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2004-12-30
The Construction of a Partially Regular Solution to the Landau-Lifshitz-Gilbert Equation in $\mathbb{R}^2$
We establish a framework to construct a global solution in the space of finite energy to a general form of the Landau-Lifshitz-Gilbert equation in $\mathbb{R}^2$. Our characterization yields a partially regular solution, smooth away from a 2-dimensional locally finite Hausdorff measure set. This construction relies on ...
0412534v1
2002-01-13
Inverse Cascade Regime in Shell Models of 2-Dimensional Turbulence
We consider shell models that display an inverse energy cascade similar to 2-dimensional turbulence (together with a direct cascade of an enstrophy-like invariant). Previous attempts to construct such models ended negatively, stating that shell models give rise to a "quasi-equilibrium" situation with equipartition of t...
0201020v1
2002-04-23
Algebraic decay in hierarchical graphs
We study the algebraic decay of the survival probability in open hierarchical graphs. We present a model of a persistent random walk on a hierarchical graph and study the spectral properties of the Frobenius-Perron operator. Using a perturbative scheme, we derive the exponent of the classical algebraic decay in terms o...
0204056v1
2004-03-11
Statistics of active vs. passive advections in magnetohydrodynamic turbulence
Active turbulent advection is considered in the context of magneto-hydrodynamics. In this case, an auxiliary passive field bears no apparent connection to the active field. The scaling properties of the two fields are different. In the framework of a shell model, we show that the two-point structure function of the pas...
0403017v1
2006-01-19
Drift of particles in self-similar systems and its Liouvillian interpretation
We study the dynamics of classical particles in different classes of spatially extended self-similar systems, consisting of (i) a self-similar Lorentz billiard channel, (ii) a self-similar graph, and (iii) a master equation. In all three systems the particles typically drift at constant velocity and spread ballisticall...
0601042v1
1997-11-20
Quantum self-dual codes and symmetric matrices
This paper has been withdrawn since a Gilbert-Varshamov bound for general quantum codes has already appeared in Ekert and Macchiavello, Prys. Rev. Lett. 77, p. 2585, and a Gilbert-Varshamov bound for stabilizer codes connected with orthogonal geometry, or equivalently, with symmetric matrices as in this paper, has been...
9711047v2
2001-06-06
Constraints on Eavesdropping on the BB84 Protocol
An undetected eavesdropping attack must produce count rate statistics that are indistinguishable from those that would arise in the absence of such an attack. In principle this constraint should force a reduction in the amount of information available to the eavesdropper. In this paper we illustrate, by considering a p...
0106034v2
2007-09-14
A complete proof of The Graceful Tree Conjecture using the concept of Edge Degree
We show the Graceful Tree Conjecture holds.
0709.2201v9
2007-09-24
An extension of a result concerning convex geometric graphs
We show a general result known as the Erdos_Sos Conjecture: if $E(G)>{1/2}(k-1)n$ where $G$ has order $n$ then $G$ contains every tree of order $k+1$ as a subgraph.
0709.3590v5
2008-06-13
Heat conduction and Fourier's law by consecutive local mixing and thermalization
We present a first-principles study of heat conduction in a class of models which exhibit a new multi-step local thermalization mechanism which gives rise to Fourier's law. Local thermalization in our models occurs as the result of binary collisions among locally confined gas particles. We explore the conditions under ...
0806.2193v1
2010-04-09
Strict inequalities of critical probabilities on Gilbert's continuum percolation graph
Any infinite graph has site and bond percolation critical probabilities satisfying $p_c^{site}\geq p_c^{bond}$. The strict version of this inequality holds for many, but not all, infinite graphs. In this paper, the class of graphs for which the strict inequality holds is extended to a continuum percolation model. In ...
1004.1596v2
2010-04-15
Rank of mapping tori and companion matrices
Given $f$ in $GL(d,Z)$, it is decidable whether its mapping torus (the semi-direct product of $Z^d$ with $Z$) may be generated by two elements or not; if so, one can classify generating pairs up to Nielsen equivalence. If $f$ has infinite order, the mapping torus of $f^n$ cannot be generated by two elements for $n$ lar...
1004.2649v1
2010-04-30
Limit theory for planar Gilbert tessellations
A Gilbert tessellation arises by letting linear segments (cracks) in the plane unfold in time with constant speed, starting from a homogeneous Poisson point process of germs in randomly chosen directions. Whenever a growing edge hits an already existing one, it stops growing in this direction. The resulting process tes...
