Abstract
A theoretical framework to investigate the time evolution of the quantum entanglement due to the dynamical Lamb effect between two and three superconducting qubits coupled to a coplanar waveguide in the presence of different sources of dissipation is developed. Guidelines on how to proceed in the -qubit case are also given. We quantitatively analyze the case of single switching of the coupling and absence of dissipation within a perturbative approach and show that it is a good approximation to the case of periodic switching of the coupling for high frequencies of switching. The same systems are analyzed for the general case of periodic switching of the coupling at any frequency and in the presence of dissipation via numerical calculations. Different measures of entanglement compatible with mixed states are adopted. It is demonstrated that the different measures show a different level of detail of the latter. The concurrence and the negativity are obtained in the two-qubit case; the three- and the negativity are obtained in the three-qubit case. It is shown that time-dependent Greenberger-Horne-Zeilinger states can be created even in the presence of dissipation. To maximize the quantum entanglement between the qubits, the effects of tuning several parameters of the system are investigated.
- Received 20 June 2018
DOI:https://doi.org/10.1103/PhysRevA.98.042325
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