We study the quantum-to-classical transition in a chaotic system surrounded by a diffusive environment. First, we analyze the emergence of classicality when it is monitored by the Renyi entropy, a measure of the entanglement of a system with its environment. We show that the Renyi entropy has a transition from quantum to classical behavior that scales with heff2D, where heff is the effective Planck constant and D is the strength of the noise. However, it was recently shown that a different scaling law controls the quantum-to-classical transition when it is measured comparing the corresponding phase-space distributions. Then, we discuss the meaning of both scalings in the precise definition of a frontier between the classical and quantum behaviors. Finally, we show that there are quantum coherences that the Renyi entropy is unable to detect, which questions its use in studies of decoherence.We study the quantum-to-classical transition in a chaotic system surrounded by a diffusive environment. First, we analyze the emergence of classicality when it is monitored by the Renyi entropy, a measure of the entanglement of a system with its environment. We show that the Renyi entropy has a transition from quantum to classical behavior that scales with heff2D, where heff is the effective Planck constant and D is the strength of the noise. However, it was recently shown that a different scaling law controls the quantum-to-classical transition when it is measured comparing the corresponding phase-space distributions. Then, we discuss the meaning of both scalings in the precise definition of a frontier between the classical and quantum behaviors. Finally, we show that there are quantum coherences that the Renyi entropy is unable to detect, which questions its use in studies of decoherence.

arXiv:0810.5740Physical Review EFeb 27, 200910 citations

THERMODYNAMIC DETECTION OF QUANTUM PHASE TRANSITIONS

Michael Kruse, H. G. Miller, Angelo Plastino +1 more

Mar 1, 20110 citations

Detecting Quantum Phase Transitions using Classical Noises

Yan Chen, Yinchen He

Bulletin of the American Physical SocietyMar 1, 20120 citations

Detecting classical phase transitions with Renyi mutual information

Jason Iaconis, Stephen Inglis, Ann B. Kallin +1 more

By developing a method to represent the Renyi entropies via a replica trick on classical statistical mechanical systems, we introduce a procedure to calculate the Renyi mutual information (RMI) in any Monte Carlo simulation. Through simulations on several classical models, we demonstrate that the RMI can detect finite-temperature critical points, and even identify their universality class, without knowledge of an order parameter or other thermodynamic estimators. Remarkably, in addition to critical points mediated by symmetry breaking, the RMI is able to detect topological vortex-unbinding transitions, as we explicitly demonstrate on simulations of the $XY$ model.By developing a method to represent the Renyi entropies via a replica trick on classical statistical mechanical systems, we introduce a procedure to calculate the Renyi mutual information (RMI) in any Monte Carlo simulation. Through simulations on several classical models, we demonstrate that the RMI can detect finite-temperature critical points, and even identify their universality class, without knowledge of an order parameter or other thermodynamic estimators. Remarkably, in addition to critical points mediated by symmetry breaking, the RMI is able to detect topological vortex-unbinding transitions, as we explicitly demonstrate on simulations of the $XY$ model.

arXiv:1210.2403Physical Review BMay 28, 201356 citations

Rényi entropy perspective on topological order in classical toric code models

Johannes Helmes, Jean-Marie Stéphan, Simon Trebst

Concepts of information theory are increasingly used to characterize collective phenomena in condensed matter systems, such as the use of entanglement entropies to identify emergent topological order in interacting quantum many-body systems. Here, we employ classical variants of these concepts, in particular R\'enyi entropies and their associated mutual information, to identify topological order in classical systems. Like for their quantum counterparts, the presence of topological order can be identified in such classical systems via a universal, subleading contribution to the prevalent volume and boundary laws of the classical R\'enyi entropies. We demonstrate that an additional subleading $O(1)$ contribution generically arises for all R\'enyi entropies ${S}^{(n)}$ with $n\ensuremath{\ge}2$ when driving the system towards a phase transition, e.g., into a conventionally ordered phase. This additional subleading term, which we dub connectivity contribution, tracks back to partial subsystem ordering and is proportional to the number of connected parts in a given bipartition. Notably, the Levin-Wen summation scheme, typically used to extract the topological contribution to the R\'enyi entropies, does not fully eliminate this additional connectivity contribution in this classical context. This indicates that the distillation of topological order from R\'enyi entropies requires an additional level of scrutiny to distinguish topological from nontopological $O(1)$ contributions. This is also the case for quantum systems, for which we discuss which entropies are sensitive to these connectivity contributions. We showcase these findings by extensive numerical simulations of a classical variant of the toric code model, for which we study the stability of topological order in the presence of a magnetic field and at finite temperatures from a R\'enyi entropy perspective.Concepts of information theory are increasingly used to characterize collective phenomena in condensed matter systems, such as the use of entanglement entropies to identify emergent topological order in interacting quantum many-body systems. Here, we employ classical variants of these concepts, in particular R\'enyi entropies and their associated mutual information, to identify topological order in classical systems. Like for their quantum counterparts, the presence of topological order can be identified in such classical systems via a universal, subleading contribution to the prevalent volume and boundary laws of the classical R\'enyi entropies. We demonstrate that an additional subleading $O(1)$ contribution generically arises for all R\'enyi entropies ${S}^{(n)}$ with $n\ensuremath{\ge}2$ when driving the system towards a phase transition, e.g., into a conventionally ordered phase. This additional subleading term, which we dub connectivity contribution, tracks back to partial subsystem ordering and is proportional to the number of connected parts in a given bipartition. Notably, the Levin-Wen summation scheme, typically used to extract the topological contribution to the R\'enyi entropies, does not fully eliminate this additional connectivity contribution in this classical context. This indicates that the distillation of topological order from R\'enyi entropies requires an additional level of scrutiny to distinguish topological from nontopological $O(1)$ contributions. This is also the case for quantum systems, for which we discuss which entropies are sensitive to these connectivity contributions. We showcase these findings by extensive numerical simulations of a classical variant of the toric code model, for which we study the stability of topological order in the presence of a magnetic field and at finite temperatures from a R\'enyi entropy perspective.

arXiv:1507.04682Physical Review BSep 24, 20159 citations

XY

model.

O(1)

contribution generically arises for all R\'enyi entropies

{S}^{(n)}

with $n\ensuremath{\ge}2$ when driving the system towards a phase transition, e.g., into a conventionally ordered phase. This additional subleading term, which we dub connectivity contribution, tracks back to partial subsystem ordering and is proportional to the number of connected parts in a given bipartition. Notably, the Levin-Wen summation scheme, typically used to extract the topological contribution to the R\'enyi entropies, does not fully eliminate this additional connectivity contribution in this classical context. This indicates that the distillation of topological order from R\'enyi entropies requires an additional level of scrutiny to distinguish topological from nontopological

O(1)

contributions. This is also the case for quantum systems, for which we discuss which entropies are sensitive to these connectivity contributions. We showcase these findings by extensive numerical simulations of a classical variant of the toric code model, for which we study the stability of topological order in the presence of a magnetic field and at finite temperatures from a R\'enyi entropy perspective.