1005.0023v1
2010-06-24
Periodic solutions for the Landau-Lifshitz-Gilbert equation
Ferromagnetic materials tend to develop very complex magnetization patterns whose time evolution is modeled by the so-called Landau-Lifshitz-Gilbert equation (LLG). In this paper, we construct time-periodic solutions for LLG in the regime of soft and small ferromagnetic particles which satisfy a certain shape condition...
1006.4765v1
2010-12-19
A counterexample to a Penrose inequality conjectured by Gibbons
We show that the Brill-Lindquist initial data provides a counterexample to a Riemannian Penrose inequality with charge conjectured by G. Gibbons. The observation illustrates a sub-additive characteristic of the area radii for the individual connected components of an outermost horizon as a lower bound of the ADM mass.
1012.4190v2
2012-01-12
Coil-helix transition in poly(L-glutamic acid) : Evidence for a 3-state non-cooperative process
A careful analysis of measurements of circular dichroism of poly(L-glutamic acid) (PGA) shows that the data can be very accurately described by introducing a third state for the PGA configuration, in addition to the helix and coil ones, and considering a simple equilibrium between these three states, without cooperativ...
1201.2566v1
2012-03-20
Vortex dynamics in the presence of excess energy for the Landau-Lifschitz-Gilbert equation
We study the Landau-Lifshitz-Gilbert equation for the dynamics of a magnetic vortex system. We present a PDE-based method for proving vortex dynamics that does not rely on strong well-preparedness of the initial data and allows for instantaneous changes in the strength of the gyrovector force due to bubbling events. Th...
1203.4426v1
2012-12-22
Cumulative Distance Enumerators of Random Codes and their Thresholds
Cumulative weight enumerators of random linear codes are introduced, their asymptotic properties are studied, and very sharp thresholds are exhibited; as a consequence, it is shown that the asymptotic Gilbert-Varshamov bound is a very sharp threshold point for the density of the linear codes whose relative distance is ...
1212.5679v1
2013-01-23
The Importance of Continuous Value Based Project Management in the Context of Requirements Engineering
Despite several scientific achievements in the last years, there are still a lot of IT projects that fail. Researchers found that one out of five IT-projects run out of time, budget or value. Major reasons for this failure are unexpected economic risk factors that emerge during the runtime of projects. In order to be a...
1301.5438v1
2013-04-08
On Automorphisms and Subtowers of an asymptotically optimal Tower of Function Fields
In this article we investigate the automorphism group of an asymptotically optimal tower of function fields introduced by Garcia and Stichtenoth. In particular we provide a detailed description of the decomposition group of some rational places. This group acts on the algebraic-geometric standard codes obtained by the ...
1304.2145v1
2013-05-06
The Moment Generating function for ray lengths in the Half Gilbert Model with Rectangular Cells
In the full rectangular version of Gilbert's tessellation lines extend either horizontally (with east- and west--growing rays) or vertically (north- and south--growing rays) from seed points which form a Poisson point process, each ray stopping when another ray is met. In the half rectangular version, east and south gr...
1305.1289v1
2013-07-15
Degenerate transition pathways for screw dislocations: implications for migration
In body-centred-cubic (bcc) metals migrating 1/2<111> screw dislocations experience a periodic energy landscape with a triangular symmetry. Atomistic simulations, such as those performed using the nudged-elastic-band (NEB) method, generally predict a transition-pathway energy-barrier with a double-hump; contradicting A...
1307.3848v2
2013-08-17
The Riemannian Penrose Inequality with Charge for Multiple Black Holes
We present a proof of the Riemannian Penrose inequality with charge $r\leq m + \sqrt{m^2-q^2}$, where $A=4\pi r^2$ is the area of the outermost apparent horizon with possibly multiple connected components, $m$ is the total ADM mass, and $q$ the total charge of a strongly asymptotically flat initial data set for the Ein...
1308.3771v3
2013-08-23
Quotients and subgroups of Baumslag-Solitar groups
We determine all generalized Baumslag-Solitar groups (finitely generated groups acting on a tree with all stabilizers infinite cyclic) which are quotients of a given Baumslag-Solitar group BS(m,n), and (when BS(m,n) is not Hopfian) which of them also admit BS(m,n) as a quotient. We determine for which values of r,s one...
1308.5122v2
2013-12-17
Limit theory for the Gilbert graph
For a given homogeneous Poisson point process in $\mathbb{R}^d$ two points are connected by an edge if their distance is bounded by a prescribed distance parameter. The behaviour of the resulting random graph, the Gilbert graph or random geometric graph, is investigated as the intensity of the Poisson point process is ...
1312.4861v2
2014-03-13
Fibrations of ordered groupoids and the factorization of ordered functors
We investigate canonical factorizations of ordered functors of ordered groupoids through star-surjective functors. Our main construction is a quotient ordered groupoid, depending on an ordered version of the notion of normal subgroupoid, that results is the factorization of an ordered functor as a star-surjective funct...
