Monitoring entanglement evolution and collective quantum dynamics
Georg M. Reuther, David Zueco, Peter Hänggi, Sigmund Kohler · Physical Review B · 2011
We generalize a recently developed scheme for monitoring coherent quantum dynamics with good time resolution and low backaction [Reuther et al., Phys. Rev. Lett. 102, 033602 (2009)] to the case of more complex quantum dynamics of one or several qubits. The underlying idea is to measure with lock-in techniques the response of the quantum system to a high-frequency ac field. We demonstrate that this scheme also allows one to observe quantum dynamics with many frequency scales, such as that of a qubit undergoing Landau-Zener transitions. Moreover, we propose how to measure the entanglement between two qubits as well as the collective dynamics of qubit arrays.