Universal time-fluctuations in near-critical out-of-equilibrium quantum dynamics

Abstract

Out of equilibrium quantum systems, on top of quantum fluctuations, display complex temporal patterns. Such time fluctuations are generically exponentially small in the system volume and can be therefore safely ignored in most of the cases. However, if one consider small quench experiments, time fluctuations can be greatly enhanced. We show that time fluctuations may become stronger than other forms of equilibrium quantum fluctuations if the quench is performed close to a critical point. For sufficiently relevant operators the full distribution function of dynamically evolving observable expectation values, becomes a universal function uniquely characterized by the critical exponents and the boundary conditions. At regular points of the phase diagram and for non sufficiently relevant operators the distribution becomes Gaussian. Our predictions are confirmed by an explicit calculation on the quantum Ising model.

5+2 pages, 1 figure

References in corpus (16)

• Foundation of Statistical Mechanics under experimentally realistic conditions
• Quantum critical scaling of the geometric tensors
• Lieb-Robinson Bounds and the Exponential Clustering Theorem
• Generalized Thermalization in an Integrable Lattice System
• Dynamical Phase Transitions and Instabilities in Open Atomic Many-Body Systems
• Quantum Monte Carlo simulations of confined bosonic atoms in optical lattices
• Decoherence induced by interacting quantum spin baths
• Local quantum criticality in confined fermions on optical lattices
• Large deviations and universality in quantum quenches
• Quenches in a quasi-disordered integrable lattice system: Dynamics and statistical description of observables after relaxation
• Exact infinite-time statistics of the Loschmidt echo for a quantum quench
• Universal Rephasing Dynamics after a Quantum Quench via Sudden Coupling of Two Initially Independent Condensates
• Order parameter statistics in the critical quantum Ising chain
• Time Fluctuations in Isolated Quantum Systems of Interacting Particles
• Gaussian Equilibration
• Numerical simulations of strongly correlated fermions confined in 1D optical lattices

Cited by in corpus (8)

• Quantum many-body systems out of equilibrium
• Structure of eigenstates and quench dynamics at an excited state quantum phase transition
• Quantum quench dynamics in Dicke superradiance models
• Many-Body Dephasing in a Trapped-Ion Quantum Simulator
• Many-particle dephasing after a quench
• Dynamics and level statistics of interacting fermions in the Lowest Landau Level
• Equilibration on average in quantum processes with finite temporal resolution
• Small quench dynamics as a probe for trapped ultracold atoms