A geometric phase for superconducting qubits under the decoherence effect

Liyuan Xue, Yanxia Yu, Xiaoya Cai +2 more

G. R. Zeng, Yanyan Jiang, Z. Q. Chen +1 more

Gerd Schön, Alexander Shnirman, Pablo San-José +2 more

S. Abdel‐Khalek, K. Berrada, Mohamed A. El-Sayed +1 more

We propose a relaxation rate or dissipative cavity-based parameters that can be used as indicators of the stationary limit of a mixed state geometric phase. We perform our considerations for the system of a superconducting qubit in an open transmission line or interacting with a dissipative cavity. This system is very useful for performing an effective quantum computation by exhibiting the long collapse time of the geometric phase. It is shown that the geometric phase in the stationary limit does not depend on interaction time if the decay time exceeds an upper bound.

Wen‐Xing Yang, Ai-Xi Chen

In the system with superconducting quantum interference devices (SQUID) in cavity, a scheme for constructing two-qubit quantum phase gate via a conventional geometric phase-shift is proposed by using a quantized cavity field and classical microwave pulses. In this scheme, the gate operation is realized in the subspace spanned by the two lower flux states of the SQUID system and the population operator of the excited state has no effect on it. Thus the effect of decoherence caused from the levels of the SQUID system is possible to minimize. Under cavity decay, our strictly numerical simulation shows that it is also possible to realize the unconventional geometric phase gate. The experimental feasibility is discussed in detail.

Zhihui Peng, Songlin Li, Songlin Li +1 more