Yuan Hao, Han Lian-Fang
Opt Express. 2016 Mar 7;24(5):5487-5501. doi: 10.1364/OE.24.005487.
We present an efficient proposal to realize quantum nondestructive determination (QNDD) of unknown single-qubit states in two types of low-Q cavities, i.e., single-sided and double-sided cavity QED systems. In the dispersive regime, we demonstrate that the QNDD of single-qubit states can be realized by detecting qubit-state-dependent phase shifts (QSDPSs) of the reflected or transmitted photons from the cavity in the single-photon input-output process. Our proposal could be straightforwardly extended to the case of multiple-qubit states. Furthermore, the experimental feasibility of our proposal is also analyzed in experimentally-demonstrated circuit QED systems. The distinct feature of our proposal is that our proposal works in the dispersive regime of low-Q cavities and it is robust to both cavity decay and atomic spontaneous emission.
我们提出了一种有效的方案，用于在两种低品质因数（Q）腔中实现对未知单量子比特态的量子无损测定（QNDD），即单边和双边腔量子电动力学（QED）系统。在色散区域，我们证明了在单光子输入-输出过程中，通过检测从腔反射或透射光子的与量子比特态相关的相移（QSDPSs），可以实现单量子比特态的QNDD。我们的方案可以直接扩展到多量子比特态的情况。此外，我们还在已通过实验验证的电路QED系统中分析了该方案的实验可行性。我们方案的独特之处在于它在低Q腔的色散区域工作，并且对腔衰减和原子自发辐射都具有鲁棒性。
