs/1605.07754v1
|
High-speed physical key distribution is diligently pursued for secure communication. In this paper, we propose and experimentally demonstrate a scheme of high-speed key distribution using mode-shift keying chaos synchronization between two multi-longitudinal-mode Fabry-Perot lasers commonly driven by a super-luminescent diode. Legitimate users dynamically select one of the longitudinal modes according to private control codes to achieve mode-shift keying chaos synchronization. The two remote chaotic light waveforms are quantized to generate two raw random bit streams, and then those bits corresponding to chaos synchronization are sifted as shared keys by comparing the control codes. In this method, the transition time, i.e., the chaos synchronization recovery time is determined by the rising time of the control codes rather than the laser transition response time, so the key distribution rate is improved greatly. Our experiment achieved 0.75-Gbit/s key distribution rate with a bit error rate of 3.8*10-3 over 160-km fiber transmission with dispersion compensation. The entropy rate of the laser chaos is evaluated as 16 Gbit/s, which determines the ultimate final key rate together with key generation ratio. It is therefore believed that the method pays a way for Gbit/s physical key distribution.
|
https://arxiv.org/abs/2004.08586v3
|
Frequency comb and field-resolved broadband absorption spectroscopy are promising techniques for rapid, precise, and sensitive detection of short-lived atmospheric pollutants on-site. Enhancing detection sensitivity in absorption spectroscopy hinges on bright sources that cover molecular resonances and fast signal modulation techniques to implement lock-in detection schemes efficiently. Yb:YAG thin-disk lasers, combined with optical parametric oscillators (OPO), present a compelling solution to fulfill these requirements. In this work, we report on a bright OPO pumped by a Yb:YAG thin-disk Kerr-lens mode-locked oscillator delivering 2.8 W, 114 fs pulses at 2.06 {\mu}m with an averaged energy of 90 nJ. The OPO cavity operates at 30.9 MHz pulse repetition rates, the second harmonic of the pump cavity, allowing for broadband, efficient, and dispersion-free modulation of the OPO output pulses at 15.45 MHz rate. With 13% optical-to-optical conversion efficiency and a high-frequency intra-cavity modulation, this scalable scheme holds promise to advance the detection sensitivity and frontiers of field-resolved spectroscopic techniques.
|
https://arxiv.org/abs/2407.13371v1
|
An all-silica-fiber thulium-doped fiber laser emitting at 0.82 um on the transition from 3H4 to the ground state 3H6 outputs 105 W continuous-wave (CW) power and 555 W quasi-continuous-wave (QCW) instantaneous power with 0.96% duty cycle in 240-us rectangular pulses. The TDFL comprises a double-clad thulium-doped fiber (TDF) which is designed and fabricated in-house and is incorporated into an all-fiber cavity and cladding-pumped by five pigtailed diode lasers at 0.79 um. Co-lasing at 1.9 um counteracts population trapping in 3F4. The slope efficiency relative to absorbed pump power reaches 64% QCW and 77.5% CW. QCW, the beam quality M2 becomes 2.2 (beam parameter product BPP 0.57 mm mrad) and 2.45 (BPP 0.64) in orthogonal directions at ~250 W of instantaneous output power. Additionally, a modified QCW setup is continuously wavelength-tunable from 812 nm to 835 nm. We believe this is the first reported demonstration of high-power laser operation of the 3H4 to 3H6 transition in a TDF. Given also the simplicity and other attractions of an all-silica-fiber laser with direct-diode cladding-pumping, we believe our demonstration is valuable for applications ranging from laser machining of aluminum (benefitting from an absorption peak at 0.83 um) to scientific applications including strontium-based atomic clocks and cesium-based quantum metrology.
|
https://arxiv.org/abs/2505.09582v1
|
We present a framework for computational ghost imaging based on deep learning and customized pink noise speckle patterns. The deep neural network in this work, which can learn the sensing model and enhance image reconstruction quality, is trained merely by simulation. To demonstrate the sub-Nyquist level in our work, the conventional computational ghost imaging results, reconstructed imaging results using white noise and pink noise via deep learning are compared under multiple sampling rates at different noise conditions. We show that the proposed scheme can provide high-quality images with a sampling rate of 0.8% even when the object is outside the training dataset, and it is robust to noisy environments. This method is excellent for various applications, particularly those that require a low sampling rate, fast reconstruction efficiency, or experience strong noise interference.
|
https://arxiv.org/abs/2108.07673v1
|
We use QCD spectral sum rules (QSSR) and the factorization properties of
molecule and four-quark currents to estimate the masses and couplings of the 0+
and 1+ molecules and four-quark at N2LO of PT QCD. We include in the OPE the
contributions of non-perturbative condensates up to dimension-six. Within the
Laplace sum rules approach (LSR) and in the MS-scheme, we summarize our results
in Table 2, which agree within the errors with some of the observed XZ-like
molecules or/and four-quark. Couplings of these states to the currents are also
extracted. Our results are improvements of the LO ones in the existing
literature.
|
http://arxiv.org/abs/1801.09110v1
|
In this short note we prove an analogue of Auslander correspondence for exact dg categories whose $H^0$-category is $0$-Auslander in the sense of Gorsky--Nakaoka--Palu.
|
https://arxiv.org/abs/2306.15958v2
|
In this paper we investigate the 0-concordance classes of 2-knots in $S^4$,
an equivalence relation that is related to understanding smooth structures on
4-manifolds. Using Rochlin's invariant, and invariants arising from
Heegaard-Floer homology, we will prove that there are infinitely many
0-concordance classes of 2-knots.
|
http://arxiv.org/abs/1907.06524v1
|
In this paper we provide a new obstruction to 0-concordance of knotted
surfaces in $S^4$ in terms of Alexander ideals. We use this to prove the
existence of infinitely many linearly independent 0-concordance classes and to
provide the first proof that the submonoid of 2-knots is not a group. The main
result is that the Alexander ideal induces a homomorphism from the
0-concordance monoid $\mathscr{C}_0$ of oriented surface knots in $S^4$ to the
ideal class monoid of $\mathbb{Z}[t^{\pm1}]$. Consequently, any surface knot
with nonprincipal Alexander ideal is not 0-slice and in fact, not invertible in
$\mathscr{C}_0$. Many examples are given. We also characterize which ideals are
the ideals of surface knots, generalizing a theorem of Kinoshita, and
generalize the knot determinant to the case of nonprincipal ideals. Lastly, we
show that under a mild condition on the knot group, the peripheral subgroup of
a knotted surface is also a 0-concordance invariant.
|
http://arxiv.org/abs/1911.13112v1
|
Let $F$ be an infinite division ring, $V$ be a left $F$-vector space, $r>0$
be an integer. We study the structure of the representation of the linear group
$\mathrm{GL}_F(V)$ in the vector space of formal finite linear combinations of
$r$-dimensional vector subspaces of $V$ with coefficients in a field $K$. This
gives a series of natural examples of irreducible infinite-dimensional
representations of projective groups. These representations are non-smooth if
$F$ is locally compact and non-discrete.
|
http://arxiv.org/abs/1811.08675v3
|
Presence of coherent resonant tunneling in quantum dot (zero-dimensional) - quantum well (two-dimensional) heterostructure is necessary to explain the collective oscillations of average electrical polarization of excitonic dipoles over a macroscopically large area. This was measured using photo excited capacitance as a function of applied voltage bias. Resonant tunneling in this heterostructure definitely requires momentum space narrowing of charge carriers inside the quantum well and that of associated indirect excitons, which indicates bias dependent itinerant Bose-Einstein condensation of excitons. Observation of periodic variations in negative quantum capacitance points to in-plane coulomb correlations mediated by long range spatial ordering of indirect, dipolar excitons. Enhanced contrast of quantum interference beats of excitonic polarization waves even under white light and observed Rabi oscillations over a macroscopically large area also support the presence of density driven excitonic condensation having long range order. Periodic presence (absence) of splitting of excitonic peaks in photocapacitance spectra even demonstrate collective coupling (decoupling) between energy levels of the quantum well and quantum dots with applied biases, which can potentially be used for quantum gate operations. All these observations point to experimental control of macroscopically large, quantum state of a two-component Bose-Einstein condensate of excitons in this quantum dot - quantum well heterostructure. Therefore, in principle, millions of two-level excitonic qubits can be intertwined to fabricate large quantum registers using such hybrid heterostructure by controlling the local electric fields and also by varying photoexcitation intensities of overlapping light spots.
|
https://arxiv.org/abs/2107.13518v3
|
This note presents TopoMap, a novel dimensionality reduction technique which provides topological guarantees during the mapping process. In particular, TopoMap performs the mapping from a high-dimensional space to a visual space, while preserving the 0-dimensional persistence diagram of the Rips filtration of the high-dimensional data, ensuring that the filtrations generate the same connected components when applied to the original as well as projected data. The presented case studies show that the topological guarantee provided by TopoMap not only brings confidence to the visual analytic process but also can be used to assist in the assessment of other projection methods.
|
https://openreview.net/forum?id=zrDNDWjOGwH
|
We propose axioms for 0-dimensional ideal approximation theory and note that extriangulated categories satisfy these axioms.
