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arxiv_dataset-1500910.1936 | Fermion mass hierarchy and new physics at the TeV scale
hep-ph
In this talk, I present a new framework to understand the long-standing
fermion mass hierarchy puzzle. We extend the Standard Model gauge symmetry by
an extra local U(1)_S symmetry, broken spontaneously at the electroweak scale.
All the SM particles are singlet with respect to this U(1)_S. We also introduce
additional flavor symmetries, U(1)_F's, with flavon scalars F_i, as well as
vectorlike quarks and leptons at the TeV scale. The flavon scalars have VEV in
the TeV scale. Only the top quark has the usual dimension four Yukawa coupling.
EW symmetry breaking to all other quarks and leptons are propagated through the
messenger field, S through their interactions involving the heavy vector-like
fermions and S, as well as through their interactions involving the vector-like
fermions and F_i. In addition the explaining the hierarchy of the charged
fermion masses and mixings, the model has several interesting predictions for
Higgs decays, flavor changing neutral current processes in the top and the b
quark decays, decays of the new singlet scalars to the new Z' boson, as well as
productions of the new vectorlike quarks. These predictions can be tested at
the LHC.
| arxiv topic:hep-ph |
arxiv_dataset-1501910.2036 | New interpretations for noncrossing partitions of classical types
math.CO
We interpret noncrossing partitions of type $B$ and type $D$ in terms of
noncrossing partitions of type $A$. As an application, we get type-preserving
bijections between noncrossing and nonnesting partitions of type $B$, type $C$
and type $D$ which are different from those in the recent work of Fink and
Giraldo. We also define Catalan tableaux of type $B$ and type $D$, and find
bijections between them and noncrossing partitions of type $B$ and type $D$
respectively.
| arxiv topic:math.CO |
arxiv_dataset-1502910.2136 | Type-I Error or Mass Bias ? An Investigation on the Omega_b Discovery
hep-ex
The D0 and CDF collaborations recently published two independent analyses
that both claim to represent the observation of the Omega_b particle, a baryon
made up by a (bss) quark combination. Both signals are estimated to exceed the
statistical significance of five standard deviations; however, the mass
measurements derived from the candidates differ by over six standard
deviations, accounting for estimated systematics. Measured rates also appear to
differ, although they remain compatible within the large uncertainties.
In this paper the author recomputes the significance of the D0 result,
showing that it was considerably overestimated in the original publication; he
then investigates with a pseudoexperiment-based approach which, among different
hypotheses, appears the most likely cause of the observed discrepancy between
the D0 and CDF signals.
| arxiv topic:hep-ex |
arxiv_dataset-1503910.2236 | Adiabatic perturbation theory: from Landau-Zener problem to quenching
through a quantum critical point
cond-mat.stat-mech
We discuss the application of the adiabatic perturbation theory to analyze
the dynamics in various systems in the limit of slow parametric changes of the
Hamiltonian. We first consider a two-level system and give an elementary
derivation of the asymptotics of the transition probability when the tuning
parameter slowly changes in the finite range. Then we apply this perturbation
theory to many-particle systems with low energy spectrum characterized by
quasiparticle excitations. Within this approach we derive the scaling of
various quantities such as the density of generated defects, entropy and
energy. We discuss the applications of this approach to a specific situation
where the system crosses a quantum critical point. We also show the connection
between adiabatic and sudden quenches near a quantum phase transitions and
discuss the effects of quasiparticle statistics on slow and sudden quenches at
finite temperatures.
| arxiv topic:cond-mat.stat-mech |
arxiv_dataset-1504910.2336 | Suppressed spin dephasing for 2D and bulk electrons in GaAs wires due to
engineered cancellation of spin-orbit interaction terms
cond-mat.mes-hall
We report a study of suppressed spin dephasing for quasi-one-dimensional
electron ensembles in wires etched into a GaAs/AlGaAs heterojunction system.
Time-resolved Kerr-rotation measurements show a suppression that is most
pronounced for wires along the [110] crystal direction. This is the fingerprint
of a suppression that is enhanced due to a strong anisotropy in spin-orbit
fields that can occur when the Rashba and Dresselhaus contributions are
engineered to cancel each other. A surprising observation is that this
mechanisms for suppressing spin dephasing is not only effective for electrons
in the heterojunction quantum well, but also for electrons in a deeper bulk
layer.
| arxiv topic:cond-mat.mes-hall |
arxiv_dataset-1505910.2436 | Mechanics and Dynamics of X-Chromosome Pairing at X Inactivation
q-bio.GN q-bio.SC
At the onset of X Chromosomes Inactivation, the vital process whereby female
mammal cells equalize X products with respect to males, the X chromosomes are
colocalized along their Xic (X-Inactivation Center) regions. The mechanism
inducing recognition and pairing of the X's remains, though, elusive. Starting
from recent discoveries on the molecular factors and on the DNA sequences (the
so-called ``pairing sites'') involved, we dissect the mechanical basis of Xic
colocalization by using a Statistical Physics model. We show that soluble DNA
specific binding molecules, as those experimentally identified, can be indeed
sufficient to induce the spontaneous colocalization of the homologous
chromosomes, but only when their concentration, or chemical affinity, rises
above a threshold value, as a consequence of a thermodynamic phase transition.
We derive the likelihood of pairing and its probability distribution.
Chromosome dynamics has two stages: an initial independent Brownian diffusion
followed, after a characteristic time scale, by recognition and pairing.
Finally, we investigate the effects of DNA deletion/insertions in the region of
pairing sites and compare model predictions to available experimental data.
| arxiv topic:q-bio.GN q-bio.SC |
arxiv_dataset-1506910.2536 | Quasiprojective varieties admitting Zariski dense entire holomorphic
curves
math.CV math.AG
Let $X$ be a complex quasiprojective variety. A result of
Noguchi-Winkelmann-Yamanoi shows that if $X$ admits a Zariski dense entire
curve, then its quasi-Albanese map is a fiber space. We show that the orbifold
structure induced by a properly birationally equivalent map on the base is
special in this case. As a consequence, if $X$ is of log-general type with
$\bar q(X)\geq\dim X$, then any entire curve is contained in a proper
subvariety in $X$.
| arxiv topic:math.CV math.AG |
arxiv_dataset-1507910.2636 | Monte carlo study of the physics performance of a digital hadronic
calorimeter
physics.ins-det hep-ex
A digital hadronic calorimeter using MICROMEGAS as active elements is a very
promising choice for particle physics experiments at future lepton colliders.
These experiments will be optimized for application of the particle flow
algorithm and therefore require calorimeters with very fine lateral
segmentation. A 1 m2 prototype based on MICROMEGAS chambers with 1x1 cm2
readout pads is currently being developed at LAPP. The GEANT4 simulation of the
physics performance of a MICROMEGAS calorimeter is presented. The main
characteristics, such as energy resolution, linearity and shower profile, have
been carefully examined for various passive materials with pions over a wide
energy range from 3 to 200 GeV. The emphasis is put on the comparison of the
analog and digital readout.
| arxiv topic:physics.ins-det hep-ex |
arxiv_dataset-1508910.2736 | The general solution of the linear difference equation of degree-2 and
the continued fraction produced from this equation
math.GM
In this article we give, for the fist time the solution of the general
difference equation of 2-degree. We also give as application the expansion of a
continued fraction into series, which was first proved, found in the past by
the author.
| arxiv topic:math.GM |
arxiv_dataset-1509910.2836 | Ergodic solenoids and generalized currents
math.DG math.DS
We introduce the concept of solenoid as an abstract laminated space. We do a
thorough study of solenoids, leading to the notion of ergodic and uniquely
ergodic solenoids. We define generalized currents associated with immersions of
oriented solenoids with a transversal measure into smooth manifolds,
generalizing Ruelle-Sullivan currents.
| arxiv topic:math.DG math.DS |
arxiv_dataset-1510910.2936 | Quantum geometry and quantum dynamics at the Planck scale
gr-qc
Canonical quantum gravity provides insights into the quantum dynamics as well
as quantum geometry of space-time by its implications for constraints. Loop
quantum gravity in particular requires specific corrections due to its
quantization procedure, which also results in a discrete picture of space. The
corresponding changes compared to the classical behavior can most easily be
analyzed in isotropic models, but perturbations around them are more involved.
For one type of corrections, consistent equations have been found which shed
light on the underlying space-time structure at the Planck scale: not just
quantum dynamics but also the concept of space-time manifolds changes in
quantum gravity. Effective line elements provide indications for possible
relationships to other frameworks, such as non-commutative geometry.
| arxiv topic:gr-qc |
arxiv_dataset-1511910.3036 | Axion luminosity of Active Galactic Nuclei
astro-ph.CO hep-ph
We compute the flux of axions from Active Galactic Nuclei (AGN). Axions can
be produced in the accretion disk by the Compton, Bremsstrahlung and Primakoff
processes. We find that the axion luminosity due to these processes is
negligible in comparison to the photon luminosity from AGNs. We also compute
the luminosity of a hypothetical pseudoscalar, with very small mass, from the
AGN atmosphere due to the phenomenon of pseudoscalar-photon mixing in
background magnetic field. In this case we find that for some parameter ranges,
the pseudoscalar flux can exceed that of photons. We comment on the
implications of this result on the observed large scale alignment of optical
polarizations from AGNs.
| arxiv topic:astro-ph.CO hep-ph |
arxiv_dataset-1512910.3136 | Well-posedness in smooth function spaces for the moving-boundary 1-D
compressible Euler equations in physical vacuum
math.AP
The free-boundary compressible 1-D Euler equations with moving physical
vacuum boundary are a system of hyperbolic conservation laws which are both
characteristic and degenerate. The physical vacuum singularity (or
rate-of-degeneracy) requires the sound speed $c= \gamma \rho^{\gamma -1}$ to
scale as the square-root of the distance to the vacuum boundary, and has
attracted a great deal of attention in recent years. We establish the existence
of unique solutions to this system on a short time-interval, which are smooth
(in Sobolev spaces) all the way to the moving boundary. The proof is founded on
a new higher-order Hardy-type inequality in conjunction with an approximation
of the Euler equations consisting of a particular degenerate parabolic
regularization. Our regular solutions can be viewed as degenerate viscosity
solutions.
| arxiv topic:math.AP |
arxiv_dataset-1513910.3236 | Integrable Systems and Poisson-Lie T-duality: a finite dimensional
example
math-ph math.MP
We study the deep connection between integrable models and Poisson-Lie
T-duality working on a finite dimensional example constructed on SL(2,C) and
its Iwasawa factors SU(2) and B. We shown the way in which Adler-Kostant-Symes
theory and collective dynamics combine to solve the equivalent systems from
solving the factorization problem of an exponential curve in SL(2,C). It is
shown that the Toda system embraces the dynamics of the systems on SU(2) and B.
