Andrey Moskalenko: Qubit Entanglement Generated by Classical Light Driving an Optical Cavity

Описание: Title: Qubit Entanglement Generated by Classical Light Driving an Optical Cavity
Abstract: We study the generation of entanglement between two qubits which communicate through a single cavity mode of quantum light but have no direct interaction. We show that such entanglement can be generated simply by exchanging quanta with a third party, which is in our case the cavity mode [1]. Exchanging only a single quantum creates maximal entanglement. A single quantum can be provided by an external quantum light source. However, we use a classical light source to pump quanta which are used for the exchange, and investigate the degree of two-qubit entanglement. We first identify a characteristic timescale of the interaction between the cavity mode and each qubit. We investigate a regime where the driving pulse length short compared to the characteristic timescale of the interaction. In this regime, it is known that the pulse can pump the system by generating a displacement of the cavity mode. This is a classical response which can be obtained by a corresponding set of Hamilton equations. We show that, by using a specific pulse shape, one can make the displacement to essentially vanish after the pulse finishes interaction with the cavity mode. In this case, a rotation of the qubits can be invoked as a quantum response, resulting from a nonvanishing commutator between the free and the interaction Hamiltonian.

[1] S. Ahn, A. S. Moskalenko, V. Y. Chernyak, and S. Mukamel, arXiv:2306.10436.