|
https://arxiv.org/abs/2502.04665v1
|
Orbifold singularities of M-theory constitute the building blocks of a broad class of supersymmetric quantum field theories (SQFTs). In this paper we show how the local data of these geometries determines global data on the resulting higher symmetries of these systems. In particular, via a process of cutting and gluing, we show how local orbifold singularities encode the 0-form, 1-form and 2-group symmetries of the resulting SQFTs. Geometrically, this is obtained from the possible singularities which extend to the boundary of the non-compact geometry. The resulting category of boundary conditions then captures these symmetries, and is equivalently specified by the orbifold homology of the boundary geometry. We illustrate these general points in the context of a number of examples, including 5D superconformal field theories engineered via orbifold singularities, 5D gauge theories engineered via singular elliptically fibered Calabi-Yau threefolds, as well as 4D SQCD-like theories engineered via M-theory on non-compact $G_2$ spaces.
|
https://arxiv.org/abs/2203.10102v4
|
Motivated by the LHCb's new observation of structures in the $J/\psi$-pair
invariant mass spectrum, for which could be classified as possible
$cc\bar{c}\bar{c}$ tetraquark candidates, we systematically study $0^{+}$
fully-charmed tetraquark states through QCD sum rules. Making the development
of calculation techniques to fourfold heavy hadronic systems, four different
configuration currents with $0^{+}$ are considered and vacuum condensates up to
dimension $6$ are included in the operator product expansion (OPE). Finally,
mass values acquired for $0^{+}$ $cc\bar{c}\bar{c}$ tetraquark states agree
well with the experimental data of the broad structure, which supports that it
could be a $0^{+}$ fully-charmed tetraquark state.
|
http://arxiv.org/abs/2010.07719v1
|
In Digital Geometry, gaps are some basic portion of a digital object that a discrete ray can cross without intersecting any voxel of the object itself. Such a notion is quite important in combinatorial image analysis and it is strictly connected with some applications in fields as CAD and Computer graphics. In this paper we prove that the number of $0$-gaps of a $3$D digital curve can be expressed as a linear combination of the number of its $i$-cells (with $i = 0, \ldots, 3$).
|
https://arxiv.org/abs/2109.13341v1
|
We extend the notion of ascent-compatibility from symmetric groups to all Coxeter groups, thereby providing a type-independent framework for constructing families of modules of $0$-Hecke algebras. We apply this framework in type $B$ to give representation-theoretic interpretations of a number of noteworthy families of type-$B$ quasisymmetric functions. Next, we construct modules of the type-$B$ $0$-Hecke algebra corresponding to type-$B$ analogues of Schur functions and introduce a type-$B$ analogue of Schur $Q$-functions; we prove that these shifted domino functions expand positively in the type-$B$ peak functions. We define a type-$B$ analogue of the $0$-Hecke--Clifford algebra, and we use this to provide representation-theoretic interpretations for both the type-$B$ peak functions and the shifted domino functions. We consider the modules of this algebra induced from type-$B$ $0$-Hecke modules constructed via ascent-compatibility and prove a general formula, in terms of type-$B$ peak functions, for the type-$B$ quasisymmetric characteristics of the restrictions of these modules.
|
https://arxiv.org/abs/2404.04961v1
|
We introduce a new basis of quasisymmetric functions, the row-strict dual immaculate functions. We construct a cyclic, indecomposable 0-Hecke algebra module for these functions. Our row-strict immaculate functions are related to the dual immaculate functions of Berg-Bergeron-Saliola-Serrano-Zabrocki (2014-15) by the involution $\psi$ on the ring of quasisymmetric functions. We give an explicit description of the effect of $\psi$ on the associated 0-Hecke modules, via the poset induced by the 0-Hecke action on standard immaculate tableaux. This remarkable poset reveals other 0-Hecke submodules and quotient modules, often cyclic and indecomposable, notably for a row-strict analogue of the extended Schur functions studied in Assaf-Searles (2019). Like the dual immaculate function, the row-strict dual immaculate function is the generating function of a suitable set of tableaux, corresponding to a specific descent set. We give a complete combinatorial and representation-theoretic picture by constructing 0-Hecke modules for the remaining variations on descent sets, and showing that \emph{all} the possible variations for generating functions of tableaux occur as characteristics of the 0-Hecke modules determined by these descent sets.
|
https://arxiv.org/abs/2202.00708v3
|
Segmentation of moving objects in dynamic scenes is a key process in scene understanding for navigation tasks. Classical cameras suffer from motion blur in such scenarios rendering them effete. On the contrary, event cameras, because of their high temporal resolution and lack of motion blur, are tailor-made for this problem. We present an approach for monocular multi-motion segmentation, which combines bottom-up feature tracking and top-down motion compensation into a unified pipeline, which is the first of its kind to our knowledge. Using the events within a time-interval, our method segments the scene into multiple motions by splitting and merging. We further speed up our method by using the concept of motion propagation and cluster keyslices. The approach was successfully evaluated on both challenging real-world and synthetic scenarios from the EV-IMO, EED, and MOD datasets and outperformed the state-of-the-art detection rate by 12\%, achieving a new state-of-the-art average detection rate of 81.06%, 94.2% and 82.35% on the aforementioned datasets. To enable further research and systematic evaluation of multi-motion segmentation, we present and open-source a new dataset/benchmark called MOD++, which includes challenging sequences and extensive data stratification in-terms of camera and object motion, velocity magnitudes, direction, and rotational speeds.
|
https://arxiv.org/abs/2006.06158v2
|
We build a new spectrum of recursive models (SRM(T)) of a strongly minimal theory. This theory is non-disintegrated, flat, model complete, and in a language with a finite signature.
|
https://arxiv.org/abs/1908.09387v2
|
We introduce a method for isospin restoration in the calculation of nuclear
matrix elements (NME) for $0\nu\beta\beta$ and $2\nu\beta\beta$ decay within
the framework of interacting boson model (IBM-2). With this method, we
calculate NME for all processes of interest in $0\nu\beta^-\beta^-$,
$2\nu\beta^-\beta^-$, and in $0\nu\beta^+\beta^+$, $0\nu\beta^+ EC^+$, $R0\nu
ECEC$, $2\nu\beta^+\beta^+$, $2\nu\beta^+EC$, and $2\nu ECEC$. With this
method, the Fermi (F) matrix elements for $2\nu\beta\beta$ vanish, and those
for $0\nu\beta\beta$ are considerably reduced.
|
http://arxiv.org/abs/1506.08530v1
|
We consider a version of Left-Right Symmetric Model in which the scalar
sector consists of a Higgs bidoublet ($\Phi$) with $B-L=0$, Higgs doublets
($H_{L,R}$) with $B-L=1$ and a charged scalar ($\delta^+$) with $B-L=2$ leading
to radiatively generated Majorana masses for neutrinos and thereby, leads to
new physics contributions to neutrinoless double beta decay ($0\nu \beta
\beta$). We show that such a novel framework can be embedded in a non-SUSY
$SO(10)$ GUT leading to successful gauge coupling unification at around
$10^{16}$ GeV with the scale of left-right symmetry breaking around $10^{10}$
GeV. The model can also be extended to have left-right symmetry breaking at TeV
scale, enabling detection of $W_R, Z_R$ bosons in LHC and future collider
searches. In the context of neutrinoless double beta decay, this model can
saturate the present bound from GERDA and KamLAND-Zen experiments. Also, we
briefly explain how keV-MeV range RH neutrino arising from our model can
saturate various astrophysical and cosmological constraints and can be
considered as warm Dark Matter (DM) candidate to address various cosmological
issues. We also discuss on left-right theories with Higgs doublets without
having scalar bidoublet leading to fermion masses and mixings by inclusion of
vector like fermions.
|
http://arxiv.org/abs/1809.10577v2
|
Intimate relation between the Gamow-Teller part of the matrix element
$M^{0\nu}_\mathrm{GT}$ and the $2\nu\beta\beta$ closure matrix element
$M^{2\nu}_\mathrm{cl}$ is explained and explored. If the corresponding radial
dependence $C^{2\nu}_\mathrm{cl}(r)$ would be known, $M^{0\nu}$ corresponding
to any mechanism responsible for the $0\nu\beta\beta$ decay can be obtained as
a simple integral. However, the $M^{2\nu}_\mathrm{cl}$ values sensitively
depend on the properties of higher lying $1^+$ states in the intermediate
odd-odd nuclei. We show that the $\beta^-$ and $\beta^+$ amplitudes of such
states typically have opposite relative signs, and their contributions reduce
severally the $M^{2\nu}_\mathrm{cl}$ values. Vanishing values of
$M^{2\nu}_\mathrm{cl}$ are signs of a partial restoration of the spin-isospin
$\mathrm{SU}(4)$ symmetry. We suggest that demanding that
$M^{2\nu}_\mathrm{cl}$ = 0 is a sensible way, within the method of the
Quasi-particle Random Phase Approximation (QRPA), of determining the amount of
renormalization of isoscalar particle-particle interaction strength
$g^{T=0}_{pp}$. Using such prescription, the matrix elements $M^{0\nu}$ are
evaluated; their values are not very different ($\le$ 20\%) from the usual QRPA
values when $g^{T=0}_{pp}$ is related to the known $2\nu\beta\beta$ half-lives.
|
http://arxiv.org/abs/1808.05016v1
|
Let the Euclidean plane be simultaneously and independently endowed with a
Poisson point process and a Poisson line process, each of unit intensity.
