腔QED中四能级系统的非传统几何量子位相门

Unconventional geometric quantum phase gates with four-level systems in cavity QED

我们提出在腔中的四能级系统中,通过非寻常几何相移,实现2比特量子位相门。在门操作过程中,原子没有跃迁,但是在位相空间中,腔模呈现环状分布,这个门操作依赖于原子态的几何位相。在特定的条件下,原子可以与腔模退纠缠,而且门对原子自发辐射和腔模衰变都不敏感。

We present a proposal for implementing two-qubit quantum phase gates through an unconventional geometric phase shift with 4-level systems in a cavity. The atoms undergo no transitions during the gate operation, while the cavity mode is displaced along a circle in the phase space, acquiring a geometric phase depending conditionally upon the atomic state. Under certain conditions, the atoms are disentangled with the cavity mode and thus the gate is insensitive to both the atomic spontaneous emission and the cavity decay .