"Light-cone" dynamics after quantum quenches in spin chains

Abstract

Signal propagation in the non equilibirum evolution after quantum quenches has recently attracted much experimental and theoretical interest. A key question arising in this context is what principles, and which of the properties of the quench, determine the characteristic propagation velocity. Here we investigate such issues for a class of quench protocols in one of the central paradigms of interacting many-particle quantum systems, the spin-1/2 Heisenberg XXZ chain. We consider quenches from a variety of initial thermal density matrices to the same final Hamiltonian using matrix product state methods. The spreading velocities are observed to vary substantially with the initial density matrix. However, we achieve a striking data collapse when the spreading velocity is considered to be a function of the excess energy. Using the fact that the XXZ chain is integrable, we present an explanation of the observed velocities in terms of "excitations" in an appropriately defined generalized Gibbs ensemble.

4+pages, 5 figures, supplementary material

References in corpus (18)

• Thermalization and its mechanism for generic isolated quantum systems
• Matrix Product Density Operators: Simulation of finite-T and dissipative systems
• Quantum Quench in the Transverse Field Ising Chain
• Lieb-Robinson bounds and the generation of correlations and topological quantum order
• Exact relaxation in a class of non-equilibrium quantum lattice systems
• Dephasing and the steady state in quantum many-particle systems
• Quenching the Anisotropic Heisenberg Chain: Exact Solution and Generalized Gibbs Ensemble Predictions
• Generalized Thermalization in an Integrable Lattice System
• Correlations after quantum quenches in the XXZ spin chain: Failure of the Generalized Gibbs Ensemble
• Spreading of correlations and entanglement after a quench in the one-dimensional Bose-Hubbard model
• Minimally Entangled Typical Thermal State Algorithms
• Quantum quench dynamics of the Luttinger model
• Quantum Quench in the Transverse Field Ising Chain II: Stationary State Properties
• Spectral functions in one-dimensional quantum systems at T>0
• Time evolution of correlations in strongly interacting fermions after a quantum quench
• Generalized TBA and generalized Gibbs
• Mean values of local operators in highly excited Bethe states
• Real-time dynamics at finite temperature by DMRG: A path-integral approach

Cited by in corpus (5)

• Eigenstate thermalization hypothesis (ETH) and integrability in quantum spin chains
• Stationary states in a free fermionic chain from the Quench Action Method
• Analytical expression for a post-quench time evolution of the one-body density matrix of one-dimensional hard-core bosons
• Propagation of a single hole defect in the one-dimensional Bose-Hubbard model
• Quantum Quench for inhomogeneous states in the non-local Luttinger model