Consider a triangle T whose vertices all belong to the point process. The
triangle is 0-pierced if no member of the line process intersects any side of
T. Our starting point is Ambartzumian's 1982 joint density for angles of T; our
exposition is elementary and raises several unanswered questions.
|
http://arxiv.org/abs/1804.01353v2
|
Two superconductors coupled by a weak link support an equilibrium Josephson
electrical current which depends on the phase difference $\varphi$ between the
superconducting condensates [1]. Yet, when a temperature gradient is imposed
across the junction, the Josephson effect manifests itself through a coherent
component of the heat current that flows oppositely to the thermal gradient for
$ \varphi <\pi/2$ [2-4]. The direction of both the Josephson charge and heat
currents can be inverted by adding a $\pi$ shift to $\varphi$. In the static
electrical case, this effect was obtained in a few systems, e.g. via a
ferromagnetic coupling [5,6] or a non-equilibrium distribution in the weak link
[7]. These structures opened new possibilities for superconducting quantum
logic [6,8] and ultralow power superconducting computers [9]. Here, we report
the first experimental realization of a thermal Josephson junction whose phase
bias can be controlled from $0$ to $\pi$. This is obtained thanks to a
superconducting quantum interferometer that allows to fully control the
direction of the coherent energy transfer through the junction [10]. This
possibility, joined to the completely superconducting nature of our system,
provides temperature modulations with unprecedented amplitude of $\sim$ 100 mK
and transfer coefficients exceeding 1 K per flux quantum at 25 mK. Then, this
quantum structure represents a fundamental step towards the realization of
caloritronic logic components, such as thermal transistors, switches and memory
devices [10,11]. These elements, combined with heat interferometers [3,4,12]
and diodes [13,14], would complete the thermal conversion of the most important
phase-coherent electronic devices and benefit cryogenic microcircuits requiring
energy management, such as quantum computing architectures and radiation
sensors.
|
http://arxiv.org/abs/1607.02428v3
|
We investigate experimentally the supercurrent in a clean carbon nanotube
quantum dot, close to orbital degeneracy, connected to superconducting leads in
a regime of strong competition between local electronic correlations and
superconducting proximity effect. For an odd occupancy of the dot and
intermediate coupling to the reservoir, the Kondo effect can develop in the
normal state and screen the local magnetic moment of the dot. This leads to
singlet-doublet transitions that strongly affect the Josephson effect in a
single-level quantum dot: the sign of the supercurrent changes from positive to
negative (0 to $\pi$-junction). In the regime of strongest competition between
the Kondo effect and proximity effect, meaning that the Kondo temperature
equals the superconducting gap, the magnetic state of the dot undergoes a first
order quantum transition induced by the superconducting phase difference across
the junction. This is revealed experimentally by anharmonic current-phase
relations. In addition, the very specific electronic configuration of clean
carbon nanotubes, with two nearly orbitally degenerated states, leads to
different physics depending whether only one or both quasi-degenerate upper
levels of the dots participate to transport, which is determined by their
occupancy and relative widths. When the transport of Cooper pairs takes place
through only one of these levels, we find that the phase diagram of the
phase-dependent 0-$\pi$ transition is a universal characteristic of a
discontinuous level-crossing quantum transition at zero temperature. In the
case were two levels participate to transport, the nanotube Josephson current
exhibits a continuous 0-$\pi$ transition, independent of the superconducting
phase, revealing a different physical mechanism of the transition.
|
http://arxiv.org/abs/1601.03878v1
|
In a quantum dot hybrid superconducting junction, the behavior of the
supercurrent is dominated by Coulomb blockade physics, which determines the
magnetic state of the dot. In particular, in a single level quantum dot singly
occupied, the sign of the supercurrent can be reversed, giving rise to a
pi-junction. This 0-pi transition, corresponding to a singlet-doublet
transition, is then driven by the gate voltage or by the superconducting phase
in the case of strong competition between the superconducting proximity effect
and Kondo correlations. In a two-level quantum dot, such as a clean carbon
nanotube, 0-pi transitions exist as well but, because more cotunneling
processes are allowed, are not necessarily associated to a magnetic state
transition of the dot. In this proceeding, after a review of 0-pi transitions
in Josephson junctions, we present measurements of current-phase relation in a
clean carbon nanotube quantum dot, in the single and two-level regimes. In the
single level regime, close to orbital degeneracy and in a regime of strong
competition between local electronic correlations and superconducting proximity
effect, we find that the phase diagram of the phase-dependent transition is a
universal characteristic of a discontinuous level-crossing quantum transition
at zero temperature. In the case where the two levels are involved, the
nanotube Josephson current exhibits a continuous 0-pi transition, independent
of the superconducting phase, revealing a different physical mechanism of the
transition.
|
http://arxiv.org/abs/1712.08372v1
|
Optical trapping is having ever-increasing impact in science $-$ particularly biophysics, photonics and most recently in quantum optomechanics $-$ owing to its superior capability for manipulating nanoscale structures and materials. However, essentially all experimental optical trapping studies in the optical dipole regime have, to date, been dominated by the interaction between a material's electric polarizability, $\alpha_{e}$, and the electric part of the incident electromagnetic field, and therefore described by electric field intensity gradient forces. Optical trapping based on optical magnetic light-matter interactions has not been experimentally addressed despite it's immediate extension of the boundaries of optical trapping research and applications. This paper addresses this long-standing deficiency through the realization of optical magnetic trapping of large index of refraction (i.e., Si) nanoparticles and also presents a formalism for quantitative understanding of the experimental findings. Our experimental optical trapping results require including optical magnetic polarizability, $\alpha_{m}$, and electric-magnetic scattering forces associated with the Photonic Hall effect that are qualitatively and quantitatively validated by Maxwell stress tensor calculations. Our findings bring new opportunities for nanoparticle manipulation, potentially relax the limitations Ashkin claimed based on the optical Earnshaw's theorem, motivate optical matter formation by optical magnetic interactions, and suggest new N-body effects and symmetry breaking to drive dynamics of optical matter systems.
|
https://arxiv.org/abs/2408.09707v1
|
A graceful labelling of a tree T = (V,E), where V is the set of vertices of the tree and E is its edge set, is a bijective function f from V to the set consisting of the numbers 0, 1, ... |E| inclusive, such that if edge uv is assigned the value |f(u)-f(v)| then the edge labels are distinct numbers of the set consisting of the numbers 1, 2, ..., |E| inclusive. A tree is said to be 0-roratable if for any of its vertices there is a graceful labelling that assigns the label 0 to that vertex. A rooted symmetric tree is a tree in which all vertices at the same level from root vertex have the same degree. It was known since 1979 that rooted symmetric trees are graceful and an algebraic definition of graceful labelling of this class of trees was found by the author. In this paper we prove that rooted symmetric trees with at most 3 levels (including root vertex) are 0-rotatable. We also prove that symmetric spider trees with leg length at most 3 and symmetric banana trees, both of which are classes of rooted symmetric trees with 4 levels, are 0-rotatable. Based on these results, we conjecture that all spiders are 0-rotatable and raise the more general question whether all symmetric rooted trees are 0-rotatable.
|
https://arxiv.org/abs/2312.16235v1
|
Here, we prove that $0-$shake slice knots are slice.
|
https://arxiv.org/abs/2012.11176v2
|
A proof that $0-$shake slice knots are slice.
|
https://arxiv.org/abs/2104.00247v2
|
One common method for stabilizing robots after a push is the Instantaneous Capture Point, however, this has the fundamental limitation of assuming constant height. Although there are several works for balancing bipedal robots including height variations in 2D, the amount of literature on 3D models is limited. There are optimization methods using variable Center of Pressure (CoP) and reaction force to the ground, although they do not provide the physical region where a robot can step and require a precomputation for the analysis. This work provides the necessary and sufficient conditions to maintain balance of the 3D Variable Height Inverted Pendulum (VHIP) with both, fixed and variable CoP. We also prove that the 3D VHIP with Fixed CoP is the same as its 2D version, and we generalize controllers working on the 2D VHIP to the 3D VHIP. We also show the generalization of the Divergent Component of Motion to the 3D VHIP and we provide an alternative motion decomposition for the analysis of height and CoP strategies independently. This allow us to generalize previous global feedback controllers done in the 2D VHIP to the 3D VHIP with a Variable CoP.
|
https://arxiv.org/abs/1912.06078v1
|
In order to investigate the possibility of the recently observed $X(5568)$
being a $0^{+}$ tetraquark state, we make an improvement to the study of the
related various configuration states in the framework of the QCD sum rules.