| arxiv topic:math-ph math.MP |
arxiv_dataset-1514910.3336 | On Prediction of EOP
physics.geo-ph physics.data-an
Two methods of prediction of the Pole coordinates and TAI-UTC were tested --
extrapolation of the deterministic components and ARIMA. It was found that each
of these methods is most effective for certain length of prognosis. For
short-time prediction ARIMA algorithm yields more accurate prognosis, and for
long-time one extrapolation is preferable. So, the combined algorithm is being
used in practice of IAA EOP Service. The accuracy of prognosis is close to
accuracy of IERS algorithms. For prediction of nutation the program KSV-1996-1
by T. Herring is being used.
| arxiv topic:physics.geo-ph physics.data-an |
arxiv_dataset-1515910.3436 | Schrodinger-Poisson system with steep potential well
math.AP math-ph math.MP
We study the following Schr\"odinger-Poisson system (P_\lambda)\{ll}
-\Delta u + (1+\mu g(x))u+\lambda \phi (x) u =|u|^{p-1}u, x\in \mathbb{R}^3,
| arxiv topic:math.AP math-ph math.MP |
arxiv_dataset-1516910.3536 | Apsidal advance in SS 433?
astro-ph.GA
Context. The Galactic microquasar SS 433 launches oppositely directed jets at
speeds approximately a quarter of the speed of light. Both the speed and
direction of the jets exhibit small fluctuations. A component of the speed
variation has 13 day periodicity and the orbital phase at which its maximum
speed occurs has advanced approximately 90 degrees in 25 years. Aims. To
examine the possibility that these variations are associated with a mildly
eccentric orbit and conditions necessary to achieve this apsidal advance.
Methods. The advance of the orbital phase for maximum speed is taken to be
advance of the apses of the putative elliptical orbit. It is compared with
calculations of the effects of tides induced in the companion and also with
gravitational perturbations from the circumbinary disc. These calculations are
made in the light of recent results on the SS 433 system. Results. The 13 day
periodicity in the speed of the jets of SS 433 might be attributed to a mildly
elliptical orbit, through periodic approaches of the donor and the compact
object. Advance of the apses of such an elliptical orbit due to tidal effects
induced in a normal companion looks to be to small; if caused by the
circumbinary disc the mass of the inner regions of that disc is ~ 0.15 solar
masses.
| arxiv topic:astro-ph.GA |
arxiv_dataset-1517910.3636 | Relativistic correction to $e^{+}e^{-}\to J/\psi+gg$ at $B$ factories
and constraint on color-octet matrix elements
hep-ph
We calculate the relativistic correction to $J/\psi$ production in the
color-singlet process $e^{+}e^{-}\to J/\psi+gg$ at B-factories. We employ the
non-relativistic QCD (NRQCD) factorization approach, where the short-distance
coefficients are calculated perturbatively and the long-distance matrix
elements are extracted from the decays of $J/\psi$ into $e^{+}e^{-}$ and light
hadrons. We find that the $O(v^2)$ relativistic correction can enhance the
cross section by a factor of 20-30%, comparable to the enhancement due to the
$O(\alpha_s)$ radiative correction obtained earlier. Combining the relativistic
correction with the QCD radiative correction, we find that the color-singlet
contribution to $e^{+}e^{-}\to J/\psi+gg$ can saturate the latest observed
cross section $\sigma(e^{+}e^{-}\to J/\psi+X_{\mathrm{non-c\bar{c}}})=0.43
\pm0.09\pm0.09$ pb by Belle, thus leaving little room to the color-octet
contributions. This gives a very stringent constraint on the color-octet
contribution, and may imply that the values of color-octet matrix elements are
much smaller than expected earlier by using the naive velocity scaling rules or
extracted from fitting experimental data with the leading-order calculations.
| arxiv topic:hep-ph |
arxiv_dataset-1518910.3736 | A Fault-tolerant Structure for Reliable Multi-core Systems Based on
Hardware-Software Co-design
cs.AR
To cope with the soft errors and make full use of the multi-core system, this
paper gives an efficient fault-tolerant hardware and software co-designed
architecture for multi-core systems. And with a not large number of test
patterns, it will use less than 33% hardware resources compared with the
traditional hardware redundancy (TMR) and it will take less than 50% time
compared with the traditional software redundancy (time redundant).Therefore,
it will be a good choice for the fault-tolerant architecture for the future
high-reliable multi-core systems.
| arxiv topic:cs.AR |
arxiv_dataset-1519910.3836 | Redshift Sensitivity of the Kaiser Effect
astro-ph.CO
We explore potential strategies for testing General Relativity via the
coherent motions of galaxies. Our position at z=0 provides the reference point
for distance measures in cosmology. By contrast, the Cosmic Microwave
Background at z ~ 1100 acts as the point of reference for the growth of large
scale structure. As a result, we find there is a lack of synergy between growth
and distance measures. We show that when measuring the gravitational growth
index gamma using redshift-space distortions, typically 80% of the signal
corresponds to the local growth rate at the galaxy bin location, while the
remaining fraction is determined by its behaviour at higher redshifts.
In order to clarify whether modified gravity may be responsible for the dark
energy phenomenon, the aim is to search for a modification to the growth of
structure. One might expect the magnitude of this deviation to be commensurate
with the apparent dark energy density Omega_Lambda(z). This provides an
incentive to study redshift-space distortions (RSD) at as low a redshift as is
practical. Specifically, we find the region around z = 0.5 offers the optimal
balance of available volume and signal strength.
| arxiv topic:astro-ph.CO |
arxiv_dataset-1520910.3936 | Admissible Strategies in Semimartingale Portfolio Selection
q-fin.CP math.OC math.PR q-fin.PM
The choice of admissible trading strategies in mathematical modelling of
financial markets is a delicate issue, going back to Harrison and Kreps (1979).
In the context of optimal portfolio selection with expected utility preferences
this question has been a focus of considerable attention over the last twenty
years. We propose a novel notion of admissibility that has many pleasant
features - admissibility is characterized purely under the objective measure;
each admissible strategy can be approximated by simple strategies using finite
number of trading dates; the wealth of any admissible strategy is a
supermartingale under all pricing measures; local boundedness of the price
process is not required; neither strict monotonicity, strict concavity nor
differentiability of the utility function are necessary; the definition
encompasses both the classical mean-variance preferences and the monotone
expected utility. For utility functions finite on the whole real line, our
class represents a minimal set containing simple strategies which also contains
the optimizer, under conditions that are milder than the celebrated reasonable
asymptotic elasticity condition on the utility function.
| arxiv topic:q-fin.CP math.OC math.PR q-fin.PM |
arxiv_dataset-1521910.4036 | Symmetries of spin systems and Birman-Wenzl-Murakami algebra
nlin.SI hep-th math.QA
We consider integrable open spin chains related to the quantum affine
algebras U_q(o(3)) and U_q(A_2^{(2)}). We discuss the symmetry algebras of
these chains with the local C^3 space related to the Birman-Wenzl-Murakami
algebra. The symmetry algebra and the Birman-Wenzl-Murakami algebra centralize
each other in the representation space, and this defines the structure of the
spin system spectra. Consequently, the corresponding multiplet structure of the
energy spectra is obtained.
| arxiv topic:nlin.SI hep-th math.QA |
arxiv_dataset-1522910.4136 | Some Algebraic Geometry Aspects of Gravitational Theories with Covariant
and Contravariant Connections and Metrics (GTCCCM) and Possible Applications
to Theories with Extra Dimensions
hep-th
On the base of the distinction between covariant and contravariant metric
tensor components, an approach from algebraic geometry will be proposed, aimed
at finding new solutions of the Einstein's equations both in GTCCCM and in
standard gravity theory, if these equations are treated as algebraic equations.
As a partial case, some physical applications of the approach have been
considered in reference to theories with extra dimensions. The s.c. "length
function" l(x) has been introduced and has been found as a solution of
quasilinear differential equations in partial derivatives for two different
cases, corresponding to "compactification + rescaling" and "rescaling +
compactification" of the type I low-energy string theory action. New (although
complicated) relations between the parameters in the action have been found,
valid also for the standard approach in theories with extra dimensions.
| arxiv topic:hep-th |
arxiv_dataset-1523910.4236 | Neutron star properties in density-dependent relativistic Hartree-Fock
theory
nucl-th
With the equations of state provided by the newly developed density dependent
relativistic Hartree-Fock (DDRHF) theory for hadronic matter, the properties of
the static and $\beta$-equilibrium neutron stars without hyperons are studied
for the first time, and compared to the predictions of the relativistic mean
field (RMF) models and recent observational data. The influences of Fock terms
on properties of asymmetric nuclear matter at high densities are discussed in
details. Because of the significant contributions from the $\sigma$- and
$\omega$-exchange terms to the symmetry energy, large proton fractions in
neutron stars are predicted by the DDRHF calculations, which strongly affect
the cooling process of the star. The critical mass about 1.45 $M_\odot$, close
to the limit 1.5 $M_\odot$ determined by the modern soft X-ray data analysis,
is obtained by DDRHF with the effective interactions PKO2 and PKO3 for the
occurrence of direct Urca process in neutron stars. The maximum masses of
neutron stars given by the DDRHF calculations lie between 2.45 M$_\odot$ and
2.49 M$_\odot$, which are in reasonable agreement with high pulsar mass $2.08
\pm 0.19 M_\odot$ from PSR B1516+02B. It is also found that the mass-radius
relations of neutron stars determined by DDRHF are consistent with the
observational data from thermal radiation measurement in the isolated neutron
star RX J1856, QPOs frequency limits in LMXBs 4U 0614+09 and 4U 1636-536, and
redshift determined in LMXBs EXO 0748-676.
| arxiv topic:nucl-th |
arxiv_dataset-1524910.4336 | Minimal realizations of linear systems: The "shortest basis" approach
cs.IT cs.SY math.IT math.OC
Given a controllable discrete-time linear system C, a shortest basis for C is
a set of linearly independent generators for C with the least possible lengths.
