Observation of the Sign Reversal of the Magnetic Correlation in a Driven-Dissipative Fermi Gas in Double Wells

Abstract

We report the observation of the sign reversal of the magnetic correlation from antiferromagnetic to ferromagnetic in a dissipative Fermi-Hubbard system, utilizing the dissipation caused by on-site two-body losses in a controlled manner. We systematically measure dynamics of the nearest-neighbor spin correlation in a double-well optical lattice, as well as a crossover of a double-well lattice to a one-dimensional uniform lattice. In a wide range of lattice configurations over a double-well lattice, we observe a ferromagnetic spin correlation, which is interpreted as a transient state leading to a Dicke state. This work demonstrates the control of quantum magnetism in open quantum systems with dissipation.

Dissipative Dynamics of a Fermionic Superfluid with Two-Body Losses

“…Surprisingly we show that dissipation not only damps out the synchronization dynamics, but also dramatically changes the coherent oscillations of the order parameter which become faster for increasing dissipation rate. Our results can be experimentally tested in experiments with ultracold fermionic superfluids [55,56], where two-body losses can be introduced through photoassociation [33,35].…”

“…Dissipative quantum many-body systems represent a fresh platform where novel dynamical phenomena and phase transition can appear as result of the competition between unitary evolution and dissipative couplings [24][25][26]. For bosonic or fermionic particles these can model both single particle processes such as pump and losses as well as correlated effects, such as heating due to stimulated emission [27][28][29], spontaneous emission [30] or twoparticle losses [31][32][33][34][35]. These types of dissipative inelastic scattering processes naturally arise for example in experiments with ultracold fermions made of Alkali-Earth atoms [36][37][38].…”