Particularly, to ensure the quality of the analysis, condensates up to
dimension $12$ are included to inspect the convergence of operator product
expansion (OPE) and improve the final results of the studied states. We note
that some condensate contributions could play an important role on the OPE
side. By releasing the rigid OPE convergence criterion, we arrive at the
numerical value $5.57^{+0.35}_{-0.23}~\mbox{GeV}$ for the scalar-scalar
diquark-antidiquark $0^{+}$ state, which agrees with the experimental data for
the $X(5568)$ and could support its interpretation in terms of a $0^{+}$
tetraquark state with the scalar-scalar configuration. The corresponding result
for the axial-axial current is calculated to be
$5.77^{+0.44}_{-0.33}~\mbox{GeV}$, which is still consistent with the mass of
$X(5568)$ in view of the uncertainty. The feasibility of $X(5568)$ being a
tetraquark state with the axial-axial configuration therefore cannot be
definitely excluded. For the pseudoscalar-pseudoscalar and the vector-vector
cases, their unsatisfactory OPE convergence make it difficult to find
reasonable work windows to extract the hadronic information.
|
http://arxiv.org/abs/1705.03741v2
|
In this paper we consider 0-th order pseudodifferential operators on the
circle. We show that inside any interval disjoint from critical values of the
principal symbol, the spectrum is absolutely continuous with possibly finitely
many embedded eigenvalues. We also give an example of embedded eigenvalues.
|
http://arxiv.org/abs/1909.06316v1
|
Here, we study the neutrinoless double-$\beta$ ($0\nu\beta\beta$) decay between the ground state and the first $2^+$ state of $^{76}\mbox{Ge} \rightarrow {}^{76}\mbox{Se}$, $^{82}\mbox{Se} \rightarrow{}^{82}\mbox{Kr}$, $^{130}\mbox{Te} \rightarrow {}^{130}\mbox{Xe}$ and $^{136}\mbox{Xe} \rightarrow {}^{136}\mbox{Ba}$ systems. The relevant nuclear matrix elements (NMEs) involved in the process are calculated within the formalism of the microscopic interacting boson model (IBM-2). The IBM-2 has been widely used to obtain predictions for nuclear observables, such as the spectrum, but also to explore the possible emergence of beyond-the-Standard Model effects in the weak interactions of nuclei. Our calculations are carried out by considering the exchange of a Majorana neutrino between two nucleons ($2N$-mechanism). In addition to NMEs, we calculate the associated leptonic phase-space factors (PSFs) using electron radial wave functions, which are obtained by solving numerically the Dirac equation of a screened Coulomb potential that takes into account finite nuclear size. By combining our IBM-2 results for the NMEs with those for the PSFs along with experimental half-life limits, we can set limits on the $\langle \lambda \rangle$ and $\langle \eta \rangle$ couplings of left-right (L-R) models.
|
https://arxiv.org/abs/2301.02007v1
|
We review our results in\,\cite{ANR22} for the masses and couplings of $T_{ccqq'}\, (J^P=0^+)$ states from (inverse) QCD Laplace sum rule (LSR), their ratios ${\cal R}$ and double ratio of sum rules (DRSR) within stability criteria and including Factorized Next-to-Leading Order (FNLO) Perturbative (PT) corrections and Lowest Order (LO) QCD condensates up to $\langle G^3 \rangle$. We show that combining ${\cal R}$ and DRSR can provide more precise results. Calibrated to the observed $X_c(3872)$ and $T^{1^+}_{cc}(3875)$, ${\cal R}$ combined with DRSR lead to a more precise prediction of $M_{T^{0^+}_{cc}}=3883(3)~\rm{MeV}$. In a similar way, calibrated to the new prediction of $T^{0^+}_{cc}$ ${\cal R} \oplus$DRSR lead to the improved mass predictions: $M_{T^{0^+}_{cc\bar{s}\bar{u}}}=3927(6)~\rm{MeV}$ and $M_{T^{0^+}_{cc\bar{s}\bar{s}}}=3993(11)~\rm{MeV}$. We extend our analysis to the bottom sector and compare our results with the ones from different LSR predictions and some other determinations (lattice, quark and potential models,...) in the literature.
|
https://arxiv.org/abs/2212.10184v1
|
The uncertainty in the nuclear matrix elements (NMEs) of $0\nu\beta\beta$ decay for $^{76}$Ge, $^{82}$Se, $^{128}$Te, $^{130}$Te, and $^{136}$Xe in the self-consistent quasiparticle random phase approximation (QRPA) method is investigated by using eighteen Skyrme interactions supplemented with either a volume- or surface-type of pairing interactions. The NMEs for the isotopes concerned (except $^{136}$Xe) are less sensitive to the particle-hole ($ph$) interactions, while strongly dependent on the employed isovector particle-particle ($pp$) pairing interactions even though the pairing strengths are optimized to the same pairing gap. The results indicate that a precise determination of the isovector $pp$ pairing interaction in the Skyrme energy density functional is of importance to reduce the uncertainty in the NMEs within the QRPA framework.
|
https://arxiv.org/abs/2302.04423v1
|
We develop the formalism for calculating the decay rate of neutrinoless double beta decay to the $2^+$ excited states within L-R symmetric model. We consider the effects from induced hadronic currents up to NLO. The QRPA method in a spherical basis is adopted for the nuclear many-body calculation and the corresponding nuclear matrix elements are given. Also, the phase space factors are obtained with numerical electron wave functions. Our results suggest that the nuclear matrix elements are nucleus dependent and they are generally smaller than that of the decay to the ground states. And finally, we give a naive analysis of how current experiment data constrains the L-R symmetric model.
|
https://arxiv.org/abs/2208.08595v2
|
Quantum states are usually fragile which makes quantum computation being not as stable as classical computation. Quantum correction codes can protect quantum states but need a large number of physical qubits to code a single logic qubit. Alternatively, the protection at the hardware level has been recently developed to maintain the coherence of the quantum information by using symmetries. However, it generally has to pay the expense of increasing the complexity of the quantum devices. In this work, we show that the protection at the hardware level can be approached without increasing the complexity of the devices. The interplay between the spin-orbit coupling and the Zeeman splitting in the semiconductor allows us to tune the Josephson coupling in terms of the spin degree of freedom of Cooper pairs, the hallmark of the superconducting spintronics. This leads to the implementation of the parity-protected 0-$\pi$ superconducting qubit with only one highly transparent superconductor-semiconductor Josephson junction, which makes our proposal immune from the various fabrication imperfections.
|
https://arxiv.org/abs/2110.07516v1
|
We demonstrate an approach that allows taking videos at very high-speeds of
over 100,000 frames per second (fps) by exploiting the fast sampling rate of
the standard rolling-shutter readout mechanism, common to most conventional
sensors, and a compressive-sampling acquisition scheme. Our approach is
directly applied to a conventional imaging system by the simple addition of a
diffuser to the pupil plane, randomly encoding the entire field-of-view to each
camera row, while maintaining diffraction-limited resolution. A short video is
reconstructed from a single camera frame via a compressed-sensing
reconstruction algorithm, exploiting inherent sparsity of the imaged scene.
|
http://arxiv.org/abs/2004.09614v1
|
Podcasts are a large and growing repository of spoken audio. As an audio format, podcasts are more varied in style and production type than broadcast news, contain more genres than typically studied in video data, and are more varied in style and format than previous corpora of conversations. When transcribed with automatic speech recognition they represent a noisy but fascinating collection of documents which can be studied through the lens of natural language processing, information retrieval, and linguistics. Paired with the audio files, they are also a resource for speech processing and the study of paralinguistic, sociolinguistic, and acoustic aspects of the domain. We introduce the Spotify Podcast Dataset, a new corpus of 100,000 podcasts. We demonstrate the complexity of the domain with a case study of two tasks: (1) passage search and (2) summarization. This is orders of magnitude larger than previous speech corpora used for search and summarization. Our results show that the size and variability of this corpus opens up new avenues for research.
|
https://aclanthology.org/2020.coling-main.519
|
Abstract: Modern electronic and photonic devices rely on single-crystalline thin film semiconductors for high performance and reproducibility. The emerging halide perovskites have extraordinary electronic and photonic properties and can be synthesized via low cost solution-based methods. They have been used in a variety of devices with performance approaching or over the devices based on conventional materials. However, their solution based growth method is intrinsically challenge to grow large scale single-crystalline thin film due to the random nucleation and isotropous growth of the crystal. Here, we report the growth of centimeter-scale perovskite single-crystalline thin films by controlling the nucleation density and growth rate of the crystal under a spatially confined growth condition. The hydrophobic treatment on substrates inhibits nucleation and accelerates the growth of single-crystalline thin film, providing enough space for initial nucleus growing up quickly without touching each other. Single-crystalline perovskite thin-film with an aspect ratio of 1000 (1 cm in side length, 10 μm in thickness) has been successfully grown. The low trap density and the high mobility of the as-grown thin film show a high crystallinity. The photodetector based on the perovskite thin film has achieved a gain ~ 10^4, benefitting from the short transit time of the carries due to the high mobility and thin thickness of the active layer. Our work opens up a new route to grow large scale perovskite single-crystalline thin films, providing a platform to develop high- performance devices.
Cite this article: Deng, YH., Yang, ZQ. & Ma, RM. Growth of centimeter-scale perovskite single-crystalline thin film via surface engineering. Nano Convergence 7, 25 (2020). https://doi.org/10.1186/s40580-020-00236-5
DOI: https://doi.org/10.1186/s40580-020-00236-5
|
https://link.springer.com/article/10.1186/s40580-020-00236-5#Fig1
|
Real-time operation of a software-defined, GPU-based optical receiver is demonstrated over a 100-span straight-line optical link. Performance of minimum-phase Kramers-Kronig 4-, 8-, 16-, 32-, and 64-QAM signals are evaluated at various distances.
|
https://arxiv.org/abs/2104.06311v1
|
We introduce a benchmark of 10,000 instances with heterogeneous characteristics for the capacitated vehicle routing problem. We also provide optimal solutions for almost all of them along with a generator to produce additional training and validation data. This benchmark aims to permit a more systematic comparison of machine learning based search algorithms on this important problem. We also emit recommendations regarding the correct use of this dataset.
|
https://openreview.net/forum?id=yHiMXKN6nTl
|
Subset selection from massive data with noised information is increasingly
popular for various applications. This problem is still highly challenging as
current methods are generally slow in speed and sensitive to outliers. To
address the above two issues, we propose an accelerated robust subset selection
(ARSS) method. Specifically in the subset selection area, this is the first
attempt to employ the $\ell_{p}(0<p\leq1)$-norm based measure for the
representation loss, preventing large errors from dominating our objective. As
a result, the robustness against outlier elements is greatly enhanced.