1403.3254v2
2014-06-10
A thin-film limit in the Landau-Lifshitz-Gilbert equation relevant for the formation of Néel walls
We consider an asymptotic regime for two-dimensional ferromagnetic films that is consistent with the formation of transition layers (N\'eel walls). We first establish compactness of S2-valued magnetizations in the energetic regime of N\'eel walls and characterize the set of accumulation points. We then prove that N\'ee...
1406.2709v1
2014-12-11
Gamma factors of pairs and a local converse theorem in families
We prove a GL(n)xGL(n-1) local converse theorem for l-adic families of smooth representations of GL(n,F) where F is a finite extension of Q_p and l is different from p. To do so, we also extend the theory of Rankin-Selberg integrals, first introduced by Jacquet, Piatetski-Shapiro, and Shalika, to the setting of familie...
1412.3500v2
2015-05-28
A Geometric Interpretation of the Boolean Gilbert-Johnson-Keerthi Algorithm
The Gilbert-Johnson-Keerthi (GJK) algorithm is an iterative improvement technique for finding the minimum distance between two convex objects. It can easily be extended to work with concave objects and return the pair of closest points. [4] The key operation of GJK is testing whether a Voronoi region of a simplex conta...
1505.07873v1
2016-01-29
Ordered groupoid quotients and congruences on inverse semigroups
We introduce a preorder on an inverse semigroup $S$ associated to any normal inverse subsemigroup $N$, that lies between the natural partial order and Green's ${\mathscr J}$-relation. The corresponding equivalence relation $\simeq_N$ is not necessarily a congruence on $S$, but the quotient set does inherit a natural or...
1601.08194v1
2016-08-16
Closed inverse subsemigroups of graph inverse semigroups
As part of his study of representations of the polycylic monoids, M.V. Lawson described all the closed inverse submonoids of a polycyclic monoid $P_n$ and classified them up to conjugacy. We show that Lawson's description can be extended to closed inverse subsemigroups of graph inverse semigroups. We then apply B. Sche...
1608.04538v1
2016-10-11
Converse theorems and the local Langlands correspondence in families
We prove a descent criterion for certain families of smooth representations of GL_n(F) (F a p-adic field) in terms of the gamma factors of pairs constructed in previous work of the second author. We then use this descent criterion, together with a theory of gamma factors for families of representations of the Weil grou...
1610.03277v1
2016-10-14
An alternative view on dissipation in turbulent flows
An original experimental setup has been elaborated in order to get a better view of turbulent flows in a von Karman geometry. The availability of a very fast camera allowed to follow in time the evolution of the flows. A surprising finding is that the development of smaller whorls ceases earlier than expected and the a...
1610.05356v2
2017-03-02
Small Superposition Dimension and Active Set Construction for Multivariate Integration Under Modest Error Demand
Constructing active sets is a key part of the Multivariate Decomposition Method. An algorithm for constructing optimal or quasi-optimal active sets is proposed in the paper. By numerical experiments, it is shown that the new method can provide sets that are significantly smaller than the sets constructed by the already...
1703.00985v1
2017-03-03
Heat conduction and the nonequilibrium stationary states of stochastic energy exchange processes
I revisit the exactly solvable Kipnis--Marchioro--Presutti model of heat conduction [J. Stat. Phys. 27 65 (1982)] and describe, for one-dimensional systems of arbitrary sizes whose ends are in contact with thermal baths at different temperatures, a systematic characterization of their non-equilibrium stationary states....
1703.01240v1
2017-03-04
Algebraic geometry codes with complementary duals exceed the asymptotic Gilbert-Varshamov bound
It was shown by Massey that linear complementary dual (LCD for short) codes are asymptotically good. In 2004, Sendrier proved that LCD codes meet the asymptotic Gilbert-Varshamov (GV for short) bound. Until now, the GV bound still remains to be the best asymptotical lower bound for LCD codes. In this paper, we show tha...
1703.01441v1
2017-03-17
A finite element approximation for the stochastic Landau--Lifshitz--Gilbert equation with multi-dimensional noise
We propose an unconditionally convergent linear finite element scheme for the stochastic Landau--Lifshitz--Gilbert (LLG) equation with multi-dimensional noise. By using the Doss-Sussmann technique, we first transform the stochastic LLG equation into a partial differential equation that depends on the solution of the au...
1703.05901v1
2017-04-12
The homology of principally directed ordered groupoids
We present some homological properties of a relation $\beta$ on ordered groupoids that generalises the minimum group congruence for inverse semigroups. When $\beta$ is a transitive relation on an ordered groupoid $G$, the quotient $G / \beta$ is again an ordered groupoid, and construct a pair of adjoint functors betwee...
