Qubit Entanglement Generated by Classical Light Driving an Optical Cavity

Explore the generation of entanglement between two qubits communicating through a single cavity mode of quantum light without direct interaction. Delve into the process of creating entanglement by exchanging quanta with a cavity mode, focusing on how maximal entanglement can be achieved with a single quantum exchange. Examine the use of a classical light source to pump quanta for exchange and investigate the resulting degree of two-qubit entanglement. Identify the characteristic timescale of interaction between the cavity mode and each qubit, and analyze the regime where the driving pulse length is short compared to this timescale. Learn how a specific pulse shape can make the cavity mode displacement essentially vanish after interaction, leading to a quantum response in the form of qubit rotation. Understand the implications of the nonvanishing commutator between the free and interaction Hamiltonian in this process.