Actually, data size is generally much larger than feature length, i.e. $N\gg
L$. Based on this observation, we propose a speedup solver (via ALM and
equivalent derivations) to highly reduce the computational cost, theoretically
from $O(N^{4})$ to $O(N{}^{2}L)$. Extensive experiments on ten benchmark
datasets verify that our method not only outperforms state of the art methods,
but also runs 10,000+ times faster than the most related method.
|
http://arxiv.org/abs/1409.3660v4
|
The advent of the James Webb Space Telescope has revealed a wealth of new galaxies just a few hundred Myr after the Big Bang. Some of these galaxies exhibit unusual elemental abundances that are difficult to explain with stellar populations today. While Wolf-Rayet stars in multiple-burst populations, very massive or rapidly-rotating primordial stars, general relativistic explosions of metal-enriched supermassive stars, or the precursors of globular clusters can in principle account for the supersolar nitrogen to oxygen ratios in the galaxies GN-z11 and CEERS 1019, no known stars or supernovae can explain the far higher N/O ratio of 0.46 in GS 3073 at redshift $z =$ 5.55. Here we show that the extreme nitrogen abundances in GS 3073 can be produced by 1000 - 10,000 M$_{\odot}$ primordial (Pop III) stars. We find that these are the only candidates that can account for its large N/O ratios and its C/O and Ne/O ratios. GS 3073 is thus the first conclusive evidence in the fossil abundance record of the existence of supermassive Pop III stars at cosmic Dawn.
|
https://arxiv.org/abs/2502.04435v2
|
Recent advances in speech synthesis have enabled many useful applications like audio directions in Google Maps, screen readers, and automated content generation on platforms like TikTok. However, these systems are mostly dominated by voices sourced from data-rich geographies with personas representative of their source data. Although 3000 of the world's languages are domiciled in Africa, African voices and personas are under-represented in these systems. As speech synthesis becomes increasingly democratized, it is desirable to increase the representation of African English accents. We present Afro-TTS, the first pan-African accented English speech synthesis system able to generate speech in 86 African accents, with 1000 personas representing the rich phonological diversity across the continent for downstream application in Education, Public Health, and Automated Content Creation. Speaker interpolation retains naturalness and accentedness, enabling the creation of new voices.
|
https://arxiv.org/abs/2406.11727v2
|
We report the lowest frequency measurements of gamma-ray burst (GRB) 171205A with the upgraded Giant Metrewave Radio Telescope (uGMRT) covering a frequency range from 250--1450 MHz and a period of $4-937$ days. It is the first GRB afterglow detected at 250--500 MHz frequency range and the second brightest GRB detected with the uGMRT. Even though the GRB is observed for nearly 1000 days, there is no evidence of transition to non-relativistic regime. We also analyse the archival ${\it Chandra}$ X-ray data on day $\sim 70$ and day $\sim 200$. We also find no evidence of a jet break from the analysis of combined data. We fit synchrotron afterglow emission arising from a relativistic, isotropic, self-similar deceleration as well as from a shock-breakout of wide-angle cocoon. Our data also allow us to discern the nature and the density of the circumburst medium. We find that the density profile deviates from a standard constant density medium and suggests that the GRB exploded in a stratified wind like medium. Our analysis shows that the lowest frequency measurements covering the absorbed part of the light curves are critical to unravel the GRB environment. Our data combined with other published measurements indicate that the radio afterglow has contribution from two components: a weak, possibly slightly off-axis jet and a surrounding wider cocoon, consistent with the results of Izzo et al. (2019). The cocoon emission likely dominates at early epochs, whereas the jet starts to dominate at later epochs, resulting in flatter radio lightcurves.
|
https://arxiv.org/abs/2012.05166v1
|
Negotiations began 1n 1968 for a telescope facility at Perth Observatory for NASA's International Planetary Patrol Network. 1,000 days later the telescope saw first light. The facility bears no resemblance to other observatories. Inside a dome, the telescope sits on a 42 ft tall concrete pier with a wrap-around staircase and concrete legs. Surrounding forest is similar in height to the dome, the design of which is counter intuitive. This study investigated why, at the risk of compromising performance, there was a departure from standard design, and to to identify drivers for the decision making. Observatory visitors learn of a government architect, Tadeusz Andrzejaczek who made whimsical, successive increases to the height of the structure. Though designed in collaboration with Acting Government Astronomer, Bertrand Harris, it is improbable that a public servant architect would have such influence over a scientific installation. Vibration amelioration was met by designing massive strength and rigidity into the structure. Thermal expansion and wind stresses were reduced using features such as shade fins and protective walls, and ground thermal disturbance was addressed by simply making it tall. Seeing measurements were not a significant design consideration. The facility exists with its current floor height because of successive approvals for modification. The initial design was by Harris and requests for redesigns came from him but in close negotiation the Andrzejaczek who desired a structure of futuristic shape and proportions. Harris's designs were influenced by his personal English background and the Old Perth Observatory where he worked as an astronomer. Andrzejaczek's design was influenced by an observatory in his birth city, his alignment with contemporary designers and his artistic flair.
|
https://arxiv.org/abs/2008.05146v1
|
Strategies for ultrafast optical control of magnetism have been a topic of
intense research for several decades because of the potential impact in
technologies such as magnetic memory, spintronics, and quantum computation, as
well as the opportunities for non-linear optical control and modulation in
applications such as optical isolation and non-reciprocity. Here we report the
first experimental quantification of optically induced magnetization in
plasmonic Au nanoparticles due to the inverse Faraday effect (IFE). The induced
magnetic moment in nanoparticles is found to be ~1,000x larger than that
observed in bulk Au, and ~20x larger than the magnetic moment from optimized
magnetic nanoparticle colloids such as magnetite. Furthermore, the
magnetization and demagnetization kinetics are instantaneous within the
sub-picosecond time resolution of our study, supporting a mechanism of coherent
transfer of angular momentum from the circularly polarized excitation to the
orbital angular momentum of the electron gas.
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http://arxiv.org/abs/1904.11425v1
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4D Gaussian Splatting (4DGS) has recently gained considerable attention as a method for reconstructing dynamic scenes. Despite achieving superior quality, 4DGS typically requires substantial storage and suffers from slow rendering speed. In this work, we delve into these issues and identify two key sources of temporal redundancy. (Q1) \textbf{Short-Lifespan Gaussians}: 4DGS uses a large portion of Gaussians with short temporal span to represent scene dynamics, leading to an excessive number of Gaussians. (Q2) \textbf{Inactive Gaussians}: When rendering, only a small subset of Gaussians contributes to each frame. Despite this, all Gaussians are processed during rasterization, resulting in redundant computation overhead. To address these redundancies, we present \textbf{4DGS-1K}, which runs at over 1000 FPS on modern GPUs. For Q1, we introduce the Spatial-Temporal Variation Score, a new pruning criterion that effectively removes short-lifespan Gaussians while encouraging 4DGS to capture scene dynamics using Gaussians with longer temporal spans. For Q2, we store a mask for active Gaussians across consecutive frames, significantly reducing redundant computations in rendering. Compared to vanilla 4DGS, our method achieves a $41\times$ reduction in storage and $9\times$ faster rasterization speed on complex dynamic scenes, while maintaining comparable visual quality. Please see our project page at https://4DGS-1K.github.io.
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https://arxiv.org/abs/2503.16422v1
|
Capturing high frame rate and high dynamic range (HFR&HDR) color videos in high-speed scenes with conventional frame-based cameras is very challenging. The increasing frame rate is usually guaranteed by using shorter exposure time so that the captured video is severely interfered by noise. Alternating exposures could alleviate the noise issue but sacrifice frame rate due to involving long-exposure frames. The neuromorphic spiking camera records high-speed scenes of high dynamic range without colors using a completely different sensing mechanism and visual representation. We introduce a hybrid camera system composed of a spiking and an alternating-exposure RGB camera to capture HFR&HDR scenes with high fidelity. Our insight is to bring each camera's superiority into full play. The spike frames, with accurate fast motion information encoded, are first reconstructed for motion representation, from which the spike-based optical flows guide the recovery of missing temporal information for middle- and long-exposure RGB images while retaining their reliable color appearances. With the strong temporal constraint estimated from spike trains, both missing and distorted colors cross RGB frames are recovered to generate time-consistent and HFR color frames. We collect a new Spike-RGB dataset that contains 300 sequences of synthetic data and 20 groups of real-world data to demonstrate 1000 FPS HDR videos outperforming HDR video reconstruction methods and commercial high-speed cameras.
