关键词: 量子点, 耦合腔, 量子纠缠, Negativity

Abstract: It studies a system of two coupled cavities, one containing a twolevel quantum dot and the other containing a threelevel tunneling quantum dot molecule. The state vector of the system was derived under the assumption of resonant interaction and the initial conditions that the quantum dot was in the excited state, the quantum dot molecule in the ground state, and the cavity fields were in a vacuum. The dotmolecule entanglement, cavitycavity entanglement, dotcavity entanglement and moleculecavity entanglement were discussed. The influence of coupling coefficeint between cavities and tunneling strength of the quantum molecule on entanglement properties was explored with Negativity used to measure the entanglement between subsystems. Numerical results show that, compared with the weak cavitycoupling case, strong cavity coupling makes the entanglement between the quantum dot (or the tunneling quantum dot molecule) and the corresponding cavity field, and that between the fields reduce, while entanglement between the quantum dot atom and the tunneling quantum dot molecule increases. On the other hand, for either weak or strong coupling between the cavities, with quantum dot molecule tunneling strength increasing, entanglement between the quantum dot (or molecule), and that between fields are slightly affected; only entanglement between the molecule and its cavity field is obviously reduced.

Key words: quantum dot, coupled cavities, quantum entanglement, Negativity