A basis B is a shortest basis if and only if it has the predictable span
property (i.e., has the predictable delay and degree properties, and is
non-catastrophic), or alternatively if and only if it has the subsystem basis
property (for any interval J, the generators in B whose span is in J is a basis
for the subsystem C_J). The dimensions of the minimal state spaces and minimal
transition spaces of C are simply the numbers of generators in a shortest basis
B that are active at any given state or symbol time, respectively. A minimal
linear realization for C in controller canonical form follows directly from a
shortest basis for C, and a minimal linear realization for C in observer
canonical form follows directly from a shortest basis for the orthogonal system
C^\perp. This approach seems conceptually simpler than that of classical
minimal realization theory.
| arxiv topic:cs.IT cs.SY math.IT math.OC |
arxiv_dataset-1525910.4436 | Cohomologie syntomique: liens avec les cohomologies \'etale et rigide
math.AG
Syntomic cohomology here defined yields a link between rigid cohomology and
etale cohomology, viewing the last one as the fixed points under Frobenius of
the former one. Let V be a complete discrete valuation ring, with perfect
residue field k = V/m of characteristic p > 0 and fraction field K of
characteristic 0. Having defined syntomic cohomology with compact supports of
an abelian sheaf G on a k-scheme X, we show that it coincides with etale
cohomology with compact supports when G is a lisse sheaf. If moreover the
convergent F-isocrystal associated to G comes from an overconvergent isocrystal
E, then the rigid cohomology of E expresses as a limit of syntomic
cohomologies: then the etale cohomology with compact supports of G is the fixed
points of Frobenius acting on the rigid cohomology of E.
| arxiv topic:math.AG |
arxiv_dataset-1526910.4536 | Harnack Inequality for Functional SDEs with Bounded Memory
math.PR
We use a coupling method for functional stochastic differential equations
with bounded memory to establish an analogue of Wang's dimension-free Harnack
inequality \cite{MR1481127}. The strong Feller property for the corresponding
segment process is also obtained.
| arxiv topic:math.PR |
arxiv_dataset-1527910.4636 | On approximation of smoothing probabilities for hidden Markov models
stat.ML math.ST stat.TH
We consider the smoothing probabilities of hidden Markov model (HMM). We show
that under fairly general conditions for HMM, the exponential forgetting still
holds, and the smoothing probabilities can be well approximated with the ones
of double sided HMM. This makes it possible to use ergodic theorems. As an
applications we consider the pointwise maximum a posteriori segmentation, and
show that the corresponding risks converge.
| arxiv topic:stat.ML math.ST stat.TH |
arxiv_dataset-1528910.4736 | Some remarks on the observational constraints on the self-interacting
scalar field model for dark energy
astro-ph.CO gr-qc hep-th
The dark energy component of the cosmic budget is represented by a
self-interacting scalar field. The violation of the null energy condition is
allowed. Hence, such component can also represent a phantom fluid. The model is
tested using supernova type Ia and matter power spectrum data. The supernova
test leads to preferred values for configurations representing the phantom
fluid. The matter power spectrum constraints for the dark energy equation of
state parameter are highly degenerated. In both cases, values for the equation
of state parameter corresponding to the phantom fluid are highly admitted if no
particular prior is used.
| arxiv topic:astro-ph.CO gr-qc hep-th |
arxiv_dataset-1529910.4836 | Performance limitations for sparse matrix-vector multiplications on
current multicore environments
cs.PF
The increasing importance of multicore processors calls for a reevaluation of
established numerical algorithms in view of their ability to profit from this
new hardware concept. In order to optimize the existent algorithms, a detailed
knowledge of the different performance-limiting factors is mandatory. In this
contribution we investigate sparse matrix-vector multiplication, which is the
dominant operation in many sparse eigenvalue solvers. Two conceptually
different storage schemes and computational kernels have been conceived in the
past to target cache-based and vector architectures, respectively. Starting
from a series of microbenchmarks we apply the gained insight on optimized
sparse MVM implementations, whose serial and OpenMP-parallel performance we
review on state-of-the-art multicore systems.
| arxiv topic:cs.PF |
arxiv_dataset-1530910.4936 | Annihilation cross sections and interaction couplings of the dark matter
candidates in the warped and flat extra dimensions
hep-ph
We consider a scenario with an additional scalar standard model singlet
$\phi_S$, living in a single extra dimension of the RS1 background. The zero
mode of this scalar which is localized in the extra dimension is a dark matter
candidate and the annihilation cross section is strongly sensitive to its
localization parameter. As a second scenario, we assume that the standard model
Higgs field is accessible to the fifth flat extra dimension. At first we take
the additional standard model singlet scalar field as accessible to the sixth
extra dimension and its zero mode is a possible dark matter candidate. Second,
we consider that the new standard model singlet, the dark matter candidate,
lives in four dimensions. In both choices the KK modes of the standard model
Higgs field play an observable role for the large values of the
compactification radius $R$ and the effective coupling \lambda_{S} is of the
order of 10^{-2}-10^{-1} (10^{-6}) far from (near to) the resonant
annihilation.
| arxiv topic:hep-ph |
arxiv_dataset-1531910.5036 | Calculation of nucleon strange quark content with dynamical overlap
quarks
hep-lat
We calculate the nucleon strange quark content directly from disconnected
three-point functions. Numerical simulations are carried out in two-flavor QCD
using the overlap quark action with up and down quark masses down to a fifth of
the physical strange quark mass. To improve the statistical accuracy, we
calculate the nucleon two-point functions with the low-mode averaging
technique, whereas the all-to-all quark propagator is used for the disconnected
quark loop. We obtain the y parameter, which is the ratio of the strange and
light quark contents, y = 0.024(45) at the physical point. This is in a good
agreement with our earlier calculation from the nucleon spectrum through the
Feynman-Hellmann theorem.
| arxiv topic:hep-lat |
arxiv_dataset-1532910.5136 | Thermal Motions of the E. Coli Glucose-Galactose Binding Protein Studied
Using Well-Sampled Semi-Atomistic Simulations
physics.bio-ph physics.comp-ph
The E. coli glucose-galactose chemosensory receptor is a 309 residue, 32 kDa
protein consisting of two distinct structural domains. In this computational
study, we studied the protein's thermal fluctuations, including both the large
scale interdomain movements that contribute to the receptor's mechanism of
action, as well as smaller scale motions, using two different computational
methods. We employ extremely fast, "semi-atomistic" Library-Based Monte Carlo
(LBMC) simulations, which include all backbone atoms but "implicit" side
chains. Our results were compared with previous experiments and an all-atom
Langevin dynamics simulation. Both LBMC and Langevin dynamics simulations were
performed using both the apo and glucose-bound form of the protein, with LBMC
exhibiting significantly larger fluctuations. The LBMC simulations are also in
general agreement with the disulfide trapping experiments of Careaga & Falke
(JMB, 1992; Biophys. J., 1992), which indicate that distant residues in the
crystal structure (i.e. beta carbons separated by 10 to 20 angstroms) form
spontaneous transient contacts in solution. Our simulations illustrate several
possible "mechanisms" (configurational pathways) for these fluctuations. We
also observe several discrepancies between our calculations and experiment.
Nevertheless, we believe that our semi-atomistic approach could be used to
study the fluctuations in other proteins, perhaps for ensemble docking, or
other analyses of protein flexibility in virtual screening studies.
| arxiv topic:physics.bio-ph physics.comp-ph |
arxiv_dataset-1533910.5236 | Signature of the interaction between dark energy and dark matter in
observations
gr-qc astro-ph.CO hep-ph hep-th
We investigate the effect of an interaction between dark energy and dark
matter upon the dynamics of galaxy clusters. This effect is computed through
the Layser-Irvine equation, which describes how an astrophysical system reaches
virial equilibrium and was modified to include the dark interactions. Using
observational data from almost 100 purportedly relaxed galaxy clusters we put
constraints on the strength of the couplings in the dark sector. We compare our
results with those from other observations and find that a positive (in the
sense of energy flow from dark energy to dark matter) non vanishing interaction
is consistent with the data within several standard deviations.
| arxiv topic:gr-qc astro-ph.CO hep-ph hep-th |
arxiv_dataset-1534910.5336 | HINODE Observations of Coherent Lateral Motion of Penumbral Filaments
during a X-class Flare
astro-ph.SR
The X-3.4 class flare of 13 December 2006 was observed with a high cadence of
2 minutes at 0.2 arc-sec resolution by HINODE/SOT FG instrument. The flare
ribbons could be seen in G-band images also. A careful analysis of these
observations after proper registration of images show flare related changes in
penumbral filaments of the associated sunspot, for the first time. The
observations of sunspot deformation, decay of penumbral area and changes in
magnetic flux during large flares have been reported earlier in the literature.
In this Letter, we report lateral motion of the penumbral filaments in a
sheared region of the delta-sunspot during the X-class flare. Such shifts have
not been seen earlier. The lateral motion occurs in two phases, (i) motion
before the flare ribbons move across the penumbral filaments and (ii) motion
afterwards. The former motion is directed away from expanding flare ribbons and
lasts for about four minutes. The latter motion is directed in the opposite
direction and lasts for more than forty minutes. Further, we locate a patch in
adjacent opposite polarity spot moving in opposite direction to the penumbral
filaments. Together these patches represent conjugate foot-points on either
side of the polarity inversion line (PIL), moving towards each other. This
converging motion could be interpreted as shrinkage of field lines.
| arxiv topic:astro-ph.SR |
arxiv_dataset-1535910.5436 | Measuring the Transmission Matrix in Optics : An Approach to the Study
and Control of Light Propagation in Disordered Media
physics.optics
We introduce a method to experimentally measure the monochromatic
transmission matrix of a complex medium in optics. This method is based on a
spatial phase modulator together with a full-field interferometric measurement
on a camera. We determine the transmission matrix of a thick random scattering
sample. We show that this matrix exhibits statistical properties in good
agreement with random matrix theory and allows light focusing and imaging
through the random medium. This method might give important insights into the
mesoscopic properties of complex medium.
| arxiv topic:physics.optics |
arxiv_dataset-1536910.5536 | Holographic Anyons in the ABJM Theory
hep-th cond-mat.str-el
We consider the holographic anyons in the ABJM theory from three different
aspects of AdS/CFT correspondence. First, we identify the holographic anyons by
using the field equations of supergravity, including the Chern-Simons terms of
the probe branes. We find that the composite of Dp-branes wrapped over CP3 with
the worldvolume magnetic fields can be the anyons. Next, we discuss the
possible candidates of the dual anyonic operators on the CFT side, and find the
agreement of their anyonic phases with the supergravity analysis. Finally, we
try to construct the brane profile for the holographic anyons by solving the
equations of motion and Killing spinor equations for the embedding profile of
the wrapped branes. As a by product, we find a BPS spiky brane for the dual
baryons in the ABJM theory.
| arxiv topic:hep-th cond-mat.str-el |
arxiv_dataset-1537910.5636 | Stochastically Incomplete Manifolds and Graphs
math-ph math.MP
We survey geometric properties which imply the stochastic incompleteness of
the minimal diffusion process associated to the Laplacian on manifolds and
graphs. In particular, we completely characterize stochastic incompleteness for
spherically symmetric graphs and show that, in contrast to the case of
Riemannian manifolds, there exist examples of stochastically incomplete graphs
of polynomial volume growth.