1704.03689v1
2017-06-15
Absence of correlations in the energy exchanges of an exactly solvable model of heat transport with many degrees of freedom
A process based on the exactly solvable Kipnis--Marchioro--Presutti model of heat conduction [J. Stat. Phys. 27 65 (1982)] is described whereby lattice cells share their energies among many identical degrees of freedom while, in each cell, only two of them are associated with energy exchanges connecting neighbouring ce...
1706.04849v1
2017-11-29
On the local converse theorem and the descent theorem in families
We prove an analogue of Jacquet's conjecture on the local converse theorem for \ell-adic families of co-Whittaker representations of GL_n(F), where F is a finite extension of Q_p and \ell does not equal p. We also prove an analogue of Jacquet's conjecture for a descent theorem, which asks for the smallest collection of...
1711.11159v1
2018-06-23
List Decodability of Symbol-Pair Codes
We investigate the list decodability of symbol-pair codes in the present paper. Firstly, we show that list decodability of every symbol-pair code does not exceed the Gilbert-Varshamov bound. On the other hand, we are able to prove that with high probability, a random symbol-pair code can be list decoded up to the Gilbe...
1806.08992v1
2018-07-05
Volumetric performance capture from minimal camera viewpoints
We present a convolutional autoencoder that enables high fidelity volumetric reconstructions of human performance to be captured from multi-view video comprising only a small set of camera views. Our method yields similar end-to-end reconstruction error to that of a probabilistic visual hull computed using significantl...
1807.01950v2
2018-10-26
Immobilization of convex bodies in $R^n$
We extend to arbitrary finite $n$ the notion of immobilization of a convex body $O$ in $R^n$ by a finite set of points $P$ in the boundary of $O$. Because of its importance for this problem, necessary and sufficient conditions are found for the immobilization of an $n$-simplex. A fairly complete geometric description o...
1810.11381v1
2019-01-14
Groupoids and the algebra of rewriting in group presentations
Presentations of groups by rewriting systems (that is, by monoid presentations), have been fruitfully studied by encoding the rewriting system in a $2$--complex -- the Squier complex -- whose fundamental groupoid then describes the derivation of consequences of the rewrite rules. We describe a reduced form of the Squie...
1901.04348v1
2019-05-27
Tuning Free Rank-Sparse Bayesian Matrix and Tensor Completion with Global-Local Priors
Matrix and tensor completion are frameworks for a wide range of problems, including collaborative filtering, missing data, and image reconstruction. Missing entries are estimated by leveraging an assumption that the matrix or tensor is low-rank. Most existing Bayesian techniques encourage rank-sparsity by modelling fac...
1905.11496v1
2019-06-26
Fairness criteria through the lens of directed acyclic graphical models
A substantial portion of the literature on fairness in algorithms proposes, analyzes, and operationalizes simple formulaic criteria for assessing fairness. Two of these criteria, Equalized Odds and Calibration by Group, have gained significant attention for their simplicity and intuitive appeal, but also for their inco...
1906.11333v1
2020-01-14
Neural Architecture Search for Deep Image Prior
We present a neural architecture search (NAS) technique to enhance the performance of unsupervised image de-noising, in-painting and super-resolution under the recently proposed Deep Image Prior (DIP). We show that evolutionary search can automatically optimize the encoder-decoder (E-D) structure and meta-parameters of...
2001.04776v1
2020-07-18
Finslerian convolution metrics and their special classes
Here, it is introduced a concept of convolution metric in Finslerian Geometry. This convolution metric is a kind of function obtained by a given mathematical operation between two Finslerian metrics. Some basic properties of the Finslerian convolution metrics are studied. Then it is characterized Finslerian convolution...
2007.14803v3
2020-09-14
What mathematical billiards teach us about statistical physics?
We survey applications of the theory of hyperbolic (and to a lesser extent non hyperbolic) billiards to some fundamental problems of statistical physics and their mathematically rigorous derivations in the framework of classical Hamiltonian systems.
2009.06284v2
2020-11-29
Applications of the Backus-Gilbert method to linear and some non linear equations
We investigate the use of a functional analytical version of the Backus-Gilbert Method as a reconstruction strategy to get specific information about the solution of linear and slightly non-linear systems with Frech\'et derivable operators. Some a priori error estimates are shown and tested for two classes of problems:...