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http://openaccess.thecvf.com//content/CVPR2023/html/Chang_1000_FPS_HDR_Video_With_a_Spike-RGB_Hybrid_Camera_CVPR_2023_paper.html
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Scaling up self-supervised learning has driven breakthroughs in language and vision, yet comparable progress has remained elusive in reinforcement learning (RL). In this paper, we study building blocks for self-supervised RL that unlock substantial improvements in scalability, with network depth serving as a critical factor. Whereas most RL papers in recent years have relied on shallow architectures (around 2 - 5 layers), we demonstrate that increasing the depth up to 1024 layers can significantly boost performance. Our experiments are conducted in an unsupervised goal-conditioned setting, where no demonstrations or rewards are provided, so an agent must explore (from scratch) and learn how to maximize the likelihood of reaching commanded goals. Evaluated on simulated locomotion and manipulation tasks, our approach increases performance by $2\times$ - $50\times$. Increasing the model depth not only increases success rates but also qualitatively changes the behaviors learned.
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https://arxiv.org/abs/2503.14858v1
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In this paper we present a new approach for pupil segmentation. It can be computed and trained very efficiently, making it ideal for online use for high speed eye trackers as well as for energy saving pupil detection in mobile eye tracking. The approach is inspired by the BORE and CBF algorithms and generalizes the binary comparison by Haar features. Since these features are intrinsically very susceptible to noise and fluctuating light conditions, we combine them with conditional pupil shape probabilities. In addition, we also rank each feature according to its importance in determining the pupil shape. Another advantage of our method is the use of statistical learning, which is very efficient and can even be used online. https://atreus.informatik.uni-tuebingen.de/seafile/d/8e2ab8c3fdd444e1a135/?p=%2FStatsPupil&mode=list
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https://arxiv.org/abs/2102.01921v1
|
In digital cameras, we find a major limitation: the image and video form inherited from a film camera obstructs it from capturing the rapidly changing photonic world. Here, we present vidar, a bit sequence array where each bit represents whether the accumulation of photons has reached a threshold, to record and reconstruct the scene radiance at any moment. By employing only consumer-level CMOS sensors and integrated circuits, we have developed a vidar camera that is 1,000x faster than conventional cameras. By treating vidar as spike trains in biological vision, we have further developed a spiking neural network-based machine vision system that combines the speed of the machine and the mechanism of biological vision, achieving high-speed object detection and tracking 1,000x faster than human vision. We demonstrate the utility of the vidar camera and the super vision system in an assistant referee and target pointing system. Our study is expected to fundamentally revolutionize the image and video concepts and related industries, including photography, movies, and visual media, and to unseal a new spiking neural network-enabled speed-free machine vision era.
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https://arxiv.org/abs/2201.09302v1
|
Scenario generation is one of the essential steps in scenario-based testing and, therefore, a significant part of the verification and validation of driver assistance functions and autonomous driving systems. However, the term scenario generation is used for many different methods, e.g., extraction of scenarios from naturalistic driving data or variation of scenario parameters. This survey aims to give a systematic overview of different approaches, establish different categories of scenario acquisition and generation, and show that each group of methods has typical input and output types. It shows that although the term is often used throughout literature, the evaluated methods use different inputs and the resulting scenarios differ in abstraction level and from a systematical point of view. Additionally, recent research and literature examples are given to underline this categorization.
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https://arxiv.org/abs/2304.10850v1
|
A deep learning model capable of solving any Sudoku grid (so far).
The model uses the Sudoku grid symmetry and it iteratively solves the grid filling digit step by step. A trial-and-error algorithm is also used if the model gets stuck on a step.
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https://www.linkedin.com/posts/sebastien-guissart_you-didnt-expect-it-but-here-it-is-after-activity-7281942649626877952-27Pe?utm_source=share&utm_medium=member_desktop
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The recent development of reasoning language models (RLMs) represents a novel evolution in large language models. In particular, the recent release of DeepSeek-R1 has generated widespread social impact and sparked enthusiasm in the research community for exploring the explicit reasoning paradigm of language models. However, the implementation details of the released models have not been fully open-sourced by DeepSeek, including DeepSeek-R1-Zero, DeepSeek-R1, and the distilled small models. As a result, many replication studies have emerged aiming to reproduce the strong performance achieved by DeepSeek-R1, reaching comparable performance through similar training procedures and fully open-source data resources. These works have investigated feasible strategies for supervised fine-tuning (SFT) and reinforcement learning from verifiable rewards (RLVR), focusing on data preparation and method design, yielding various valuable insights. In this report, we provide a summary of recent replication studies to inspire future research. We primarily focus on SFT and RLVR as two main directions, introducing the details for data construction, method design and training procedure of current replication studies. Moreover, we conclude key findings from the implementation details and experimental results reported by these studies, anticipating to inspire future research. We also discuss additional techniques of enhancing RLMs, highlighting the potential of expanding the application scope of these models, and discussing the challenges in development. By this survey, we aim to help researchers and developers of RLMs stay updated with the latest advancements, and seek to inspire new ideas to further enhance RLMs.
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https://arxiv.org/abs/2505.00551v3
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Effective driving style analysis is critical to developing human-centered intelligent driving systems that consider drivers' preferences. However, the approaches and conclusions of most related studies are diverse and inconsistent because no unified datasets tagged with driving styles exist as a reliable benchmark. The absence of explicit driving style labels makes verifying different approaches and algorithms difficult. This paper provides a new benchmark by constructing a natural dataset of Driving Style (100-DrivingStyle) tagged with the subjective evaluation of 100 drivers' driving styles. In this dataset, the subjective quantification of each driver's driving style is from themselves and an expert according to the Likert-scale questionnaire. The testing routes are selected to cover various driving scenarios, including highways, urban, highway ramps, and signalized traffic. The collected driving data consists of lateral and longitudinal manipulation information, including steering angle, steering speed, lateral acceleration, throttle position, throttle rate, brake pressure, etc. This dataset is the first to provide detailed manipulation data with driving-style tags, and we demonstrate its benchmark function using six classifiers. The 100-DrivingStyle dataset is available via https://github.com/chaopengzhang/100-DrivingStyle-Dataset
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https://arxiv.org/abs/2406.07894v1
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The issue of hallucinations in large language models (LLMs) remains a critical barrier to the adoption of AI in enterprise and other high-stakes applications. Despite advancements in retrieval-augmented generation (RAG) systems, current state-of-the-art methods fail to achieve more than 80% accuracy in generating faithful and factually correct outputs, even when provided with relevant and accurate context. In this work, we introduce Acurai, a novel systematic approach that achieves 100% hallucination-free responses in LLMs by reformatting queries and context data prior to input. Leveraging a deep understanding of LLM internal representations, the importance of noun-phrase dominance, and the role of discrete functional units (DFUs), Acurai ensures alignment between input context and generated output. We validate this method using the RAGTruth corpus, demonstrating its ability to eliminate 100% hallucinations for both GPT-4 and GPT-3.5 Turbo. Acurai sets a new standard for achieving consistent, accurate, and faithful AI responses, marking a significant step forward in the development of trustworthy AI systems.
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https://arxiv.org/abs/2412.05223v2
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In this paper, we demonstrate the communication capabilities of light-fidelity (LiFi) systems based on highbrightness and high-bandwidth integrated laser-based sources in a surface mount device (SMD) packaging platform. The laserbased source is able to deliver 450 lumens of white light illumination and the resultant light brightness is over 1000 cd mm2. It is demonstrated that a wavelength division multiplexing (WDM) LiFi system with ten parallel channels is able to deliver over 100 Gbps data rate with the assistance of Volterra filter-based nonlinear equalisers. In addition, an aggregated transmission data rate of 4.8 Gbps has been achieved over a link distance of 500 m with the same type of SMD light source. This work demonstrates the scalability of LiFi systems that employ laserbased light sources, particularly in their capacity to enable highspeed short range, as well as long-range data transmission.
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https://arxiv.org/abs/2402.16144v1
|
Emerging communication and cryptography applications call for reliable, fast, unpredictable random number generators. Quantum random number generation (QRNG) allows for the creation of truly unpredictable numbers thanks to the inherent randomness available in quantum mechanics. A popular approach is using the quantum vacuum state to generate random numbers. While convenient, this approach was generally limited in speed compared to other schemes. Here, through custom co-design of opto-electronic integrated circuits and side-information reduction by digital filtering, we experimentally demonstrated an ultrafast generation rate of 100 Gbps, setting a new record for vacuum-based quantum random number generation by one order of magnitude. Furthermore, our experimental demonstrations are well supported by an upgraded device-dependent framework that is secure against both classical and quantum side-information and that also properly considers the non-linearity in the digitization process. This ultrafast secure random number generator in the chip-scale platform holds promise for next generation communication and cryptography applications.
