Reentrant phase behavior in systems with density-induced tunneling

TL;DR

This paper investigates how strongly interacting many-body quantum systems can internally induce decoherence and phase transitions, revealing conditions for superfluid revival and the importance of proper coupling interpretation.

Contribution

It introduces a model showing internal density-induced tunneling effects causing decoherence and superfluid revival in a 2D bosonic system, highlighting the role of interactions and coupling assumptions.

Findings

Quantum decoherence can be generated internally without external dissipation.

Superfluid phase can revive at high interaction strengths.

Breakdown of superfluidity is naturally enforced by system cutoff.

Abstract

Open many body quantum systems play a paramount role in various branches of physics, such as quantum information, nonlinear optics or condensed matter. The dissipative character of open systems has gained a lot of interest especially within the fields of quantum optics, due to unprecedented stabilization of quantum coherence, and quantum information, with its desire to control environmental degrees of freedom. We look beyond the typical mechanism of dissipation associated with an external source and show that strongly interacting many particle systems can create quantum decoherence within themselves. We study a quantum bosonic two-dimensional many body system with extended interactions between particles. Analytical calculations show that the system can be driven out of its coherent state, which is prevalent among commonly used setups. However, we also observe a revival of the superfluid phase within the same framework for sufficiently large interaction strength. The breakdown of quantum coherence is inevitable, but can be misinterpreted if one assumes improper coupling between the constituents of the many particle system. We show an adequate path to retrieve physically relevant results and consider its limitations. The system displays a natural cutoff that enforces the breakdown of superfluidity.