November 13 2013 Wednesday 15:30
Yusuf Gül, Boğaziçi University
Jahn-Teller systems in circuit QED

Abstract: We investigate the simulation of Jahn-Teller models with two nondegenerate vibrational modes using a circuit QED architecture. Typical Jahn-Teller systems are anisotropic and require at least a two-frequency description. The proposed simulator consists of two superconducting lumped-element resonators interacting with a common flux qubit in the ultrastrong coupling regime. An exact transformation between the two-frequency JT Hamiltonian and the circuit QED Hamiltonian has been established. The transformation permits describing the system in terms of an effective privileged single mode under certain conditions of the control parameters of the circuit QED system. The effective disadvantaged mode can be decoupled from the privileged one in the ultrastrong coupling regime. It is shown that the system can be systematically tuned to an effective single-mode Hamiltonian from the two-mode model by varying the coupling strength between the resonators. The tunability of the pure two-mode JT model and the effective privileged mode model is found to be feasible in the ultrastrong coupling circuit QED within the range of parameters in present experiments.