2011.14407v1
2021-11-30
Global weak solutions for the Landau-Lifshitz-Gilbert-Vlasov-Maxwell system coupled via emergent electromagnetic fields
Motivated by recent models of current driven magnetization dynamics, we examine the coupling of the Landau-Lifshitz-Gilbert equation and classical electron transport governed by the Vlasov-Maxwell system. The interaction is based on space-time gyro-coupling in the form of emergent electromagnetic fields of quantized he...
2111.15482v1
2022-04-02
Introduction to the Artificial Intelligence that can be applied to the Network Automation Journey
The computer network world is changing and the NetDevOps approach has brought the dynamics of applications and systems into the field of communication infrastructure. Businesses are changing and businesses are faced with difficulties related to the diversity of hardware and software that make up those infrastructures. ...
2204.00800v1
2022-05-24
Theory of the Energy Variance in a Quantum Bit
We define a new quantum Hermitian operator (namely, the energy variance operator) which is simply duplicated from the statistical definition of energy variance in classical physics. Its expectation value yields the standard deviation of the energy about the mean value of this latter. We show by use of an exact Hamilton...
2205.12763v1
2022-07-11
Quasilinear rough evolution equations
We investigate the abstract Cauchy problem for a quasilinear parabolic equation in a Banach space of the form \( du_t -L_t(u_t)u_t dt = N_t(u_t)dt + F(u_t)\cdot d\mathbf X_t \), where \( \mathbf X\) is a \( \gamma\)-H\"older rough path for \( \gamma\in(1/3,1/2)\). We explore the mild formulation that combines functiona...
2207.04787v1
2022-08-01
A Pansiot-type subword complexity theorem for automorphisms of free groups
Inspired by Pansiot's work on substitutions, we prove a similar theorem for automorphisms of a free group F of finite rank: if a right-infinite word represents an attracting fixed point of an automorphism of F, the subword complexity of X is equivalent to n, n log log n, n log n, or n^2. The proof uses combinatorial ar...
2208.00676v1
2022-08-13
May the force be with you
Modern methods in dimensionality reduction are dominated by nonlinear attraction-repulsion force-based methods (this includes t-SNE, UMAP, ForceAtlas2, LargeVis, and many more). The purpose of this paper is to demonstrate that all such methods, by design, come with an additional feature that is being automatically comp...
2208.06676v1
2022-10-26
Linearized frequency domain Landau-Lifshitz-Gilbert equation formulation
We present a general finite element linearized Landau-Lifshitz-Gilbert equation (LLGE) solver for magnetic systems under weak time-harmonic excitation field. The linearized LLGE is obtained by assuming a small deviation around the equilibrium state of the magnetic system. Inserting such expansion into LLGE and keeping ...
2210.14525v1
2022-11-10
Secure Aggregation Is Not All You Need: Mitigating Privacy Attacks with Noise Tolerance in Federated Learning
Federated learning is a collaborative method that aims to preserve data privacy while creating AI models. Current approaches to federated learning tend to rely heavily on secure aggregation protocols to preserve data privacy. However, to some degree, such protocols assume that the entity orchestrating the federated lea...
2211.06324v1
2022-12-22
Theory and construction of Quasi-Monte Carlo rules for option pricing and density estimation
In this paper we propose and analyse a method for estimating three quantities related to an Asian option: the fair price, the cumulative distribution function, and the probability density. The method involves preintegration with respect to one well chosen integration variable to obtain a smooth function of the remainin...
2212.11493v2
2022-12-30
Asymptotic stability of 2-domain walls for the Landau-Lifshitz-Gilbert equation in a nanowire with Dzyaloshinskii-Moriya interaction
We consider a ferromagnetic nanowire, with an energy functional $E$ with easy-axis in the direction $e_1$, and which takes into account the Dzyaloshinskii-Moriya interaction. We consider configurations of the magnetization which are perturbations of two well separated domain wall, and study their evolution under the La...
2212.14589v1
2023-01-12
Time Domain Verification of Differential Transmission Line Modeling Methods
The advantages and limitations of time-domain pseudo-random binary sequence (PRBS) excitation methods for system identification of individual modes within a multi-conductor transmission system are discussed. We develop the modifications necessary to standard frequency-domain transmission-line models to match time-domai...
2301.05281v1
2023-01-17
Power Supply Compensation for Capacitive Loads
As ASIC supply voltages approach one volt, the source-impedance goals for power distribution networks are driven ever lower as well. One approach to achieving these goals is to add decoupling capacitors of various values until the desired impedance profile is obtained. An unintended consequence of this approach can be ...
2301.09580v1
2023-01-17
Applications of Optimization Routines in Signal Integrity Analysis
Signal integrity analysis often involves the development of design guidelines through manual manipulation of circuit parameters and judicious interpretation of results. Such an approach can result in significant effort and sub-optimal conclusions. Optimization routines have been well proven to aid analysis across a var...