| arxiv topic:math-ph math.MP |
arxiv_dataset-1538910.5736 | The fermion bag approach to lattice field theories
hep-lat
We propose a new approach to the fermion sign problem in systems where there
is a coupling $U$ such that when it is infinite the fermions are paired into
bosons and there is no fermion permutation sign to worry about. We argue that
as $U$ becomes finite fermions are liberated but are naturally confined to
regions which we refer to as {\em fermion bags}. The fermion sign problem is
then confined to these bags and may be solved using the determinantal trick. In
the parameter regime where the fermion bags are small and their typical size
does not grow with the system size, construction of Monte Carlo methods that
are far more efficient than conventional algorithms should be possible. In the
region where the fermion bags grow with system size, the fermion bag approach
continues to provide an alternative approach to the problem but may lose its
main advantage in terms of efficiency. The fermion bag approach also provides
new insights and solutions to sign problems. A natural solution to the "silver
blaze problem" also emerges. Using the three dimensional massless lattice
Thirring model as an example we introduce the fermion bag approach and
demonstrate some of these features. We compute the critical exponents at the
quantum phase transition and find $\nu=0.87(2)$ and $\eta=0.62(2)$.
| arxiv topic:hep-lat |
arxiv_dataset-1539910.5836 | Can the Arrow of Time be understood from Quantum Cosmology?
gr-qc
I address the question whether the origin of the observed arrow of time can
be derived from quantum cosmology. After a general discussion of entropy in
cosmology and some numerical estimates, I give a brief introduction into
quantum geometrodynamics and argue that this may provide a sufficient framework
for studying this question. I then show that a natural boundary condition of
low initial entropy can be imposed on the universal wave function. The arrow of
time is then correlated with the size of the Universe and emerges from an
increasing amount of decoherence due to entanglement with unobserved degrees of
freedom. Remarks are also made concerning the arrow of time in multiverse
pictures and scenarios motivated by dark energy.
| arxiv topic:gr-qc |
arxiv_dataset-1540910.5936 | Convexity properties of the condition number II
math.DG math.NA
In our previous paper [SIMAX 31 n.3 1491-1506(2010)], we studied the
condition metric in the space of maximal rank matrices. Here, we show that this
condition metric induces a Lipschitz-Riemann structure on that space. After
investigating geodesics in such a nonsmooth structure, we show that the inverse
of the smallest singular value of a matrix is a log-convex function along
geodesics (Theorem 1).
We also show that a similar result holds for the solution variety of linear
systems (Theorem 31).
Some of our intermediate results, such as Theorem 12, on the second covariant
derivative or Hessian of a function with symmetries on a manifold, and Theorem
29 on piecewise self-convex functions, are of independent interest.
Those results were motivated by our investigations on the com- plexity of
path-following algorithms for solving polynomial systems.
| arxiv topic:math.DG math.NA |
arxiv_dataset-1541911.0079 | Heterogeneity of Some Cooperation/Competition Properties
physics.soc-ph
We show that the heterogeneity index, which was proposed by Hu and Wang
(Physica A 2008 387 3769), can be used to describe the disparity of the
cooperation sharing or competition gain distributions that is very important
for the cooperation/competition system dynamic understanding. An analytical
relation between the distribution parameters and the heterogeneity index is
derived, which is in a good agreement with the empirical results. Our
theoretical and empirical analyses also show that the relation between the
distribution parameters can be analytically derived from so-called Zhang-Chang
model (Physica A 2006 360 599 and 2007 383 687). This strongly recommends a
possibility to create a general dynamic cooperation/competition model based on
Zhang-Chang model.
| arxiv topic:physics.soc-ph |
arxiv_dataset-1542911.0179 | A Thermodynamic Formalism for density matrices in Quantum Information
math.DS math-ph math.MP quant-ph
We consider new concepts of entropy and pressure for stationary systems
acting on density matrices which generalize the usual ones in Ergodic Theory.
Part of our work is to justify why the definitions and results we describe here
are natural generalizations of the classical concepts of Thermodynamic
Formalism (in the sense of R. Bowen, Y. Sinai and D. Ruelle). It is well-known
that the concept of density operator should replace the concept of measure for
the cases in which we consider a quantum formalism. We consider the operator
$\Lambda$ acting on the space of density matrices $\mathcal{M}_N$ over a finite
$N$-dimensional complex Hilbert space $$ \Lambda(\rho):=\sum_{i=1}^k tr(W_i\rho
W_i^*)\frac{V_i\rho V_i^*}{tr(V_i\rho V_i^*)}, $$ where $W_i$ and $V_i$,
$i=1,2,..., k$ are linear operators in this Hilbert space. In some sense this
operator is a version of an Iterated Function System (IFS). Namely, the
$V_i\,(.)\,V_i^*=:F_i(.)$, $i=1,2,...,k$, play the role of the inverse branches
(i.e., the dynamics on the configuration space of density matrices) and the
$W_i$ play the role of the weights one can consider on the IFS. In this way a
family $W:=\{W_i\}_{i=1,..., k}$ determines a Quantum Iterated Function System
(QIFS). We also present some estimates related to the Holevo bound.
| arxiv topic:math.DS math-ph math.MP quant-ph |
arxiv_dataset-1543911.0279 | Some Identities Involving Three Kinds of Counting Numbers
math.CO
In this note, we present several identities involving binomial coefficients
and the two kind of Stirling numbers.
| arxiv topic:math.CO |
arxiv_dataset-1544911.0379 | On the Conjugacy Classes in the orthogonal and symplectic groups over
algebraically closed fields
math.GR math.AC
Let $\F$ be an algebraically closed field. Let $\V$ be a vector space
equipped with a non-degenerate symmetric or symplectic bilinear form $B$ over
$\F$. Suppose the characteristic of $\F$ is \emph{large}, i.e. either zero or
greater than the dimension of $\V$. Let $I(\V, B)$ denote the group of
isometries. Using the Jacobson-Morozov lemma we give a new and simple proof of
the fact that two elements in $I(\V,B)$ are conjugate if and only if they have
the same elementary divisors.
| arxiv topic:math.GR math.AC |
arxiv_dataset-1545911.0479 | Dynamical Heterogeneity in Lattice Glass Models
cond-mat.stat-mech
In this paper we consider in detail the properties of dynamical heterogeneity
in lattice glass models (LGMs). LGMs are lattice models whose dynamical rules
are based on thermodynamic, as opposed to purely kinetic, considerations. We
devise a LGM that is not prone to crystallization and displays properties of a
fragile glass-forming liquid. Particle motion in this model tends to be locally
anisotropic on intermediate time scales even though the rules governing the
model are isotropic. The model demonstrates violations of the Stokes-Einstein
relation and the growth of various length scales associated with dynamical
heterogeneity. We discuss future avenues of research comparing the predictions
of lattice glass models and kinetically constrained models to atomistic
systems.
| arxiv topic:cond-mat.stat-mech |
arxiv_dataset-1546911.0579 | Remarks on the Configuration Space Approach to Spin-Statistics
quant-ph physics.chem-ph
The angular momentum operators for a system of two spin-zero
indistinguishable particles are constructed, using Isham's Canonical Group
Quantization method. This mathematically rigorous method provides a hint at the
correct definition of (total) angular momentum operators, for arbitrary spin,
in a system of indistinguishable particles. The connection with other
configuration space approaches to spin-statistics is discussed, as well as the
relevance of the obtained results in view of a possible alternative proof of
the spin-statistics theorem.
| arxiv topic:quant-ph physics.chem-ph |
arxiv_dataset-1547911.0679 | Gravity Dual of Spatially Modulated Phase
hep-th cond-mat.str-el gr-qc
We show that the five-dimensional Maxwell theory with the Chern-Simons term
is tachyonic in the presence of a constant electric field. When coupled to
gravity, a sufficiently large Chern-Simons coupling causes instability of the
Reissner-Nordstrom black holes in anti-de Sitter space. The instability happens
only at non-vanishing momenta, suggesting a spatially modulated phase in the
holographically dual quantum field theory in 3+1 dimensions, with spontaneous
current generation in a helical configuration. The three-charge extremal black
hole in the type IIB superstring theory on AdS_5 x S^5 barely satisfies the
stability condition.
| arxiv topic:hep-th cond-mat.str-el gr-qc |
arxiv_dataset-1548911.0779 | The physics and modes of star cluster formation: observations
astro-ph.GA astro-ph.SR
Stellar clusters are born in cold and dusty molecular clouds and the youngest
clusters are embedded to various degrees in dusty dark molecular material. Such
embedded clusters can be considered protocluster systems. The most deeply
buried examples are so heavily obscured by dust that they are only visible at
infrared wavelengths. These embedded protoclusters constitute the nearest
laboratories for direct astronomical investigation of the physical processes of
cluster formation and early evolution. I review the present state of empirical
knowledge concerning embedded cluster systems and discuss the implications for
understanding their formation and subsequent evolution to produce bound stellar
clusters.
| arxiv topic:astro-ph.GA astro-ph.SR |
arxiv_dataset-1549911.0879 | When is there a multipartite maximum entangled state?
quant-ph
For a multipartite quantum system of the dimension $d_1\otimes d_2\otimes...
d_n$, $d_1\ge d_2\ge...\ge d_n$, is there an entangled state {\em maximum} in
the sense that all other states in the system can be obtained from the state
through local quantum operations and classical communications (LOCC)? When
$d_1\ge\Pi_{i=2}^n d_i$, such state exists. We show that this condition is also
necessary. Our proof, somewhat surprisingly, uses results from algebraic
complexity theory.
| arxiv topic:quant-ph |
arxiv_dataset-1550911.0979 | Free products in R. Thompson's group V
math.GR math.DS
We investigate free product structures in R. Thompson's group V, primarily by
studying the topological dynamics associated with V's action on the Cantor Set.
