Mortezapour Ali, Lo Franco Rosario
Department of Physics, University of Guilan, P. O. Box 41335-1914, Rasht, Iran.
Dipartimento di Energia, Ingegneria dell'Informazione e Modelli Matematici, Università di Palermo, Viale delle Scienze, Edificio 9, 90128, Palermo, Italy.
Sci Rep. 2018 Sep 24;8(1):14304. doi: 10.1038/s41598-018-32661-2.
Finding strategies to preserve quantum resources in open systems is nowadays a main requirement for reliable quantum-enhanced technologies. We address this issue by considering structured cavities embedding qubits driven by a control technique known as frequency modulation. We first study a single qubit in a lossy cavity to determine optimal modulation parameters and qubit-cavity coupling regime allowing a gain of four orders of magnitude concerning coherence lifetimes. We relate this behavior to the inhibition of the qubit effective decay rate rather than to stronger memory effects (non-Markovianity) of the system. We then exploit these findings in a system of noninteracting qubits embedded in separated cavities to gain basic information about scalability of the procedure. We show that the determined modulation parameters enable lifetimes of quantum resources, such as entanglement, discord and coherence, three orders of magnitude longer than their natural (uncontrolled) decay times. We discuss the feasibility of the system within the circuit-QED scenario, typically employed in the current quantum computer prototypes. These results provide new insights towards efficient experimental strategies against decoherence.
如今，寻找在开放系统中保存量子资源的策略是可靠的量子增强技术的主要要求。我们通过考虑嵌入量子比特的结构化腔来解决这个问题，该腔由一种称为频率调制的控制技术驱动。我们首先研究有损腔中的单个量子比特，以确定最佳调制参数和量子比特 - 腔耦合 regime，从而使相干寿命提高四个数量级。我们将这种行为与量子比特有效衰减率的抑制相关联，而不是与系统更强的记忆效应（非马尔可夫性）相关联。然后，我们在嵌入分离腔中的非相互作用量子比特系统中利用这些发现，以获取有关该过程可扩展性的基本信息。我们表明，所确定的调制参数使量子资源（如纠缠、量子失协和相干性）的寿命比其自然（不受控制）衰减时间长三个数量级。我们讨论了该系统在电路量子电动力学（circuit-QED）场景中的可行性，该场景通常用于当前的量子计算机原型中。这些结果为针对退相干的高效实验策略提供了新的见解。
