Dynamics of thermalisation in small Hubbard-model systems

Abstract

We study numerically the thermalisation and temporal evolution of the reduced density matrix for a two-site subsystem of a fermionic Hubbard model prepared far from equilibrium at a definite energy. Even for very small systems near quantum degeneracy, the subsystem can reach a steady state resembling equilibrium. This occurs for a non-perturbative coupling between the subsystem and the rest of the lattice where relaxation to equilibrium is Gaussian in time, in sharp contrast to perturbative results. We find similar results for random couplings, suggesting such behaviour is generic for small systems.

4 pages, 5 figures

References in corpus (8)

• Thermalization and its mechanism for generic isolated quantum systems
• Single-Atom Resolved Fluorescence Imaging of an Atomic Mott Insulator
• Typicality for Generalized Microcanonical Ensembles
• Decoherence induced by interacting quantum spin baths
• Universal decoherence induced by an environmental quantum phase transition
• Decoherence by a spin thermal bath: Role of the spin-spin interactions and initial state of the bath
• Unitarity, ergodicity, and quantum thermodynamics
• Global and local relaxation of a spin-chain under exact Schroedinger and master-equation dynamics