2301.10157v1
2023-01-17
High Speed Parallel Signal Crosstalk Cancellation Concept
High performance computing (HPC) systems make extensive use of high speed electrical interconnects, in routing signals among processing elements, or between processing elements and memory. Increasing bandwidth demands result in high density, parallel I/O exposed to crosstalk due to tightly coupled transmission lines. T...
2301.10170v1
2023-04-05
Elimination and Factorization
If a matrix $A$ has rank $r$, then its row echelon form (from elimination) contains the identity matrix in its first $r$ independent columns. How do we \emph{interpret the matrix} $F$ that appears in the remaining columns of that echelon form\,? $F$ multiplies those first $r$ independent columns of $A$ to give its $n-r...
2304.02659v1
2023-04-25
Jet: Multilevel Graph Partitioning on Graphics Processing Units
The multilevel heuristic is the dominant strategy for high-quality sequential and parallel graph partitioning. Partition refinement is a key step of multilevel graph partitioning. In this work, we present Jet, a new parallel algorithm for partition refinement specifically designed for Graphics Processing Units (GPUs). ...
2304.13194v2
2023-05-16
QHDL: a Low-Level Circuit Description Language for Quantum Computing
This paper proposes a descriptive language called QHDL, akin to VHDL, to program gate-based quantum computing systems. Unlike other popular quantum programming languages, QHDL targets low-level quantum computing programming and aims to provide a common framework for programming FPGAs and gate-based quantum computing sy...
2305.09419v1
2023-05-21
An Alternative Derivation of the Landau-Lifshitz-Gilbert Equation for Saturated Ferromagnets
The Landau-Lifshitz-Gilbert equation for rigid and saturated ferromagnets is derived using a two-continuum model constructed by H.F. Tiersten for elastic and saturated ferromagnets. The relevant basic laws of physics are applied systematically to the two continua or their combination. The exchange interaction is introd...
2305.18232v1
2023-06-25
Gilbert's conjecture and A new way to octonionic analytic functions from the clifford analysis
In this article we will give a affirmative answer to Gilbert's conjecture on Hardy spaces of Clifford analytic functions in upper half-space of $\mathbb{R}^8$. It depends on a explicit construction of Spinor space $\mathcal{R}_8$ and Clifford algebra $Cl_8$ by octonion algbra. What's more , it gives us an associative w...
2306.14164v1
2023-06-28
Stochastic Landau-Lifshitz-Gilbert equations for frustrated magnets under fluctuating currents
We examine a stochastic Landau-Lifshitz-Gilbert equation for a frustrated ferromagnet with competing first and second order exchange interactions exposed to deterministic and random spin transfer torques in form of transport noise. We prove the existence and pathwise uniqueness of weak martingale solutions in the energ...
2306.15843v1
2023-07-28
MDS, Hermitian Almost MDS, and Gilbert-Varshamov Quantum Codes from Generalized Monomial-Cartesian Codes
We construct new stabilizer quantum error-correcting codes from generalized monomial-Cartesian codes. Our construction uses an explicitly defined twist vector, and we present formulas for the minimum distance and dimension. Generalized monomial-Cartesian codes arise from polynomials in $m$ variables. When $m=1$ our cod...
2307.15488v1
2023-09-06
Optimal Control of the 2D Landau-Lifshitz-Gilbert Equation with Control Energy in Effective Magnetic Field
The optimal control of magnetization dynamics in a ferromagnetic sample at a microscopic scale is studied. The dynamics of this model is governed by the Landau-Lifshitz-Gilbert equation on a two-dimensional bounded domain with the external magnetic field (the control) applied through the effective field. We prove the g...
2309.02786v1
2023-09-22
Relaxed optimal control for the stochastic Landau-Lifshitz-Gilbert equation
We consider the stochastic Landau-Lifshitz-Gilbert equation, perturbed by a real-valued Wiener process. We add an external control to the effective field as an attempt to drive the magnetization to a desired state and also to control thermal fluctuations. We use the theory of Young measures to relax the given control p...
2309.12556v1
2024-01-14
Multilevel Metamodels: A Novel Approach to Enhance Efficiency and Generalizability in Monte Carlo Simulation Studies
Metamodels, or the regression analysis of Monte Carlo simulation (MCS) results, provide a powerful tool to summarize MCS findings. However, an as of yet unexplored approach is the use of multilevel metamodels (MLMM) that better account for the dependent data structure of MCS results that arises from fitting multiple mo...