We show that the class of free products which can be embedded into V includes
the free product of any two finite groups, the free product of any finite group
with Q/Z, and the countable non-abelian free groups. We also show the somewhat
surprising result that Z^2*Z does not embed in V, even though V has many
embedded copies of Z^2 and has many embedded copies of free products of pairs
of its subgroups.
| arxiv topic:math.GR math.DS |
arxiv_dataset-1551911.1079 | The canonical 8-form on manifolds with holonomy group Spin(9)
math.DG math-ph math.MP
An explicit expression of the canonical 8-form on a Riemannian manifold with
a Spin(9)-structure, in terms of the nine local symmetric involutions involved,
is given. The list of explicit expressions of all the canonical forms related
to Berger's list of holonomy groups is thus completed. Moreover, some results
on Spin(9)-structures as G-structures defined by a tensor and on the curvature
tensor of the Cayley planes, are obtained.
| arxiv topic:math.DG math-ph math.MP |
arxiv_dataset-1552911.1179 | The $\Lambda(1405)$ as a Hybrid
hep-ph nucl-th
Using the QCD Sum Rule Method, we estimate the mass of the lowest strange
hybrid baryon with $IJ^P=0(1/2)^-$. We find the mass is approximately that of
the $\Lambda(1405)$, whose nature has been a puzzle for many decades. Possible
tests of this result are discussed.
| arxiv topic:hep-ph nucl-th |
arxiv_dataset-1553911.1279 | Morphologies of local Lyman break galaxy analogs II: A Comparison with
galaxies at z=2-4 in ACS and WFC3 images of the Hubble Ultra Deep Field
astro-ph.CO
Lyman break galaxies (LBGs) display a range in structures (from
single/compact to clumpy/extended) that is different from typical local
star-forming galaxies. Recently, we have introduced a sample of rare, nearby
(z<0.3) starbursts that appear to be good analogs of LBGs. These "Lyman Break
Analogs" (LBAs) provide an excellent training set for understanding starbursts
at different redshifts. We present an application of this by comparing the
rest-frame UV/optical morphologies of 30 LBAs with those of sBzK galaxies at
z~2, and LBGs at z~3-4 in the HUDF. The UV/optical colors and sizes of LBAs and
LBGs are very similar, while the BzK galaxies are somewhat redder and larger.
There is significant overlap between the morphologies (G, C, A and M_20) of the
local and high-z samples, although the latter are somewhat less concentrated
and clumpier. We find that in the majority of LBAs the starbursts appear to be
triggered by interactions/mergers. When the images of the LBAs are degraded to
the same sensitivity and resolution as the images of LBGs and BzK galaxies,
these relatively faint asymmetric features are no longer detectable. This
effect is particularly severe in the rest-frame UV. It has been suggested that
high-z galaxies experience intense bursts unlike anything seen locally,
possibly due to cold flows and instabilities. In part, this is based on the
fact that the majority (~70%) of LBGs do not show morphological signatures of
mergers. Our results suggest that this evidence is insufficient, since a large
fraction of such signatures would likely have been missed in current
observations of z>2 galaxies. This leaves open the possibility that clumpy
accretion and mergers remain important in driving the evolution of these
starbursts, together with rapid gas accretion through other means.
| arxiv topic:astro-ph.CO |
arxiv_dataset-1554911.1379 | On Improving the Representation of a Region Achieved by a Sensor Network
cs.NI
This report considers the class of applications of sensor networks in which
each sensor node makes measurements, such as temperature or humidity, at the
precise location of the node. Such spot-sensing applications approximate the
physical condition of the entire region of interest by the measurements made at
only the points where the sensor nodes are located. Given a certain density of
nodes in a region, a more spatially uniform distribution of the nodes leads to
a better approximation of the physical condition of the region. This report
considers the error in this approximation and seeks to improve the quality of
representation of the physical condition of the points in the region in the
data collected by the sensor network. We develop two essential metrics which
together allow a rigorous quantitative assessment of the quality of
representation achieved: the average representation error and the unevenness of
representation error, the latter based on a well-accepted measure of inequality
used in economics. We present the rationale behind the use of these metrics and
derive relevant theoretical bounds on them in the common scenario of a planar
region of arbitrary shape covered by a sensor network deployment. A simple new
heuristic algorithm is presented for each node to determine if and when it
should sense or sleep to conserve energy while also preserving the quality of
representation. Simulation results show that it achieves a significant
improvement in the quality of representation compared to other related
distributed algorithms. Interestingly, our results also show that improved
spatial uniformity has the welcome side-effect of a significant increase in the
network lifetime.
| arxiv topic:cs.NI |
arxiv_dataset-1555911.1479 | Is the spacetime metric Euclidean rather than Lorentzian?
gr-qc hep-th math-ph math.MP quant-ph
My answer to the question in the title is "No". In support of this point of
view, we analyze some examples of saddle-point methods, especially as applied
to quantum "tunneling" in nonrelativistic particle mechanics and in cosmology.
Along the way we explore some of the interrelationships among different ways of
thinking about path-integrals and saddle-point approximations to them.
| arxiv topic:gr-qc hep-th math-ph math.MP quant-ph |
arxiv_dataset-1556911.1579 | GRB Jet Beaming Angle Statistics
astro-ph.HE
Existing theory and models suggest that a Type I (merger) GRB should have a
larger jet beaming angle than a Type II (collapsar) GRB, but so far no
statistical evidence is available to support this suggestion. In this paper, we
obtain a sample of 37 beaming angles and calculate the probability that this is
true. A correction is also devised to account for the scarcity of Type I GRBs
in our sample. The probability is calculated to be 83% without the correction
and 71% with it.
| arxiv topic:astro-ph.HE |
arxiv_dataset-1557911.1679 | XOR gate response in a mesoscopic ring with embedded quantum dots
cond-mat.mes-hall cond-mat.mtrl-sci
We address XOR gate response in a mesoscopic ring threaded by a magnetic flux
$\phi$. The ring, composed of identical quantum dots, is symmetrically attached
to two semi-infinite one-dimensional metallic electrodes and two gate voltages,
viz, $V_a$ and $V_b$, are applied, respectively, in each arm of the ring which
are treated as the two inputs of the XOR gate. The calculations are based on
the tight-binding model and the Green's function method, which numerically
compute the conductance-energy and current-voltage characteristics as functions
of the ring-electrodes coupling strengths, magnetic flux and gate voltages.
Quite interestingly it is observed that, for $\phi=\phi_0/2$ ($\phi_0=ch/e$,
the elementary flux-quantum) a high output current (1) (in the logical sense)
appears if one, and only one, of the inputs to the gate is high (1), while if
both inputs are low (0) or both are high (1), a low output current (0) appears.
It clearly demonstrates the XOR behavior and this aspect may be utilized in
designing the electronic logic gate.
| arxiv topic:cond-mat.mes-hall cond-mat.mtrl-sci |
arxiv_dataset-1558911.1779 | Observation of radiative B^0 -> \phi K^0 \gamma decays
hep-ex
We report the first observation of radiative decay B^0 -> \phi K^0 \gamma
using a data sample of 772x10^6 BBar pairs collected at the Y(4S) resonance
with the Belle detector at the KEKB asymmetric-energy e+e- collider. We observe
a signal of 35+/-8 events with a significance of 5.4 standard deviations
including systematic uncertainties. The measured branching fraction is ${\cal
B}(B^0 -> \phi K^0 \gamma) = (2.66\pm 0.60 \pm 0.32) \times 10^{-6}$. We also
precisely measure ${\cal B}(B^+ -> \phi K^+ \gamma) = (2.34\pm 0.29 \pm 0.23)
\times 10^{-6}$. The uncertainties are statistical and systematic,
respectively. The observed M_{\phi K} mass spectrum differs significantly from
that expected in a three-body phase-space decay.
| arxiv topic:hep-ex |
arxiv_dataset-1559911.1879 | Infinitesimal Hecke Algebras II
math.RT
For W a finite (2-)reflection group and B its (generalized) braid group, we
determine the Zariski closure of the image of B inside the corresponding
Iwahori-Hecke algebra. The Lie algebra of this closure is reductive and
generated in the group algebra of W by the reflections of W. We determine its
decomposition in simple factors. In case W is a Coxeter group, we prove that
the representations involved are unitarizable when the parameters of the
representations have modulus 1 and are close to 1. We consequently determine
the topological closure in this case.
| arxiv topic:math.RT |
arxiv_dataset-1560911.1979 | Transformations of triangle ladder diagrams
hep-th
It is shown how dual space diagrammatic representation of momentum integrals
corresponding to triangle ladder diagrams with an arbitrary number of rungs can
be transformed to half-diamonds. In paper arXiv:0803.3420 [hep-th] the
half-diamonds were related by conformal integral substitution to the diamonds
which represent the dual space image of four-point ladder integrals in the
four-dimensional momentum space. Acting in the way described in the present
paper we do not need to use the known result for diamond (four-point) diagrams
as an external input in deriving relations of arXiv:0803.3420 [hep-th],
however, that result for the diamond diagram arises in the present proof as an
intermediate consequence in a step-by-step diagrammatic transformation from the
triangle ladder diagram to the half-diamond diagrams.
| arxiv topic:hep-th |
arxiv_dataset-1561911.2079 | The data mining II: An analysis of 33 eclipsing binary light-curves
observed by the INTEGRAL/OMC
astro-ph.SR
Thirty-three eclipsing binaries were selected for an analysis from a huge
database of observations made by the INTEGRAL/OMC camera. The photometric data
were processed and analyzed, resulting in a first light-curve study of these
neglected eclipsing binaries. The system CY Lac was discovered to be an
eccentric one. In several systems from this sample even their orbital periods
have been confirmed or modified. Due to missing spectroscopic study of these
stars, further detailed analyses are still needed.
| arxiv topic:astro-ph.SR |
arxiv_dataset-1562911.2179 | Quasi-Hamiltonian groupoids and multiplicative Manin pairs
math.DG math-ph math.MP
We reformulate notions from the theory of quasi-Poisson g-manifolds in terms
of graded Poisson geometry and graded Poisson-Lie groups and prove that
quasi-Poisson g-manifolds integrate to quasi-Hamiltonian g-groupoids. We then
interpret this result within the theory of Dirac morphisms and multiplicative
Manin pairs, to connect our work with more traditional approaches, and also to
put it into a wider context suggesting possible generalizations.
| arxiv topic:math.DG math-ph math.MP |
arxiv_dataset-1563911.2279 | How can CP violation in the neutrino sector be large in a
$2\leftrightarrow 3$ symmetric model?
hep-ph
Based on a neutrino mass matrix model in which a 2-3 symmetry is only broken
by a phase parameter, it is investigated how the lepton mixing matrix can
deviate from the so-called tribimaximal mixing under a condition that CP is
maximally violated.
