Berlin 2015 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 19: Correlated Electrons: Nonequilibrium Quantum Many-Body Systems 2 (jointly with DY)

TT 19.1: Vortrag

Montag, 16. März 2015, 15:00–15:15, H 3010

Quenching the Anisotropic Heisenberg Chain: Exact Solution and Generalized Gibbs Ensemble Predictions — •Bram Wouters¹, Jacopo De Nardis¹, Michael Brockmann¹, Davide Fioretto^1,2, Marcos Rigol³, Rogier Vlijm¹, and Jean-Sébastien Caux¹ — ¹Institute for Theoretical Physics, University of Amsterdam, Science Park 904, Postbus 94485, 1090 GL Amsterdam, Netherlands — ²Institute for Theoretical Physics, Georg-August-Universität Göttingen, Friedrich-Hund-Platz 1, D-37077 Göttingen, Germany — ³Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, USA

We study quantum quenches in integrable spin 1/2 chains in which we evolve the ground state of the antiferromagnetic Ising model (i.e. the zero momentum Néel state) with the anisotropic Heisenberg Hamiltonian (with anisotropy Δ ≥1). For this nontrivially interacting situation, an application of the first-principles-based quench-action method allows us to give an exact description of the postquench steady state in the thermodynamic limit.We show that a generalized Gibbs ensemble, implemented using all known local conserved charges, fails to reproduce the exact quench-action steady state and to correctly predict postquench equilibrium expectation values of physical observables. This is supported by numerical linked-cluster calculations within the diagonal ensemble in the thermodynamic limit.