2401.07294v2
2024-02-29
Evaluating the Gilbert-Varshamov Bound for Constrained Systems
We revisit the well-known Gilbert-Varshamov (GV) bound for constrained systems. In 1991, Kolesnik and Krachkovsky showed that GV bound can be determined via the solution of some optimization problem. Later, Marcus and Roth (1992) modified the optimization problem and improved the GV bound in many instances. In this wor...
2402.18869v1
2003-08-25
Detection of molecular hydrogen at z=1.15 toward HE 0515-4414
A new molecular hydrogen cloud is found in the sub-damped Ly-alpha absorber [log N(HI)=19.88+/-0.05] at the redshift z=1.15 toward the bright quasar HE0515-4414 (zem = 1.71). More than 30 absorption features in the Lyman band system of H2 are identified in the UV spectrum of this quasar obtained with the Space Telescop...
0308432v1
2004-10-04
Dissipative dynamics of topological defects in frustrated Heisenberg spin systems
We study the dynamics of topological defects of a frustrated spin system displaying spiral order. As a starting point we consider the SO(3) nonlinear sigma model to describe long-wavelength fluctuations around the noncollinear spiral state. Besides the usual spin-wave magnetic excitations, the model allows for topologi...
0410082v3
2010-09-14
Modeling laser wakefield accelerators in a Lorentz boosted frame
Modeling of laser-plasma wakefield accelerators in an optimal frame of reference \cite{VayPRL07} is shown to produce orders of magnitude speed-up of calculations from first principles. Obtaining these speedups requires mitigation of a high-frequency instability that otherwise limits effectiveness in addition to solutio...
1009.2727v2
2013-03-07
The coupling between internal waves and shear-induced turbulence in stellar radiation zones: the critical layer
Internal gravity waves (hereafter IGWs) are known as one of the candidates for explaining the angular velocity profile in the Sun and in solar-type main-sequence and evolved stars, due to their role in the transport of angular momentum. Our bringing concerns critical layers, a process poorly explored in stellar physics...
1303.1715v1
2014-05-01
Energy Loss of Solar $p$ Modes due to the excitation of Magnetic Sausage Tube Waves: Importance of Coupling the Upper Atmosphere
We consider damping and absorption of solar $p$ modes due to their energy loss to magnetic tube waves that can freely carry energy out of the acoustic cavity. The coupling of $p$ modes and sausage tube waves is studied in a model atmosphere composed of a polytropic interior above which lies an isothermal upper atmosphe...
1405.0130v2
2015-09-01
Excitation of surface and volume plasmons in metal nanocluster by fast electrons
Surface and volume plasmons excited in a metal cluster by moving electron and corresponding inelastic scattering spectra are studied based on the hydrodynamic approach. Along with the bulk losses traditionally taken into account, the surface and radiative ones are also considered as the physical mechanisms responsible ...
1509.00405v2
2016-01-29
New class of quantum error-correcting codes for a bosonic mode
We construct a new class of quantum error-correcting codes for a bosonic mode which are advantageous for applications in quantum memories, communication, and scalable computation. These 'binomial quantum codes' are formed from a finite superposition of Fock states weighted with binomial coefficients. The binomial codes...
1602.00008v3
2016-05-31
Constraint on a cosmological variation in the proton-to-electron mass ratio from electronic CO absorption
Carbon monoxide (CO) absorption in the sub-damped Lyman-$\alpha$ absorber at redshift $z_{abs} \simeq 2.69$, toward the background quasar SDSS J123714.60+064759.5 (J1237+0647), was investigated for the first time in order to search for a possible variation of the proton-to-electron mass ratio, $\mu$, over a cosmologica...
1605.09742v1
2017-11-01
Entanglement entropy of a three-spin interacting spin chain with a time-reversal breaking impurity at one boundary
We investigate the effect of a time-reversal breaking impurity term on both the equilibrium and non-equilibrium critical properties of entanglement entropy (EE) in a three-spin interacting transverse Ising model which can be mapped to a one-dimensional p-wave superconductor with next-nearest-neighbor hopping. Due to th...
1711.01164v2
2018-01-23
Predicting Quasar Continua Near Lyman-$α$ with Principal Component Analysis
Measuring the proximity effect and the damping wing of intergalactic neutral hydrogen in quasar spectra during the epoch of reionization requires an estimate of the intrinsic continuum at rest-frame wavelengths $\lambda_{\rm rest}\sim1200$-$1260$ {\AA}. In contrast to previous works which used composite spectra with ma...
1801.07679v1
2018-05-23
Quantifying the validity and breakdown of the overdamped approximation in stochastic thermodynamics: Theory and experiment
Stochastic thermodynamics provides an important framework to explore small physical systems where thermal fluctuations are inevitable. In the studies of stochastic thermodynamics, some thermodynamic quantities, such as the trajectory work, associated with the complete Langevin equation (the Kramers equation) are often ...