| arxiv topic:hep-ph |
arxiv_dataset-1564911.2379 | Supersolid phase of Three-dimensional spin and hardcore-boson models
cond-mat.quant-gas
We study the stability of solid- and supersolid (SS) phases of a
three-dimensional spin- and a hardcore-Bose-Hubbard models on a body-centered
cubic lattice. To see the quantum effects on the stability of the SS phase, we
model the vacancies (interstitials) introduced in the solid, which are believed
responsible for the appearance of the SS phase, by spinwave bosons and adopt
the interaction between the condensed bosons as a criterion. A repulsive nature
of the low-energy effective interaction is the necessary condition for a
second-order solid-SS transition and, when this condition is met, normally the
SS phase is expected. In calculating the effective interaction, we use
expansions from the semiclassical- (i.e. large-S) and the Ising limit combined
with the ladder approximation. The impact of quantum fluctuations crucially
depends on the energy of the solid phase and that of the superfluid phase at
half filling. As an application to 4He, we study the parameter region in the
vicinity of the fitting parameter set given by Liu and Fisher. For this
parameters set, quantum fluctuations at the second order in 1/S destabilize the
solid phase, which is supposed to be stable within the mean field theory.
| arxiv topic:cond-mat.quant-gas |
arxiv_dataset-1565911.2479 | Arakelov theory of noncommutative arithmetic curves
math.NT math.RA
The purpose of this article is to initiate Arakelov theory in a
noncommutative setting. More precisely, we are concerned with Arakelov theory
of noncommutative arithmetic curves. Our first main result is an arithmetic
Riemann-Roch formula in this setup. We proceed with introducing the
Grothendieck group of arithmetic vector bundles on a noncommutative arithmetic
curve and show that there is a uniquely determined degree map, which we then
use to define a height function. We prove a duality theorem for this height.
| arxiv topic:math.NT math.RA |
arxiv_dataset-1566911.2579 | Zero Action on Perfect Crystals for U_q(G_2^{(1)})
math.QA math.CO
The actions of 0-Kashiwara operators on the $U'_q(G_2^{(1)})$-crystal $B_l$
in [Yamane S., J. Algebra 210 (1998), 440-486] are made explicit by using a
similarity technique from that of a $U'_q(D_4^{(3)})$-crystal. It is shown that
$\{B_l\}_{l\ge1}$ forms a coherent family of perfect crystals.
| arxiv topic:math.QA math.CO |
arxiv_dataset-1567911.2679 | Cables of thin knots and bordered Heegaard Floer homology
math.GT
We use bordered Floer homology to give a formula for the knot Floer homology
of any (p, pn+1)-cable of a thin knot K in terms of Delta_K(t), tau(K), p, and
n. We also give a formula for the Ozsvath-Szabo concordance invariant tau(K_{p,
pn+1}) in terms of tau(K), p, and n, and a formula for tau(K_{p,q}) for almost
all relatively prime p and q.
| arxiv topic:math.GT |
arxiv_dataset-1568911.2779 | Evidence of Magnetically Driven Structural Phase Transition in Parent
Compounds RFeAsO (R = La, Sm, Gd, Tb): study of low-temperature X-ray
diffraction
cond-mat.supr-con cond-mat.mtrl-sci
We report measurements of structural phase transition of four parent
compounds $R$FeAsO ($R$ = La, Sm, Gd, and Tb) by means of low-temperature X-ray
diffraction (XRD). Magnetic transition temperatures associated with Fe ions
($T_{N1}$) are also determined from the temperature dependence of resistivity.
As $R$ is changed from La, through Sm and Gd, to Tb, both the c-axis and a-axis
lattice constants decrease significantly. Meanwhile both the structural phase
transition temperature ($T_S$) and $T_{N1}$ decrease monotonously. It is also
found that the temperature gap between $T_S$ and $T_{N1}$ becomes smaller when
the distance between FeAs layer becomes shorter. This result is consistent with
magnetically driven structural phase transition and suggests that the
dimensionality have an important effect on the AFM ordering.
| arxiv topic:cond-mat.supr-con cond-mat.mtrl-sci |
arxiv_dataset-1569911.2879 | Field induced resistivity anisotropy in SrRuO3 films
cond-mat.str-el
SrRuO3 is an itinerant ferromagnet with orthorhombic structure and uniaxial
magnetocrystalline anisotropy - features expected to yield resistivity
anisotropy. Here we explore changes in the resistivity anisotropy of epitaxial
SrRuO3 films due to induced magnetization in the paramagnetic state by using
the planar Hall effect. We find that the effect of the induced magnetization on
the in-plane anisotropy is strongly angular dependent, and we provide a full
description of this behavior at 160 K for induced magnetization in the (001)
plane.
| arxiv topic:cond-mat.str-el |
arxiv_dataset-1570911.2979 | The representativity of pretzel knots
math.GT
In the present paper, we will show that a $(p,q,r)$-pretzel knot has the
representativity 3 if and only if $(p,q,r)$ is either $\pm(-2,3,3)$ or
$\pm(-2,3,5)$. We also show that a large algebraic knot has the
representativity less than or equal to 3.
| arxiv topic:math.GT |
arxiv_dataset-1571911.3079 | Mechanisms for the superconducting state from a one-particle derivation
of the BCS gap equations
cond-mat.supr-con
The BCS results for the superconducting gap $\Delta$ and $T_C$ are obtained
from a one-particle model. Superconductivity appears when the electronic energy
gains of the band structure surpass the energy needed for atomic vibrations or
magnetic moment oscillations. The vibration/oscillation amplitudes determine
the superconducting gap, and the Fermi surface is important for the
q-dependence. This permits for complementary interpretations of the parameters
for superconductivity and modeling of density-of-state effects. It also makes
the superconducting mechanism less exotic.
| arxiv topic:cond-mat.supr-con |
arxiv_dataset-1572911.3179 | On pointwise decay of linear waves on a Schwarzschild black hole
background
math.AP gr-qc math-ph math.MP
We prove sharp pointwise $t^{-3}$ decay for scalar linear perturbations of a
Schwarzschild black hole without symmetry assumptions on the data. We also
consider electromagnetic and gravitational perturbations for which we obtain
decay rates $t^{-4}$, and $t^{-6}$, respectively. We proceed by decomposition
into angular momentum $\ell$ and summation of the decay estimates on the
Regge-Wheeler equation for fixed $\ell$. We encounter a dichotomy: the decay
law in time is entirely determined by the asymptotic behavior of the
Regge-Wheeler potential in the far field, whereas the growth of the constants
in $\ell$ is dictated by the behavior of the Regge-Wheeler potential in a small
neighborhood around its maximum. In other words, the tails are controlled by
small energies, whereas the number of angular derivatives needed on the data is
determined by energies close to the top of the Regge-Wheeler potential. This
dichotomy corresponds to the well-known principle that for initial times the
decay reflects the presence of complex resonances generated by the potential
maximum, whereas for later times the tails are determined by the far field.
However, we do not invoke complex resonances at all, but rely instead on
semiclassical Sigal-Soffer type propagation estimates based on a Mourre bound
near the top energy.
| arxiv topic:math.AP gr-qc math-ph math.MP |
arxiv_dataset-1573911.3279 | An efficient method for computing the eigenfunctions of the dynamo
equation
astro-ph.IM
We present an elegant method of determining the eigensolutions of the
induction and the dynamo equation in a fluid embedded in a vacuum. The magnetic
field is expanded in a complete set of functions. The new method is based on
the biorthogonality of the adjoint electric current and the vector potential
with an inner product defined by a volume integral over the fluid domain. The
advantage of this method is that the velocity and the dynamo coefficients of
the induction and the dynamo equation do not have to be differentiated and thus
even numerically determined tabulated values of the coefficients produce
reasonable results. We provide test calculations and compare with published
results obtained by the classical treatment based on the biorthogonality of the
magnetic field and its adjoint. We especially consider dynamos with mean-field
coefficients determined from direct numerical simulations of the geodynamo and
compare with initial value calculations and the full MHD simulations.
| arxiv topic:astro-ph.IM |
arxiv_dataset-1574911.3379 | Transitional random matrix theory nearest-neighbor spacing distributions
math-ph math.MP
This paper presents a study of the properties of a matrix model that was
introduced to describe transitions between all Wigner surmises of Random Matrix
theory. New results include closed-form exact analytical expressions for the
transitional probability density functions, as well as suitable analytical
approximations for cases not amenable to explicit representation.
| arxiv topic:math-ph math.MP |
arxiv_dataset-1575911.3479 | CP phase of nonuniversal $Z'$ on $\sin\phi^{J/\Psi \phi}_s$ and T-odd
observables of $\bar B_{q}\to V_{q} \ell^{+} \ell^{-}$
hep-ph
The evidence of a large CP phase has been shown by CDF and D{\O}
collaborations in the time-dependent CP asymmetry (CPA) of $B_s\to J/\Psi \phi$
decay, where the nonvanished CPA clearly implies the existence of a
non-Kobayashi-Maskawa phase in $b\to s$ transition. We study the new phases
originated by the extra family dependent $U(1)'$ model and examine their impact
on $\hat{T}$ or CP violating observables in $\bar B_q\to V_q \ell^{+} \ell^{-}$
decays with $V_q=K^* (\phi)$. Adopting the constraints from the current data of
$\Delta m_s$ and the branching ratios for $\bar B_s\to \mu^+ \mu^-$ and $\bar
B_q\to V_q\ell^+ \ell^-$, we find that $\phi^{J/\Psi\phi}_s=-(0.26\pm 0.22)$
and the T-odd observables of above 10% in the decay chain $\bar B_q\to V_q(\to
K\pi [KK]) \ell^+ \ell^-$ can be achieved. In addition, we demonstrate that the
longitudinal and transverse polarizations of $K^*$ and the up-down asymmetry of
$K$ in the same decay chain are also sensitive to the $Z'$-mediated effects.
| arxiv topic:hep-ph |
arxiv_dataset-1576911.3579 | Finding Traps in Non-linear Spin Arrays
quant-ph
Precise knowledge of the Hamiltonian of a system is a key to many of its
applications. Tasks such state transfer or quantum computation have been well
studied with a linear chain, but hardly with systems, which do not possess a
linear structure. While this difference does not disturb the end-to-end
dynamics of a single excitation, the evolution is significantly changed in
other subspaces. Here we quantify the difference between a linear chain and a
pseudo-chain, which have more than one spin at some site (block). We show how
to estimate a number of all spins in the system and the intra-block coupling
constants. We also suggest how it is possible to eliminate excitations trapped
in such blocks, which may disturb the state transfer. Importantly, one uses
only at-ends data and needs to be able to put the system to either the
maximally magnetized or the maximally mixed state. This can obtained by
controlling a global decoherence parameter, such as temperature.
| arxiv topic:quant-ph |
arxiv_dataset-1577911.3679 | Dickson's conjecture on $Z^n$--An equivalent form of Green-Tao's
conjecture
math.GM
In [1], we give Dickson's conjecture on $N^n$. In this paper, we further give
Dickson's conjecture on $Z^n$ and obtain an equivalent form of Green-Tao's
conjecture [2]. Based on our work, it is possible to establish a general theory
that several multivariable integral polynomials on $Z^n$ represent
simultaneously prime numbers for infinitely many integral points and generalize
the analogy of Chinese Remainder Theorem in [3].
