Dissipative stabilization of entangled qubit pairs in quantum arrays with a single localized dissipative channel

Abstract

We study the dissipative stabilization of entangled states in arrays of quantum systems. Specifically, we are interested in the states of qubits (spin-1/2) which may or may not interact with one or more cavities (bosonic modes). In all cases only one element, either a cavity or a qubit, is lossy and irreversibly coupled to a reservoir. When the lossy element is a cavity, we consider a squeezed reservoir and only interactions which conserve the number of cavity excitations. Instead, when the lossy element is a qubit, pure decay and a properly selected structure of XY-interactions are taken into account. We show that in all cases, in the steady state, many pairs of distant, non-directly interacting qubits, which cover the whole array, can get entangled in a stationary way, by means of the interplay of dissipation and local interactions.

Free fermions in the repeated interactions scheme

“…The pairs are made of one element belonging to the first chain and the other to the second. It has been shown that the field can be tuned such that the entanglement is perfectly replicated and gives rise to a scale-free set of two-particles Bell states, a so-called rainbow state [9][10][11][12][13][14][15][16][17][18][19][20] .…”

“…This has been successfully done for fewbody quantum setups such as for example two trapped-ion quantum bits (qubits) for which the engineered dissipation was able to produce and stabilize a Bell state [7]. For many-body systems, proposals have been made to stabilize Gaussian entangled states of noninteracting bosons [8], as well as to engineer entangled rainbow states in spin chains and Fermi systems [9][10][11][12][13][14][15][16][17][18][19][20].…”