Enhancement of discord and entanglement with detuning for two coupled quantum dots in a driven cavity

Abstract

We study the quantum discord for a system of two identical coupled quantum dots interacting with quantized cavity field in the presence of cavity as well as dot decay and detuning. The cavity is externally driven by a coherent light. These results are compared with the entanglement of the quantum dots in various parameter regimes in which system may or may not show bistability. We show that the discord in the steady state is nonzero for any nonzero cavity field amplitude. The system has higher discord in the upper branch of the bistability curve where the entanglement is zero. We also find many other interesting results including high discord and entanglement in the presence of detuning, a phenomenon which we further examine by approximating the density matrix in the appropriate limit.

Dynamics of super quantum discord and optimal dense coding in quantum channels

“…Recently, the cavity quantum electrodynamics system (CQES) has received much attention since this system offer an ideal coupling between atoms and photons [13]. As a result, it has been widely applied for engineering quantum entanglement and quantum channels [14][15][16][17][18][19][20]. Therefore, CQESs not only have been used to create entanglement, but also to display useful applications such as quantum state transfer.…”