利用原子和光腔作用实现受控非门

摘要

First,we prepared two five-levelΛ-type atoms in ground states g 1 >and g 2 >.Next we let them pass through this double-mode (a mode and b mode)optical cavity.And a-mode couples with the transition g >→ e>,b-mode couples with the transition e>→ f >,with the coupling strength g a and g b respectively.We coded the information on the polarized photon states to measure the cavity polarization states after the atoms passed through the cavity. The C-NOT gate is realized by controlling the interaction time of atoms and intra-cavity fields.High fidelity and low photon loss can be realized by selecting reasonable parameters.The numerical results show that to realize C-NOT gate,the cavity with a strong coupling and little decay is necessary.When we set single-photon detuning Δ=0.5g ,and g/k is from 2 to 10,the fidelity can be keeping over 99%.%分别在2个基态g 1>和g 2>上制备2个相同的五能级Λ型原子，再将其通过一个双模( a模和b模)光腔，其中a模光子耦合下能级g>到中间能级e>的跃迁， b模光子耦合中间能级e>到上能级f>的跃迁，耦合强度分别为g a和g b .将信息编码在腔模的偏振光子态上，在原子通过光腔后测量腔的偏振光子态.数值计算结果表明：通过控制原子与内腔场的相互作用时间可实现受控非门；当单光子失谐Δ=0.5 g ， g/k=2~10时，保真度均大于99%.