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.

Keywords:

• quantum discord
• entanglement
• quantum dots
• cavity QED
• bistability
• dissipation

Acknowledgements

The authors wish to thank Dr S. Singh for many helpful discussions.