Physics (Internal)

Interacting lattice systems with a model of quantum dissipation from a thermodynamic perspective

This event is part of the Biophysics/Condensed Matter Seminar Series.

Quantum dissipation arises when a large system can be split in a quantum system and an environment where the energy of the former flows to. We propose a conceptually simple approach to introduce the dissipation into interacting quantum systems (the XXZ model) in a thermodynamical context, in which every site of the 1d lattice is coupled to its own bath. In case of Ohmic diagonal coupling, a bath-induced Bose liquid phase can occur in the ground state phase diagram away from half filling. This phase is compressible, gapless, and conducting but not superfluid. At haf-filling, only a Luttinger liquid and a density wave ordered phase are found. The phase transition between them is of Kosterlitz-Thouless type where the Luttinger parameter takes a non-universal value. In case of off-diagonal coupling, we find a compressible zero-temperature state with spontaneous discrete symmetry breaking and a thermal phase transition for a one-dimensional system. Our results are supported by Quantum Monte Carlo path integral simulations.