Persistent entanglement of valley exciton qubits in transition metal dichalcogenides integrated into a bimodal optical cavity

Abstract

We report dissipative dynamics of two valley excitons residing in the $K$ and $K^{\prime }$-valleys of bare WSe${}_2$ monolayer and the one being integrated into a bimodal optical cavity. In the former, only when the exciton-field detunings in the $K$ and $K^{\prime }$-valleys are rigorously equal (resonant detuning), partially entangled stationary states can be created. Otherwise the concurrence of exciton qubits turns to zero. Remarkably, in the latter (the WSe${}_2$ monolayer in a bimodal optical cavity), the transfers of entanglement from one subsystem (exciton/light) to the other (light/exciton) take place. Hence a finite stationary concurrence of exciton qubits is always generated, independent of whether the exciton-field detuning in two valleys is resonant or non-resonant. In addition, it can even reach as high as 1 (maximally entangled state of two valley excitons). Since there no real system which has a strictly resonant detuning, an immersion of the WSe${}_2$ monolayer in a bimodal optical cavity provides an opportunity to overcome the challenge facing by the bare WSe${}_2$, opening a novel realm of potential qubits.

13 pages, 10 figures, Supplemental Materials (4 pages)