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https://arxiv.org/abs/2209.04339v2
|
We demonstrated for the first time quantum-safe high-speed 100 Gbps site-to-site IPsec tunnels secured using Quantum Key Distribution (QKD) technology. The demonstration was conducted between two JPMorgan Chase Data Centers (DCs) in an air-gapped environment over 46 km of deployed telecom fiber across Singapore achieving 45 days of continuous operation. Two different Virtual Private Network (VPN) tunnel configurations were tested: (1) a QKD-secured VPN tunnel configuration with a maximum throughput of 80 Gbps and (2) a multi-VPN tunnel configuration exhibiting 12 QKD-secured VPN tunnels with a throughput of 8.39 Gbps per tunnel resulting in an aggregated throughput of 99.62 Gbps for all tunnels. For the QKD system performance, we achieved an average Secret Key Rate (SKR) of 7.4 kbps (about 29 AES-256 keys per second), an average Quantum Bit Error Rate (QBER) of 0.8% and an average visibility of 98.6%. We utilized the ETSI-QKD-014 REST-based Application Programming Interface (API) to exchange the QKD generated keys between the key management server in the QKD system and the next-generation firewalls in order to encrypt and decrypt the data. The data was encrypted by the quantum-safe keys using the AES-256-GCM cipher suite with a key refresh rate of 120 seconds without affecting the VPN tunnel connectivity and performance
|
https://arxiv.org/abs/2405.04415v1
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Demands on Field-Programmable Gate Array (FPGA) data transport have been increasing over the years as frame sizes and refresh rates increase. As the bandwidths requirements increase the ability to implement data transport protocol layers using "soft" programmable logic becomes harder and start to require harden IP blocks implementation. To reduce the number of physical links and interconnects, it is common for data acquisition systems to require interleaving of streams on the same link (e.g. streaming data and streaming register access). This paper presents a way to leverage existing FPGA harden IP blocks to achieve a robust, low latency 100 Gb/s point-to-point link with minimal programmable logic overhead geared towards the needs of data acquisition systems with interleaved streaming requirements.
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https://arxiv.org/abs/2203.15671v3
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In this paper, we experimentally demonstrate that a silicon dual-drive
Mach-Zehnder modulator (DD-MZM) has great potential for next-generation data
center interconnections (DCIs). For intra-data center interconnections, 120
Gb/s Nyquist 4-ary pulse amplitude modulation (PAM-4) signal is successfully
generated with a silicon DD-MZM operating at C-band and transmitted over 2 km
standard single-mode fiber (SSMF) with a bit error rate (BER) of 5.55x10-4. For
inter-data center interconnections, single sideband (SSB) modulation is chosen
to avoid power fading caused by fiber chromatic dispersion and square-law
detection. We report the generation and transmission of 112 Gb/s Nyquist SSB
PAM-4 signal by using the same silicon DD-MZM and Kramers-Kronig (KK) direct
detection. A two-tap digital post filter and maximum likelihood sequence
detection (MLSD) are applied to compensate for the limited system bandwidth.
After 80 km SSMF transmission, the BER is 2.46x10-3 that is below the 7% HD-FEC
threshold of 3.8x10-3. To the best of our knowledge, our work reports the
highest single-lane bitrate of 80 km SSB transmission based on a silicon
DD-MZM. Our study also shows the feasibility of silicon photonic modulator for
DCI applications in the future.
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http://arxiv.org/abs/1811.11096v1
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An integrated hybrid thin-film lithium niobate (TFLN) electro-optic Mach-Zehnder modulator (MZM) is shown at near-infrared wavelengths. The design uses TFLN bonded to planarized silicon nitride waveguide circuits, and does not require etching or patterning of TFLN. The push-pull MZM achieves a half-wave voltage length product ($V_\pi L$) of 0.8 V$.$cm at 784 nm. MZM devices with 0.4 cm and 0.8 cm modulation length show a broadband electro-optic response with a 3 dB bandwidth beyond 100 GHz, with the latter showing a bandwidth to half-wave voltage ratio of 100 GHz/V.
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https://arxiv.org/abs/2211.13348v1
|
Electro-optic modulators provide a key function in optical transceivers and increasingly in photonic programmable Application Specific Integrated Circuits (ASICs) for machine learning and signal processing. However, both foundry ready silicon based modulators and conventional material based devices utilizing Lithium niobate fall short in simultaneously providing high chip packaging density and fast speed. Current driven ITO based modulators have the potential to achieve both enabled by efficient light matter interactions. Here, we introduce micrometer compact Mach Zehnder Interferometer (MZI) based modulators capable of exceeding 100 GHz switching rates. Integrating ITO thin films atop a photonic waveguide, spectrally broadband, and compact MZI phase shifter. Remarkably, this allows integrating more than 3500 of these modulators within the same chip area as only one single silicon MZI modulator. The modulator design introduced here features a holistic photonic, electronic, and RF-based optimization and includes an asymmetric MZI tuning step to optimize the Extinction Ratio (ER) to Insertion Loss (IL) and dielectric thickness sweep to balance the tradeoffs between ER and speed. Driven by CMOS compatible bias voltage levels, this device is the first to address next generation modulator demands for processors of the machine intelligence revolution, in addition to the edge and cloud computing demands as well as optical transceivers alike.
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https://arxiv.org/abs/2112.10926v2
|
Predicting the performance of LLMs on individual task instances is essential to ensure their reliability in high-stakes applications. To do so, a possibility is to evaluate the considered LLM on a set of task instances and train an assessor to predict its performance based on features of the instances. However, this approach requires evaluating each new LLM on a sufficiently large set of task instances to train an assessor specific to it. In this work, we leverage the evaluation results of previously tested LLMs to reduce the number of evaluations required to predict the performance of a new LLM. In practice, we propose to test the new LLM on a small set of reference instances and train a generic assessor which predicts the performance of the LLM on an instance based on the performance of the former on the reference set and features of the instance of interest. We conduct empirical studies on HELM-Lite and KindsOfReasoning, a collection of existing reasoning datasets that we introduce, where we evaluate all instruction-fine-tuned OpenAI models until the January 2024 version of GPT4. When predicting performance on instances with the same distribution as those used to train the generic assessor, we find this achieves performance comparable to the LLM-specific assessors trained on the full set of instances. Additionally, we find that randomly selecting the reference instances performs as well as some advanced selection methods we tested. For out of distribution, however, no clear winner emerges and the overall performance is worse, suggesting that the inherent predictability of LLMs is low.
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https://arxiv.org/abs/2409.03563v1
|
Pre-training is notoriously compute-intensive and academic researchers are notoriously under-resourced. It is, therefore, commonly assumed that academics can't pre-train models. In this paper, we seek to clarify this assumption. We first survey academic researchers to learn about their available compute and then empirically measure the time to replicate models on such resources. We introduce a benchmark to measure the time to pre-train models on given GPUs and also identify ideal settings for maximizing training speed. We run our benchmark on a range of models and academic GPUs, spending 2,000 GPU-hours on our experiments. Our results reveal a brighter picture for academic pre-training: for example, although Pythia-1B was originally trained on 64 GPUs for 3 days, we find it is also possible to replicate this model (with the same hyper-parameters) in 3x fewer GPU-days: i.e. on 4 GPUs in 18 days. We conclude with a cost-benefit analysis to help clarify the trade-offs between price and pre-training time. We believe our benchmark will help academic researchers conduct experiments that require training larger models on more data. We fully release our codebase at: https://github.com/apoorvkh/academic-pretraining.
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https://arxiv.org/abs/2410.23261v1
|
A target using a paisley pattern generates 100-kT-level magnetic fields. Laser irradiation induces local charge separation on the target, which creates surface currents along the concave surface, generating a magnetic field. For a laser intensity of $10^{21}$ W/cm$^2$, the target generates a 150-kT magnetic field. We developed a simple model to describe the magnetic field as a function of laser intensity and target radius. A double paisley configuration extends the lifetime of the magnetic field to the picosecond scale. The paisley design generates comparable results even if it is simplified. Thus, it is a robust and modular target suitable for magnetic field applications such as 100-kT magnetic field generation and magnetic reconnection.
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https://arxiv.org/abs/2202.00193v1
|
Long-context capability is considered one of the most important abilities of LLMs, as a truly long context-capable LLM enables users to effortlessly process many originally exhausting tasks -- e.g., digesting a long-form document to find answers vs. directly asking an LLM about it. However, existing real-task-based long-context evaluation benchmarks have two major shortcomings. First, benchmarks like LongBench often do not provide proper metrics to separate long-context performance from the model's baseline ability, making cross-model comparison unclear. Second, such benchmarks are usually constructed with fixed input lengths, which limits their applicability across different models and fails to reveal when a model begins to break down. To address these issues, we introduce a length-controllable long-context benchmark and a novel metric that disentangles baseline knowledge from true long-context capabilities. Experiments demonstrate the superiority of our approach in effectively evaluating LLMs.
|
https://arxiv.org/abs/2505.19293v1
|
An efficient error reconciliation scheme is important for post-processing of
quantum key distribution (QKD). Recently, a multi-matrix low-density
parity-check codes based reconciliation algorithm which can provide remarkable
perspectives for high efficiency information reconciliation was proposed. This
paper concerns the improvement of reconciliation performance. Multi-matrix
algorithm is implemented and optimized on the graphics processing unit (GPU) to
obtain high reconciliation throughput. Experimental results indicate that
GPU-based algorithm can highly improve reconciliation throughput to an average
85.67 Mbps and a maximum 102.084 Mbps with typical code rate and efficiency.
This is the best performance of reconciliation on GPU platform to our
knowledge.
