Wenjuan Yang

Ultrastrong-coupling quantum-phase-transition phenomena in a few-qubit circuit QED system

2017 · Physical Review A

We study ultrastrong-coupling quantum-phase-transition phenomena in a few-qubit system. In the one-qubit case, three second-order transitions occur and the Goldstone mode emerges under the condition of ultrastrong-coupling strength. Moreover, a first-order phase transition occurs between …