Universal control induced by noise
Universal control induced by noise
复制标题
噪声引起的通用控制
DOI：
10.1103/physreva.93.062308
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发表时间：
2016
影响因子：
2.9
通讯作者：
Arenz C
中科院分区：
文献类型：
--
作者：
Arenz C
在量子芝诺效应的基础上，最近已经证明了[D. K. Burgarth，Nat. Commun. 5，5173（2014）2041-172310.1038/ncomms 6173]，局部施加在量子系统的一部分上的强振幅阻尼过程可以对系统的其余部分的动力学具有有益的影响。没有耗散就不能实现的量子操作，通过强耗散过程的作用变得可以实现。在这里，我们概括了这个想法，确定退相干自由子空间（DFS）的子空间中的动力学变得更加复杂。应用量子控制理论的方法，我们描述了一组可达操作的DFS内。我们提供了三个例子，成为完全可控的DFS内，而在没有耗散的情况下，对原始希尔伯特空间的控制是微不足道的。特别是，我们表明，（经典）伊辛哈密顿变成海森堡哈密顿的强集体退相干，这提供了通用的量子计算内的DFS。此外，我们进行数字门优化，研究如何处理保真度的规模与噪声强度。作为一个副产品，子系统保真度，可应用于其他开放量子系统的优化问题。
On the basis of the quantum Zeno effect, it has been recently shown [D. K. Burgarth , Nat. Commun. 5, 5173 (2014)2041-172310.1038/ncomms6173] that a strong-amplitude-damping process applied locally on a part of a quantum system can have a beneficial effect on the dynamics of the remaining part of the system. Quantum operations that cannot be implemented without the dissipation become achievable by the action of the strong dissipative process. Here we generalize this idea by identifying decoherence-free subspaces (DFSs) as the subspaces in which the dynamics becomes more complex. Applying methods from quantum control theory, we characterize the set of reachable operations within the DFSs. We provide three examples that become fully controllable within the DFSs while the control over the original Hilbert space in the absence of dissipation is trivial. In particular, we show that the (classical) Ising Hamiltonian is turned into a Heisenberg Hamiltonian by strong collective decoherence, which provides universal quantum computation within the DFSs. Moreover, we perform numerical gate optimization to study how the process fidelity scales with the noise strength. As a by-product, a subsystem fidelity that can be applied in other optimization problems for open quantum systems is developed.