Zagoskin A M, Ashhab S, Johansson J R, Nori Franco
Frontier Research System, The Institute of Physical and Chemical Research (RIKEN), Wako-shi, Saitama, Japan.
Phys Rev Lett. 2006 Aug 18;97(7):077001. doi: 10.1103/PhysRevLett.97.077001. Epub 2006 Aug 14.
The two-level systems (TLSs) naturally occurring in Josephson junctions constitute a major obstacle for the operation of superconducting phase qubits. Since these TLSs can possess remarkably long decoherence times, we show that such TLSs can themselves be used as qubits, allowing for a well controlled initialization, universal sets of quantum gates, and readout. Thus, a single current-biased Josephson junction can be considered as a multiqubit register. It can be coupled to other junctions to allow the application of quantum gates to an arbitrary pair of qubits in the system. Our results indicate an alternative way to realize superconducting quantum information processing.
约瑟夫森结中自然存在的两能级系统（TLSs）是超导相位量子比特运行的主要障碍。由于这些TLSs可能具有非常长的退相干时间，我们表明这样的TLSs自身可以用作量子比特，从而实现良好控制的初始化、通用量子门集以及读出。因此，单个电流偏置的约瑟夫森结可被视为一个多量子比特寄存器。它可以与其他结耦合，以便将量子门应用于系统中任意一对量子比特。我们的结果表明了一种实现超导量子信息处理的替代方法。