Dans [1], nous donnons la conjecture de Dickson sur $N^n$. Dans ce document,
en outre nous accordons une conjecture de Dickson sur $Z^n$ et obtenons une
forme \'{e}quivalent de conjecture de Green-Tao [2]. Sur la base de nos
travaux, il est possible d'\'{e}tablir une th\'{e}orie g\'{e}n\'{e}rale que
plusieurs polyn\^{o}mes int\'{e}graux multivariables sur $Z^n$ repr\'{e}sentent
simultan\'{e}ment les nombres premiers pour un nombre infini de points entiers
et de g\'{e}n\'{e}raliser les l'analogie de Th\'{e}or\`{e}me des Restes Chinois
dans [3].
| arxiv topic:math.GM |
arxiv_dataset-1578911.3779 | The Skeleton: Connecting Large Scale Structures to Galaxy Formation
astro-ph.CO astro-ph.GA
We report on two quantitative, morphological estimators of the filamentary
structure of the Cosmic Web, the so-called global and local skeletons. The
first, based on a global study of the matter density gradient flow, allows us
to study the connectivity between a density peak and its surroundings, with
direct relevance to the anisotropic accretion via cold flows on galactic halos.
From the second, based on a local constraint equation involving the
derivatives of the field, we can derive predictions for powerful statistics,
such as the differential length and the relative saddle to extrema counts of
the Cosmic web as a function of density threshold (with application to
percolation of structures and connectivity), as well as a theoretical framework
to study their cosmic evolution through the onset of gravity-induced
non-linearities.
| arxiv topic:astro-ph.CO astro-ph.GA |
arxiv_dataset-1579911.3879 | Star Formation in Dwarf Galaxies of the Nearby Centaurus A Group
astro-ph.GA
We present Halpha narrow-band imaging of 17 dwarf irregular galaxies (dIs) in
the nearby Centaurus A Group. Although all large galaxies of the group have a
current or recent enhanced star formation episode, the dIs have normal star
formation rates and do not contain a larger fraction of dwarf starbursts than
other nearby groups. Relative distances between dIs and larger galaxies of the
group can be computed in 3D since most of them have now fairly accurately known
distances. We find that the dI star formation rates do not depend on local
environment, and in particular they do not show any correlation with the
distance of the dI to the nearest large galaxy of the group. There is a clear
morphology-density relation in the Centaurus A Group, similarly to the Sculptor
and Local Groups, in the sense that dEs/dSphs tend to be at small distances
from the more massive galaxies of the group, while dIs are on average at larger
distances. We find four transition dwarfs in the Group, dwarfs that show
characteristics of both dE/dSphs and dIs, and which contain cold gas but no
current star formation. Interestingly the transition dwarfs have an average
distance to the more massive galaxies which is intermediate between those of
the dEs/dSphs and dIs, and which is quite large: 0.54 +- 0.31 Mpc. This large
distance poses some difficulty for the most popular scenarios proposed for
transforming a dI into a dE/dSph (ram-pressure with tidal stripping or galaxy
harassment). If the observed transition dwarfs are indeed missing links between
dIs and dE/dSphs, their relative isolation makes it less likely to have been
produced by these mechanisms. We propose that an inhomogeneous IGM containing
higher density clumps would be able to ram-pressure stripped the dIs at such
large distances.
| arxiv topic:astro-ph.GA |
arxiv_dataset-1580911.3979 | Making the road by searching - A search engine based on Swarm
Information Foraging
cs.IR cs.HC
Search engines are nowadays one of the most important entry points for
Internet users and a central tool to solve most of their information needs.
Still, there exist a substantial amount of users' searches which obtain
unsatisfactory results. Needless to say, several lines of research aim to
increase the relevancy of the results users retrieve. In this paper the authors
frame this problem within the much broader (and older) one of information
overload. They argue that users' dissatisfaction with search engines is a
currently common manifestation of such a problem, and propose a different angle
from which to tackle with it. As it will be discussed, their approach shares
goals with a current hot research topic (namely, learning to rank for
information retrieval) but, unlike the techniques commonly applied in that
field, their technique cannot be exactly considered machine learning and,
additionally, it can be used to change the search engine's response in
real-time, driven by the users behavior. Their proposal adapts concepts from
Swarm Intelligence (in particular, Ant Algorithms) from an Information Foraging
point of view. It will be shown that the technique is not only feasible, but
also an elegant solution to the stated problem; what's more, it achieves
promising results, both increasing the performance of a major search engine for
informational queries, and substantially reducing the time users require to
answer complex information needs.
| arxiv topic:cs.IR cs.HC |
arxiv_dataset-1581911.4079 | Slow plasma dynamo driven by electric current helicity in non-compact
Riemann surfaces of negative curvature
physics.plasm-ph
Boozer addressed the role of magnetic helicity in dynamos [Phys Fluids
\textbf{B},(1993)]. He pointed out that the magnetic helicity conservation
implies that the dynamo action is more easily attainable if the electric
potential varies over the surface of the dynamo. This provided us with
motivation to investigate dynamos in Riemannian curved surfaces [Phys Plasmas
\textbf{14}, (2007);\textbf{15} (2008)]. Thiffeault and Boozer [Phys Plasmas
(2003)] discussed the onset of dissipation in kinematic dynamos. When curvature
is constant and negative, a simple simple laminar dynamo solution is obtained
on the flow topology of a Poincare disk, whose Gauss curvature is $K=-1$. By
considering a laminar plasma dynamo [Wang et al, Phys Plasmas (2002)] the
electric current helicity ${\lambda}\approx{2.34m^{-1}}$ for a Reynolds
magnetic number of $Rm\approx{210}$ and a growth rate of magnetic field
$|{\gamma}|\approx{0.022}$. Negative constant curvature non-compact
$\textbf{H}^{2}$, has also been used in one-component electron 2D plasma by
Fantoni and Tellez (Stat Phys, (2008)). Chicone et al (CMP (1997)) showed fast
dynamos can be supported in compact $\textbf{H}^{2}$. PACS: 47.65.Md. Key-word:
dynamo plasma.
| arxiv topic:physics.plasm-ph |
arxiv_dataset-1582911.4179 | Estimation of characteristic size of ferromagnetic clusters forming
above T$_C$ in Nd$_{0.75}$Ba$_{0.25}$MnO$_3$ manganite
cond-mat.mes-hall cond-mat.str-el
We present the data on depolarization of polarized neutron beam and second
harmonic of magnetization ($M_2$) for Nd$_{1-x}$Ba$_x$MnO$_3$ ($x$ = 0.23, the
Curie temperature $T_C \approx$ 124 K; $x$ = 0.25, $T_C \approx$ 129 K)
manganites. The depolarization starts to develop below $T$* $\approx$ 147 K $>
T_C$ for both samples, being larger in x = 0.25 compound. This evidences the
arising of a ferromagnetic (F) cluster phase below $T$* and a growth of its
relative volume fraction with increasing doping concentration that agrees with
the previously published results of $M_2$ study. A characteristic size of the F
clusters and their concentration are estimated combining the neutron
depolarization and $M_2$ data for $x$ = 0.25 manganite.
| arxiv topic:cond-mat.mes-hall cond-mat.str-el |
arxiv_dataset-1583911.4279 | Gevrey regularizing effect of the Cauchy problem for non-cutoff
homogeneous Kac's equation
math.AP
In this work, we consider a spatially homogeneous Kac's equation with a non
cutoff cross section. We prove that the weak solution of the Cauchy problem is
in the Gevrey class for positive time. This is a Gevrey regularizing effect for
non smooth initial datum. The proof relies on the Fourier analysis of Kac's
operators and on an exponential type mollifier.
| arxiv topic:math.AP |
arxiv_dataset-1584911.4379 | Black Holes in Gravity with Conformal Anomaly and Logarithmic Term in
Black Hole Entropy
hep-th gr-qc
We present a class of exact analytic and static, spherically symmetric black
hole solutions in the semi-classical Einstein equations with Weyl anomaly. The
solutions have two branches, one is asymptotically flat and the other
asymptotically de Sitter. We study thermodynamic properties of the black hole
solutions and find that there exists a logarithmic correction to the well-known
Bekenstein-Hawking area entropy. The logarithmic term might come from non-local
terms in the effective action of gravity theories. The appearance of the
logarithmic term in the gravity side is quite important in the sense that with
this term one is able to compare black hole entropy up to the subleading order,
in the gravity side and in the microscopic statistical interpretation side.
| arxiv topic:hep-th gr-qc |
arxiv_dataset-1585911.4479 | Physical characterisation of southern massive star-forming regions using
Parkes NH$_3$ observations
astro-ph.SR astro-ph.GA
We have undertaken a Parkes ammonia spectral line study, in the lowest two
inversion transitions, of southern massive star formation regions, including
young massive candidate protostars, with the aim of characterising the earliest
stages of massive star formation. 138 sources from the submillimetre continuum
emission studies of Hill et al., were found to have robust (1,1) detections,
including two sources with two velocity components, and 102 in the (2,2)
transition.
We determine the ammonia line properties of the sources: linewidth, flux
density, kinetic temperature, NH$_3$ column density and opacity, and revisit
our SED modelling procedure to derive the mass for 52 of the sources. By
combining the continuum emission information with ammonia observations we
substantially constrain the physical properties of the high-mass clumps. There
is clear complementarity between ammonia and continuum observations for
derivations of physical parameters.
