Dresden 2017 – wissenschaftliches Programm
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DY: Fachverband Dynamik und Statistische Physik
DY 42: Coherent Quantum Dynamics (joint session DY/TT)
DY 42.6: Vortrag
Donnerstag, 23. März 2017, 11:00–11:15, ZEU 160
Transport in Out-of-Equilibrium XXZ Chains: Exact Profiles of Charges and Currents — •Bruno Bertini1, Mario Collura1,2, Jacopo De Nardis3, and Maurizio Fagotti3 — 1SISSA and INFN, Trieste, Italy — 2Oxford University, Oxford, United Kingdom — 3École normale supérieure, Paris, France
We consider the non-equilibrium time evolution of piecewise homogeneous states in the XXZ spin-1/2 chain, a paradigmatic example of an interacting integrable model. The initial state can be thought as the result of joining chains with different global properties. Through dephasing, at late times the state becomes locally equivalent to a stationary state which explicitly depends on position and time. We propose a kinetic theory of elementary excitations and derive a continuity equation which fully characterizes the thermodynamics of the model. We restrict ourselves to the gapless phase and consider cases where the chains are prepared: 1) at different temperatures; 2) in the ground state of two different models; 3) in the "domain wall" state. We find excellent agreement (any discrepancy is within the numerical error) between theoretical predictions and numerical simulations of time evolution based on TEBD algorithms. As a corollary, we unveil an exact expression for the expectation values of the charge currents in a generic stationary state.