Latest Papers in Condensed Matter Physics

Statistical Mechanics

Bootstrapping Mixed Correlators in Three-Dimensional Cubic Theories (1810.10015v4)

Stefanos R. Kousvos, Andreas Stergiou

2018-10-23

Three-dimensional theories with cubic symmetry are studied using the machinery of the numerical conformal bootstrap. Crossing symmetry and unitarity are imposed on a set of mixed correlators, and various aspects of the parameter space are probed for consistency. An isolated allowed region in parameter space is found under certain assumptions involving pushing operator dimensions above marginality, indicating the existence of a conformal field theory in this region. The obtained results have possible applications for ferromagnetic phase transitions as well as structural phase transitions in crystals. They are in tension with previous expansion results, as noticed already in earlier work.

Assisted work distillation (1811.12329v2)

Benjamin Morris, Ludovico Lami, Gerardo Adesso

2018-11-29

We study the process of assisted work distillation. This scenario arises when two parties share a bipartite quantum state and their task is to locally distil the optimal amount of work when one party is restricted to thermal operations whereas the other can perform general quantum operations and they are allowed to communicate classically. We demonstrate that this question is intimately related to the distillation of classical/quantum correlations. In particular, we show that the advantage of one party performing global measurements over many copies of is related to the non-additivity of the entanglement of formation. We also show that there may exist work bound in the quantum correlations of the state that is only extractable under the wider class of local Gibbs-preserving operations.

Haar systems, KMS states on von Neumann algebras and -algebras on dynamically defined groupoids and Noncommutative Integration (1711.04572v6)

Gilles G. de Castro, Artur O. Lopes, Gabriel Mantovani

2017-11-13

We analyse certain Haar systems associated to groupoids obtained by certain natural equivalence relations of dynamical nature on sets like , , , or , where is the unitary circle. We also describe properties of transverse functions, quasi-invariant probabilities and KMS states for some examples of von Neumann algebras (and also -Algebras) associated to these groupoids. We relate some of these KMS states with Gibbs states of Thermodynamic Formalism. While presenting new results, we will also describe in detail several examples and basic results on the above topics. In other words it is also a survey paper. Some known results on non-commutative integration are presented, more precisely, the relation of transverse measures, cocycles and quasi-invariant probabilities. We describe the results in a language which is more familiar to people in Dynamical Systems. Our intention is to study Haar systems, quasi-invariant probabilities and von Neumann algebras as a topic on measure theory (intersected with ergodic theory) avoiding questions of algebraic nature (which, of course, are also extremely important).

Fokker-Planck equations for time-delayed systems via Markovian Embedding (1903.02322v1)

Sarah A. M. Loos, Sabine H. L. Klapp

2019-03-06

For stochastic systems with discrete time delay, the Fokker-Planck equation (FPE) of the one-time probability density function (PDF) does not provide a complete, self-contained probabilistic description, as it explicitly involves the two-time PDF. We here introduce a new approach to find a Fokker-Planck description by using a Markovian embedding technique and a subsequent limiting procedure. On this way, we derive a hierarchy of FPEs whose first member is the well-known FPE for the one-time PDF. Moreover, as second member we obtain a new equation for the two-time PDF. The latter gives the correlation between the present and the delayed time and is thus a central quantity in the description of these time-delayed, non-Markovian systems. From a conceptual point of view, our approach yields interesting insight into both, the physical meaning, and the mathematical structure of delayed processes. We further propose a possible approximation scheme basing on this new equation.

Producing suprathermal tails in the stationary velocity distribution (1903.02312v1)

Thibaut Demaerel, Wojciech De Roeck, Christian Maes