Zhu Xiaobo, Matsuzaki Yuichiro, Amsüss Robert, Kakuyanagi Kosuke, Shimo-Oka Takaaki, Mizuochi Norikazu, Nemoto Kae, Semba Kouichi, Munro William J, Saito Shiro
1] NTT Basic Research Laboratories, NTT Corporation, 3-1 Morinosato-Wakamiya, Atsugi, Kanagawa 243-0198, Japan [2].
NTT Basic Research Laboratories, NTT Corporation, 3-1 Morinosato-Wakamiya, Atsugi, Kanagawa 243-0198, Japan.
Nat Commun. 2014 Apr 8;5:3424. doi: 10.1038/ncomms4524.
The hybridization of distinct quantum systems has opened new avenues to exploit the best properties of these individual systems. Superconducting circuits and electron spin ensembles are one such example. Strong coupling and the coherent transfer and storage of quantum information has been achieved with nitrogen vacancy centres in diamond. Recently, we have observed a remarkably sharp resonance (~1 MHz) at 2.878 GHz in the spectrum of flux qubit negatively charged nitrogen vacancy diamond hybrid quantum system under zero external magnetic field. This width is much narrower than that of both the flux qubit and spin ensemble. Here we show that this resonance is evidence of a collective dark state in the ensemble, which is coherently driven by the superposition of clockwise and counter-clockwise macroscopic persistent supercurrents flowing in the flux qubit. The collective dark state is a unique physical system and could provide a long-lived quantum memory.
不同量子系统的杂交开辟了新途径，以利用这些单个系统的最佳特性。超导电路和电子自旋系综就是这样一个例子。利用金刚石中的氮空位中心已经实现了强耦合以及量子信息的相干转移和存储。最近，我们在零外部磁场下的磁通量子比特带负电氮空位金刚石混合量子系统的光谱中，于2.878 GHz处观测到了一个非常尖锐的共振（~1 MHz）。这个宽度比磁通量子比特和自旋系综的宽度都要窄得多。在这里我们表明，这个共振是系综中集体暗态的证据，它由在磁通量子比特中顺时针和逆时针宏观持续超电流的叠加相干驱动。集体暗态是一个独特的物理系统，并且可以提供一个长寿命的量子存储器。