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http://arxiv.org/abs/2001.07979v1
|
Metrics can be used by businesses to make more objective decisions based on data. Software startups in particular are characterized by the uncertain or even chaotic nature of the contexts in which they operate. Using data in the form of metrics can help software startups to make the right decisions amidst uncertainty and limited resources. However, whereas conventional business metrics and software metrics have been studied in the past, metrics in the spe-cific context of software startup are not widely covered within academic literature. To promote research in this area and to create a starting point for it, we have conducted a multi-vocal literature review focusing on practitioner literature in order to compile a list of metrics used by software startups. Said list is intended to serve as a basis for further research in the area, as the metrics in it are based on suggestions made by practitioners and not empirically verified.
|
https://arxiv.org/abs/1901.04819v1
|
Based on the dual-chirped optical parametric amplification and type-I BiB$_3$O$_6$(BiBO) crystals, the generation of $>$100 mJ, 10.4 fs, 10 Hz, carrier-to-envelope phase (CEP)-stable laser pulses, which are centered at 1.7 $\mu$m, is demonstrated; it produces a peak power of 10 TW. CEP-dependent high harmonic generation is implemented to confirm the sub-two-cycle pulse duration and CEP stabilization of infrared (IR) laser pulses. As far as we know, the obtained pulse energy and peak power represent the highest values for sub-two-cycle CEP-stable IR optical parametric amplification. Additionally, the prospects of achieving high-energy water window isolated attosecond pulses via our developed laser source are discussed.
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https://arxiv.org/abs/2202.03658v2
|
A scintillating bolometer technology based on $^{100}$Mo-enriched lithium
molybdate (Li$_2$$^{100}$MoO$_4$) crystals has been developed by LUMINEU to
search for neutrinoless double-beta ($0\nu 2\beta$) decay of $^{100}$Mo. The
results of several low temperature tests at underground environments have
proved the reproducibility of high detector performance and crystal
radiopurity: in particular $\sim$5--6~keV FWHM energy resolution and at least
9$\sigma$ rejection of $\alpha$'s in the vicinity of the $0\nu 2\beta$ decay of
$^{100}$Mo (3034 keV) and below 10~$\mu$Bq/kg bulk activity of $^{228}$Th and
$^{226}$Ra. A modest acquired exposure (0.1~kg$\times$yr) is a limiting factor
of the LUMINEU experiment sensitivity to the $0\nu 2\beta$ decay half-life of
$^{100}$Mo ($T_{1/2}$ $\geq$ 0.7$\times$10$^{23}$ yr at 90\% C.L.), however the
two-neutrino $2\beta$ decay has been measured with the best up to-date
accuracy, $T_{1/2}$ = $\left[6.92 \pm 0.06(\mathrm{stat.}) \pm
0.36(\mathrm{syst.})\right] \times 10^{18}$ yr. The applicability of the
LUMINEU technology for a tonne-scale $0\nu 2\beta$ decay bolometric project
CUPID is going to be demonstrated by the CUPID-0/Mo experiment with $\sim$5~kg
of $^{100}$Mo embedded in forty 0.2~kg Li$_2$$^{100}$MoO$_4$ scintillating
bolometers. A first phase of the experiment with twenty Li$_2$$^{100}$MoO$_4$
detectors is in preparation at the Modane underground laboratory (France) to
start by the end of 2017.
|
http://arxiv.org/abs/1709.07846v1
|
As a consequence of their work on average Selmer ranks of elliptic curves with marked points, Bhargava and Ho proved that $100\%$ of elliptic curves over $\mathbb{Q}$ with an additional marked point have positive rank. In this note we provide an alternate proof which extends the result to global fields of characteristic not two or three.
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https://arxiv.org/abs/2504.01965v1
|
We study the universal family of odd hyperelliptic curves of genus $g \geq 1$ over $\mathbb{Q}$. We relate the heights of $\mathbb{Q}$-points of Jacobians of curves in this family to the reduction theory of the representation of $\mathrm{SO}_{2g+1}$ on self-adjoint $(2g + 1) \times(2g + 1)$-matrices. Using this theory, we show that in a density 1 subset, the Jacobians of these curves have no nontrivial rational points of small height.
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https://arxiv.org/abs/2405.10224v1
|
We consider a specific family of analytic functions $g_{\alpha,T}(s)$, satisfying certain functional equations and approximating to linear combinations of the Riemann zeta-function and its derivatives of the form $c_0\zeta(s)+c_1\frac{\zeta'(s)}{\log T}+c_2\frac{\zeta''(s)}{(\log T)^2}+\dots+c_{K}\frac{\zeta^{(K)}(s)}{(\log T)^{K}}$. We also consider specific mollifiers of the form $M(s)D(s)$ for these linear combinations, where $M(s)$ is the classical mollifier, that is, a short Dirichlet polynomial for $1/\zeta(s)$, and the Dirichlet polynomial $D(s)$ is also short but with large and irregular Dirichlet coefficients, and arises from substitution for $w$, in Runge's complex approximation polynomial for $f(w)=\frac1{c_0+w}$, of the Selberg approximation for $\frac{c_1}{\log T}\frac{\zeta'}{\zeta}(s)+\frac{c_2}{(\log T)^2}\frac{\zeta''}{\zeta}(s)+\dots+\frac{c_{K}}{(\log T)^{K}}\frac{\zeta^{(K)}}{\zeta}(s)$ (analogous to Selberg's classical approximation for $\frac{\zeta'}{\zeta}(s)$). Exploiting the functional equations previously mentioned (concerning translation of the variable $s$), together with the mean-square asymptotics of the Levinson-Conrey method and the Selberg approximation theory (with some additional results) we show that almost all of the zeros of the Riemann zeta-function are on the critical line.
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https://arxiv.org/abs/1805.07741v6
|
Throughout this manuscript the zeros are counted with multiplicity. We denote by $N(T)$ the number of zeros $\rho$ of $\zeta(s)$ in the critical strip upto height $T$ where $T>3$ is not an ordinate of zero of $\zeta(s)$. Denote by $N_0(T)$ the number of zeros $\rho$ of $\zeta(s)$ on the critical line upto height $T$. We first show that there exists $\epsilon_0>0$ such that $\xi(s)$ has no zeros on the boundary of a small rectangle $R_\epsilon$ defined as $R_\epsilon=\{\sigma+it\in\mathbb{C}\mid \frac{1}{2}-\epsilon\leq \sigma\leq \frac{1}{2}+\epsilon,\ 0\leq t\leq T\}$ whenever $0<\epsilon<\epsilon_0$. Secondly if $N_\epsilon(T)$ is the number of zeros $\rho$ of $\zeta(s)$ inside the rectangle $R_\epsilon$ then we prove that $N_\epsilon (T)=N_0(T)$ for $\epsilon$ sufficiently small depending on the height $T$. We use the Littlewood's lemma on the rectangle $R_\epsilon$ along with the Hadamard product of $\xi(s)$ and the asymptotic for the logarithmic derivative of $\zeta(s)$ to prove that as $T\to \infty$, $$N_0(T)=\frac{T}{2\pi}\log\left(\frac{T}{2\pi}\right)-\frac{T}{2\pi}+\mathcal{O}(\log T)$$ Also if $\kappa$ is the proportion of zeros of $\zeta(s)$ on the critical line $$\kappa:=\liminf_{T\to \infty} \frac{N_0(T)}{N(T)}$$ then we prove as a consequence that $\kappa=1$.
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https://arxiv.org/abs/2205.00811v10
|
Quantum many-body systems present substantial technical challenges from both analytical and numerical perspectives. Despite these difficulties, some progress has been made, including studies of interacting atomic gases and interacting quantum spins. Furthermore, the potential for criticality to enhance engine performance has been demonstrated, suggesting a promising direction for future investigation. Here, we explore the performance of a quantum Otto cycle using a long-range Ising chain as the working substance. We consider an idealized cycle consisting of two adiabatic transformations and two perfect thermalizations, eliminating dissipation. Analyzing both engine and refrigerator modes, we investigate the influence of particle number, varied from $10$ to $100$, on efficiencies and behavior near the critical point of the phase transition, which we characterize using a scaling factor. We also examine how internal factors, specifically, the power-law exponent, the number of particles, and the hot and cold reservoir temperatures, affect the system's operation in different modes. Our results reveal that these factors have a different impact compared to their classical counterparts.
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https://arxiv.org/abs/2502.01469v1
|
100 prisoners and a light bulb is a long standing mathematical puzzle. The problem was studied mostly in 2002 [5], 2003 [1], and 2004 [3]. Solutions in published articles had average number of visits above 3850, but best solutions on forums had (declared) average number of visits around 3500. I spent some time in 2007-2009 to optimize the communication strategy and I pushed the average number of visits below 3390, seems no new ideas appear after it. Recently I have met several people familiar with published papers from 2002-2003 but not knowing newer results. Even after 2009 several papers on the topic were published where the new results were not mentioned [4]. Whole book was written about the problem [2]. This is why I am writing this summary.
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https://arxiv.org/abs/2208.00771v1
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We describe the results of observations with the 100m Robert C. Byrd Green Bank Telescope (GBT) in the HI line of 105 nearby dwarf galaxies, 60 of which were discovered recently in the DESI Legacy Imaging Surveys. Of 105 objects observed, we detected 77 galaxies with the following median parameters: an HI-flux of 0.69 Jy km/s, a heliocentric velocity of 732 km/s, and a $W_{50}$ line width of 32 km/s. 70 are isolated late-type objects and 35 are new probable satellites of nearby spiral galaxies (NGC 628, NGC 2787, NGC 3556, NGC 4490, NGC 4594 and NGC 5055). The detected galaxies are predominantly gas-rich systems with a median gas-to-stellar-mass ratio of 1.87. In general, they follow the classic Tully-Fisher relation obtained for large disk-dominated spiral galaxies if their $M_{21}$ magnitudes are used instead of B-magnitudes.
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https://arxiv.org/abs/2505.19248v1
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