Critical heat current fluctuations in Curie-Weiss model in and out of equilibrium

Abstract

In some models of nonequilibrium phase transitions, fluctuations of the analyzed currents have been observed to diverge with system size. To assess whether this behavior is universal across phase transitions, we examined heat current fluctuations in the Curie-Weiss model, a paradigmatic model of the paramagnetic-ferromagnetic phase transition, coupled to two thermal baths. This model exhibits phase transitions driven by both the temperature and the magnetic field. We find that at the temperature-driven phase transition, the heat current noise consists of two contributions: the equilibrium part, which vanishes with system size, and the nonequilibrium part, which diverges with system size. For small temperature differences, this leads to nonmonotonic scaling of fluctuations with system size. In contrast, at the magnetic-field-driven phase transition, heat current fluctuations do not diverge when observed precisely at the phase transition point. Instead, out of equilibrium, the noise is enhanced at the magnetic field values away but close to the phase transition point, due to stochastic switching between two current values. The maximum value of noise increases exponentially with system size, while the position of this maximum shifts towards the phase transition point. Finally, on the methodological side, the paper demonstrates that current fluctuations in large systems can be effectively characterized by combining a path integral approach for macroscopic fluctuations together with an effective two-state model describing subextensive transitions between the two macroscopic states involved in the phase transition.

16 pages, 14 figures. Additional references added

References in corpus (21)

• The large deviation approach to statistical mechanics
• Motility-Induced Phase Separation
• Thermodynamic uncertainty relation for biomolecular processes
• Observation of a dissipative phase transition in a one-dimensional circuit QED lattice
• Counting Statistics of Non-Markovian Quantum Stochastic Processes
• Symmetry in Full Counting Statistics, Fluctuation Theorem, and Relations among Nonlinear Transport Coefficients in the Presence of a Magnetic Field
• Signatures of a dissipative phase transition in photon correlation measurements
• Criticality-Enhanced Quantum Sensing via Continuous Measurement
• Current fluctuations in open quantum systems: Bridging the gap between quantum continuous measurements and full counting statistics
• Superconducting proximity effect in interacting quantum dots revealed by shot noise
• Full counting statistics of transport through two-channel Coulomb blockade systems
• Macroscopic Stochastic Thermodynamics
• Finite-time dynamical phase transition in non-equilibrium relaxation
• Coulomb-interaction effects in full counting statistics of a quantum-dot Aharonov-Bohm interferometer
• Diverging current fluctuations in critical Kerr resonators
• Landau theory for finite-time dynamical phase transitions
• Current fluctuations in nonequilibrium discontinuous phase transitions
• Nonequilibrium fluctuations of chemical reaction networks at criticality: The Schlögl model as paradigmatic case
• Dynamical signatures of discontinuous phase transitions: How phase coexistence determines exponential versus power-law scaling
• Phase diagram and specific heat of a nonequilibrium Curie-Weiss model
• Random walks on modular chains: Detecting structure through statistics

Cited by in corpus (6)

• Nonequilibrium fluctuation-response relations for state-current correlations
• Nonequilibrium fluctuation-response relations for state observables
• Macroscopic fluctuation-response theory and its use for gene regulatory networks
• Nonanalytic Landau functionals shaping the finite-size scaling of fluctuations and response functions in and out of equilibrium
• Synchronization of thermodynamically consistent stochastic phase oscillators
• Anomalous current fluctuations and mobility-driven clustering