Abstract

Strong many-body correlations in the quantum regime are often underlined by a quantum phase transition. The question whether such a transition may survive coupling to an external dissipative environment is evidently of fundamental importance. Decades ago it has been shown that for systems characterized by a discrete symmetry, varying the strength of dissipative coupling may induce a quantum phase transition. In our work we have focused on a similar question in the context of a system possessing a continuous symmetry. Specifically, we have addressed the physics of metallic quantum dots, that may or may not possess magnetic moments. We have shown that as a quantum dot is embedded more strongly in a dissipative environment, transition from a mesoscopic Stoner magnetic phase to a non-magnetic phase takes place. The quantum phase transition is the result of dissipative suppression of a phenomenon known in high energy as Coleman-Weinberg mechanism of continuous symmetry breaking.

Talk is based on I. S. Burmistrov, Y. Gefen, D. S. Shapiro, A. Shnirman, Phys. Rev. Lett. 124, 196801 (2020).