Long-range correlations and ensemble inequivalence in a generalized ABC model

A generalization of the ABC model, a one-dimensional model of a driven system of three particle species with local dynamics, is introduced, in which the model evolves under either (i) density-conserving or (ii) nonconserving dynamics. For equal average densities of the three species, both dynamical models are demonstrated to exhibit detailed balance with respect to a Hamiltonian with long-range interactions. The model is found to exhibit two distinct phase diagrams, corresponding to the canonical (density-conserving) and grand canonical (density nonconserving) ensembles, as expected in long-range interacting systems. The implication of this result to nonequilibrium steady states, such as those of the ABC model with unequal average densities, are briefly discussed.Comment: 4 pages, 2 figures. v2: minor changes with an added reference, published versio

Comment on Quantum Interference between Light Sources Separated by 150 Million Kilometers Deng et al. PHYSICAL REVIEW LETTERS 123, 080401 (2019)

This is a comment on the paper : Quantum Interference between Light Sources Separated by 150 Million Kilometers by Deng et al, PHYSICAL REVIEW LETTERS 123, 080401 (2019

Probing anomalous relaxation by coherent multidimensional optical spectroscopy

We propose to study the origin of algebraic decay of two-point correlation functions observed in glasses, proteins, and quantum dots by their nonlinear response to sequences of ultrafast laser pulses. Power-law spectral singularities and temporal relaxation in two-dimensional correlation spectroscopy (2DCS) signals are predicted for a continuous time random walk model of stochastic spectral jumps in a two level system with a power-law distribution of waiting times $\psi (t)\sim t^{-\alpha -1}$. Spectroscopic signatures of stationary ensembles for $1<\alpha <2$ and aging effects in nonstationary ensembles with $0<\alpha <1$ are identified

Quantum Extension of the Jarzynski Relation

The relation between the distribution of work performed on a classical system by an external force switched on an arbitrary timescale, and the corresponding equilibrium free energy difference, is generalized to quantum systems. Using the adiabatic representation we show that this relation holds for isolated systems as well as for systems coupled to a bath described by a master equation. A close formal analogy is established between the present classical trajectory picture over populations of adiabatic states and phase fluctuations (dephasing) of a quantum coherence in spectral lineshapes, described by the stochastic Liouville equation