Latest Research Papers In Condensed Matter Physics | (Cond-Mat.Stat-Mech) 2019-05-12
Statistical Mechanics
Branes and Categorifying Integrable Lattice Models (1806.02821v6)
Meer Ashwinkumar, Meng-Chwan Tan, Qin Zhao
2018-06-07
We elucidate how integrable lattice models described by Costello's 4d Chern-Simons theory can be realized via a stack of D4-branes ending on an NS5-brane in type IIA string theory, with D0-branes on the D4-brane worldvolume sourcing a meromorphic RR 1-form, and fundamental strings forming the lattice. This provides us with a nonperturbative integration cycle for the 4d Chern-Simons theory, and by applying T- and S-duality, we show how the R-matrix, the Yang-Baxter equation and the Yangian can be categorified, that is, obtained via the Hilbert space of a 6d gauge theory.
Fundamentals of spreading processes in single and multilayer complex networks (1804.08777v2)
Guilherme Ferraz de Arruda, Francisco A. Rodrigues, Yamir Moreno
2018-04-23
Spreading processes have been largely studied in the literature, both analytically and by means of large-scale numerical simulations. These processes mainly include the propagation of diseases, rumors and information on top of a given population. In the last two decades, with the advent of modern network science, we have witnessed significant advances in this field of research. Here we review the main theoretical and numerical methods developed for the study of spreading processes on complex networked systems. Specifically, we formally define epidemic processes on single and multilayer networks and discuss in detail the main methods used to perform numerical simulations. Throughout the review, we classify spreading processes (disease and rumor models) into two classes according to the nature of time: (i) continuous-time and (ii) cellular automata approach, where the second one can be further divided into synchronous and asynchronous updating schemes. Our revision includes the heterogeneous mean-field, the quenched-mean field, and the pair quenched mean field approaches, as well as their respective simulation techniques, emphasizing similarities and differences among the different techniques. The content presented here offers a whole suite of methods to study epidemic-like processes in complex networks, both for researchers without previous experience in the subject and for experts.
Sensing with the harmonic oscillator (1905.02612v2)
Gerard P. Conangla
2019-05-06
A system obeying the harmonic oscillator equation of motion can be used as a force or proper acceleration sensor. In this short review we derive analytical expressions for the sensitivity of such sensors in a range of different situations, considering noise of thermal and measurement origins and a formalism for dealing with oscillators whose natural frequency
jitters. A special case where the sensitivity can be improved beyond the standard expressions and some applications with examples are also discussed.
Universality in the time correlations of the long-range 1d Ising model (1904.05595v2)
Federico Corberi, Eugenio Lippiello, Paolo Politi
2019-04-11
The equilibrium and nonequilibrium properties of ferromagnetic systems may be affected by the long-range nature of the coupling interaction. Here we study the phase separation process of a one-dimensional Ising model in the presence of a power-law decaying coupling,
with
, and we focus on the two-time autocorrelation function
. We find that it obeys the scaling form
, where
is the typical domain size at time
, and where
can only be of two types. For
, when domain walls diffuse freely,
, when domain walls dynamics is driven,
for
, is
in the nn universality class (
) and
for
A lower bound to the thermal diffusivity of insulators (1905.03551v1)
Kamran Behnia, Aharon Kapitulnik
2019-05-09
It has been known for decades that thermal conductivity of insulating crystals becomes proportional to the inverse of temperature when the latter is comparable to or higher than the Debye temperature. This behavior has been understood as resulting from Umklapp scattering among phonons. We put under scrutiny the magnitude of the thermal diffusion constant in this regime and find that it does not fall below a threshold set by the square of sound velocity times the Planckian time (
). The conclusion, based on scrutinizing the ratio in cubic crystals with high thermal resistivity, appears to hold even in glasses where Umklapp events are not conceivable. Explaining this boundary, reminiscent of a recently-noticed limit for charge transport in metals, is a challenge to theory.
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