The MM-only class, identified in the continuum studies of Hill et al.,
display smaller sizes, mass and velocity dispersion and/or turbulence than
star-forming clumps, suggesting a quiescent prestellar stage and/or the
formation of less massive stars.
| arxiv topic:astro-ph.SR astro-ph.GA |
arxiv_dataset-1586911.4579 | On the renormalization of gauge theories in curved space-time
hep-th
We consider the renormalization of general gauge theories on curved
space-time background, with the main assumption being the existence of a
gauge-invariant and diffeomorphism invariant regularization. Using the
Batalin-Vilkovisky (BV) formalism one can show that the theory possesses gauge
invariant and diffeomorphism invariant renormalizability at quantum level, up
to an arbitrary order of the loop expansion. Starting from this point we
discuss the locality of the counterterms and the general prescription for
constructing the power-counting renormalizable theories on curved background.
| arxiv topic:hep-th |
arxiv_dataset-1587911.4679 | Gain/loss asymmetry in time series of individual stock prices and its
relationship to the leverage effect
q-fin.ST
Previous research has shown that for stock indices, the most likely time
until a return of a particular size has been observed is longer for gains than
for losses. We establish that this so-called gain/loss asymmetry is present
also for individual stocks and show that the phenomenon is closely linked to
the well-known leverage effect -- in the EGARCH model and a modified retarded
volatility model, the same parameter that governs the magnitude of the leverage
effect also governs the gain/loss asymmetry.
| arxiv topic:q-fin.ST |
arxiv_dataset-1588911.4779 | On the Dark Matter Solutions to the Cosmic Ray Lepton Puzzle
astro-ph.CO
Recent measurements of cosmic ray leptons by PAMELA, ATIC, HESS and Fermi
revealed interesting excesses. Many authors suggested particle Dark Matter (DM)
annihilations could be at the origin of these effects. In this paper, we
critically assess this interpretation by reviewing some results questioning the
naturalness and robustness of such an interpretation. Natural values for the DM
particle parameters lead to a poor leptons production so that models often
require signal enhancement effects that we constrain here. Considering DM
annihilations are likely to produce antiprotons as well, we use the PAMELA
antiproton to proton ratio measurements to constrain a possible exotic
contribution. We also consider the possibility of an enhancement due to a
nearby clump of DM. This scenario appears unlikely when compared to the
state-of-the-art cosmological N-body simulations. We conclude that the bulk of
the observed signals most likely has no link with DM and is rather a new, yet
unconsidered source of background for searches in these channels.
| arxiv topic:astro-ph.CO |
arxiv_dataset-1589911.4879 | Layer Oriented Wavefront sensor for MAD on Sky operations
astro-ph.IM
The Multiconjugate Adaptive optics Demonstrator (MAD) has successfully
demonstrated on sky both Star Oriented (SO) and Layer Oriented (LO)
multiconjugate adaptive optics techniques. While SO has been realized using 3
Shack-Hartmann wavefront sensors (WFS), we designed a multi-pyramid WFS for the
LO. The MAD bench accommodates both WFSs and a selecting mirror allows choosing
which sensor to use. In the LO approach up to 8 pyramids can be placed on as
many reference stars and their light is co-added optically on two different
CCDs conjugated at ground and to an high layer. In this paper we discuss LO
commissioning phase and on sky operations.
| arxiv topic:astro-ph.IM |
arxiv_dataset-1590911.4979 | Monoidal 2-structure of Bimodule Categories
math.QA math.CT
We define a notion of tensor product of bimodule categories and prove that
with this product the 2-category of C-bimodule categories for fixed tensor C is
a monoidal 2-category in the sense of Kapranov and Voevodsky. We then provide a
monoidal-structure preserving 2-equivalence between the 2-category of
C-bimodule categories and Z(C)-module categories (module categories over the
center). For finite group G we show that de-equivariantization is equivalent to
tensor product over category Rep(G) of finite dimensional representations. We
derive Rep(G)-module fusion rules and determine the group of invertible
irreducible Rep(G)-module categories extending earlier results for abelian
groups.
| arxiv topic:math.QA math.CT |
arxiv_dataset-1591911.5079 | On roots of Dehn twists
math.GT math.GR
Margalit and Schleimer constructed nontrivial roots of the Dehn twist about a
nonseparating curve. We prove that the conjugacy classes of roots of the Dehn
twist about a nonseparating curve correspond to the conjugacy classes of
periodic maps with certain conditions. Futhermore, we give data set which
determine the conjugacy class of a root. As a consequence, we can find the
minimum degree and the maximum degree, and show that the degree must be odd.
Also, we give Dehn twist expression of the root of degree 3.
| arxiv topic:math.GT math.GR |
arxiv_dataset-1592911.5179 | Traveling waves and homogeneous fragmentation
math.PR math.AG
We formulate the notion of the classical
Fisher-Kolmogorov-Petrovskii-Piscounov (FKPP) reaction diffusion equation
associated with a homogeneous conservative fragmentation process and study its
traveling waves. Specifically, we establish existence, uniqueness and
asymptotics. In the spirit of classical works such as McKean [Comm. Pure Appl.
Math. 28 (1975) 323-331] and [Comm. Pure Appl. Math. 29 (1976) 553-554], Neveu
[In Seminar on Stochastic Processes (1988) 223-242 Birkh\"{a}user] and Chauvin
[Ann. Probab. 19 (1991) 1195-1205], our analysis exposes the relation between
traveling waves and certain additive and multiplicative martingales via laws of
large numbers which have been previously studied in the context of
Crump-Mode-Jagers (CMJ) processes by Nerman [Z. Wahrsch. Verw. Gebiete 57
(1981) 365-395] and in the context of fragmentation processes by Bertoin and
Martinez [Adv. in Appl. Probab. 37 (2005) 553-570] and Harris, Knobloch and
Kyprianou [Ann. Inst. H. Poincar\'{e} Probab. Statist. 46 (2010) 119-134]. The
conclusions and methodology presented here appeal to a number of concepts
coming from the theory of branching random walks and branching Brownian motion
(cf. Harris [Proc. Roy. Soc. Edinburgh Sect. A 129 (1999) 503-517] and Biggins
and Kyprianou [Electr. J. Probab. 10 (2005) 609-631]) showing their
mathematical robustness even within the context of fragmentation theory.
| arxiv topic:math.PR math.AG |
arxiv_dataset-1593911.5279 | Duality symmetry of BFKL equation: reggeized gluons vs color dipoles
hep-ph
We show that the duality symmetry of the BFKL equation can be interpreted as
a symmetry under rotation of the BFKL Kernel in the transverse space from
s-channel (color dipole model) to t-channel (reggeized gluon formulation). We
argue that the duality symmetry holds also in the non-forward case due to a
very special structure of the non-forward BFKL Kernel, which can be written as
a sum of three forward BFKL Kernels. The duality symmetry is established by
identifying the dual coordinates with the transverse coordinates of a
non-diagonal dipole scattered off the target.
| arxiv topic:hep-ph |
arxiv_dataset-1594911.5379 | High efficiency Four-Wave Mixing in a five-level atomic System based on
the two electromagnetically induced transparency
physics.atom-ph
We have analyzed a five-level $\wedge$-configuration Four-Wave Mixing (FWM)
scheme for obtaining a high-efficiency FWM based on the two electromagnetically
induced transparency. We find that the maximum FWM efficiency is nearly 30%,
which is orders of magnitude larger than previous schemes based on the two
electromagnetically induced transparency. Our scheme may provide a new
possibility for technological applications such as nonlinear spectroscopy at
very low light intensity, quantum single-photon nonlinear optics and quantum
information science.
| arxiv topic:physics.atom-ph |
arxiv_dataset-1595911.5479 | Quark fluids in heavy ion collisions
nucl-th physics.pop-ph
We give a pedagogical introduction (suitable to upper level physics
undergraduates) to the field of ultrarelativistic heavy ion collisions. We pay
particular attention to our understanding of the thermodynamic and hydrodynamic
properties of the matter created in heavy ion collisions at RHIC energies.
| arxiv topic:nucl-th physics.pop-ph |
arxiv_dataset-1596911.5579 | Asymptotic behavior of prices of path dependent options
q-fin.PR q-fin.CP
In this paper, we give a numerical method for pricing long maturity, path
dependent options by using the Markov property for each underlying asset. This
enables us to approximate a path dependent option by using some kinds of plain
vanillas. We give some examples whose underlying assets behave as some popular
Levy processes. Moreover, we give some payoffs and functions used to
approximate them.
| arxiv topic:q-fin.PR q-fin.CP |
arxiv_dataset-1597911.5679 | The Andyrchy-BUST experiment: primary spectrum and composition around
the knee
astro-ph.HE
The main goal of the Andyrchy-BUST experiment is to study the primary cosmic
rays spectrum and composition around the knee. The experimental data on the
knee, as observed in the electromagnetic and high energy muon components, are
presented. The electromagnetic component in our experiment is measured using
the "Andyrchy" EAS array. High energy muon component (with 230 GeV threshold
energy of muons) is measured using the Baksan Underground Scintillation
Telescope (BUST). The location of the "Andyrchy" right above the BUST gives us
a possibility for simultaneous measurements of both EAS components.
| arxiv topic:astro-ph.HE |
arxiv_dataset-1598912.0049 | Paramodular Cusp Forms
math.NT
We classify Siegel modular cusp forms of weight two for the paramodular group
K(p) for primes p< 600. We find that weight two Hecke eigenforms beyond the
Gritsenko lifts correspond to certain abelian varieties defined over the
rationals of conductor p. The arithmetic classification is in a companion
article by A. Brumer and K. Kramer. The Paramodular Conjecture, supported by
these computations and consistent with the Langlands philosophy and the work of
H. Yoshida, is a partial extension to degree 2 of the Shimura-Taniyama
Conjecture. These nonlift Hecke eigenforms share Euler factors with the
corresponding abelian variety $A$ and satisfy congruences modulo \ell with
Gritsenko lifts, whenever $A$ has rational \ell-torsion.
| arxiv topic:math.NT |
arxiv_dataset-1599912.0149 | Robust Cooperative Spectrum Sensing for Disaster Relief Networks in
Correlated Environments
cs.NI cs.DC
Disaster relief networks are designed to be adaptable and resilient so to
encompass the demands of the emergency service. Cognitive Radio enhanced ad-hoc
architecture has been put forward as a candidate to enable such networks.
Spectrum sensing, the cornerstone of the Cognitive Radio paradigm, has been the
focus of intensive research, from which the main conclusion was that its
performance can be greatly enhanced through the use of cooperative sensing
schemes. To apply the Cognitive Radio paradigm to Ad-hoc disaster relief
networks, the design of effective cooperative spectrum sensing schemes is
essential. In this paper we propose a cluster based orchestration cooperative
sensing scheme, which adapts to the cluster nodes surrounding radio environment
state as well as to the degree of correlation observed between those nodes. The
proposed scheme is given both in a centralized as well as in a decentralized
approach. In the centralized approach, the cluster head controls and adapts the
distribution of the cluster sensing nodes according to the monitored spectrum
state. While in the decentralized approach, each of the cluster nodes decides
which spectrum it should monitor, according to the past local sensing decisions
of the cluster nodes. The centralized and decentralized schemes can be combined
to achieve a more robust cooperative spectrum sensing scheme. The proposed
scheme performance is evaluated through a framework, which allows measuring the
accuracy of the spectrum sensing cooperative scheme by measuring the error in
the estimation of the monitored spectrum state. Through this evaluation it is
shown that the proposed scheme outperforms the case where the choice of which
spectrum to sense is done without using the knowledge obtained in previous
sensing iterations, i.e. a implementation of a blind Round Robin scheme.
| arxiv topic:cs.NI cs.DC |
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