1805.09080v3
2018-09-05
Experiments on wave propagation in grease ice: combined wave gauges and PIV measurements
Water wave attenuation by grease ice is a key mechanism for the polar regions, as waves in ice influence many phenomena such as ice drift, ice breaking, and ice formation. However, the models presented so far in the literature are limited in a number of regards, and more insights are required from either laboratory exp...
1809.01476v2
2022-02-08
Evolution of energy, momentum, and spin parameter in dark matter flow and integral constants of motion
N-body equations of motion in comoving system and expanding background are reformulated in a transformed system with static background and fixed damping. The energy and momentum evolution in dark matter flow are rigorously formulated for both systems. The energy evolution in transformed system has a simple form that is...
2202.04054v2
2022-09-10
Self-Consistent Computation of Spin Torques and Magneto-Resistance in Tunnel Junctions and Magnetic Read-Heads with Metallic Pinhole Defects
A three-dimensional self-consistent spin transport model is developed, which includes both tunnelling transport, as well as metallic transport. Using the spin accumulation computed either side of a tunnel barrier, spin torques are obtained, and it is shown the model reproduces both damping-like and field-like spin-tran...
2209.04613v1
2023-06-23
Nonlinear asymptotic stability and transition threshold for 2D Taylor-Couette flows in Sobolev spaces
In this paper, we investigate the stability of the 2-dimensional (2D) Taylor-Couette (TC) flow for the incompressible Navier-Stokes equations. The explicit form of velocity for 2D TC flow is given by $u=(Ar+\frac{B}{r})(-\sin \theta, \cos \theta)^T$ with $(r, \theta)\in [1, R]\times \mathbb{S}^1$ being an annulus and $...
2306.13562v1
2023-12-18
Size dependent optical response in coupled systems of plasmons and electron-hole pairs in metallic nanostructures
In bulk materials, the collective modes and individual modes are orthogonal each other, and no connection occurs if there is no damping processes. In the presence of damping, the collective modes, i.e., plasmons decay into the hot carriers. In finite systems, the collective and individual modes are coupled by the Coulo...
2312.10867v2
2024-03-04
Cosmic-ray diffusion in two local filamentary clouds
A fairly uniform cosmic-ray (CR) distribution is observed near the Sun, except in the nearby Eridu cloud, which shows an unexplained 30-50% deficit in GeV to TeV CR flux. To explore the origin of this deficit, we studied the Reticulum cloud, which shares notable traits with Eridu: a comparable distance in the low-densi...
2403.02466v1
1999-04-20
Experimentally Derived Dielectronic Recombination Rate Coefficients for Heliumlike C V and Hydrogenic O VIII
Using published measurements of dielectronic recombination (DR) resonance strengths and energies for C V to C IV and O VIII to O VII, we have calculated the DR rate coefficient for these ions. Our derived rates are in good agreement with multiconfiguration, intermediate-coupling and multiconfiguration, fully-relativist...
9904258v1
2016-10-12
Optical Properties Of Nanometer-Scale Structures
Two approaches (micro- and macro- investigations) are used to determine the dimension dependences of the optical parameters of the nanometer-scale layers of materials. It is shown that both an index of refraction and coefficient of absorption depend strongly on the thickness of the layer. In this region of thicknesses,...
1610.03775v1
1992-06-18
Wormholes and Supersymmetry
Revisions: reference added to: G. Gilbert, {\sl Nucl.Phys.} {\bf B328}, 159 (1989)
9206072v2
1993-05-26
Musings on Magnus
The object of this paper is to describe a simple method for proving that certain groups are residually torsion-free nilpotent, to describe some new parafree groups and to raise some new problems in honour of the memory of Wilhelm Magnus.
9305201v1
2001-10-17
Expected number of distinct part sizes in a random integer composition
The asymptotics, as $n\to\infty$, for the expected number of distinct part sizes in a random composition of an integer n is obtained.
0110189v1
2003-12-29
Non-hopfian relatively free groups
To solve problems of Gilbert Baumslag and Hanna Neumann, posed in the 1960's, we construct a nontrivial variety of groups all of whose noncyclic free groups are non-hopfian.
0312491v1
2005-10-26
Winning rate in the full-information best choice problem
Following a long-standing suggestion by Gilbert and Mosteller, we derive an explicit formula for the asymptotic winning rate in the full-information problem of the best choice.
0510568v3
2007-12-20
The dark matter as a light gravitino (II)
We address the question of gravitino dark matter in the context of gauge mediated supersymmetry breaking models.
0712.3465v1