Lee Jae Weon, Shepelyansky Dima L
Laboratoire de Physique Théorique, UMR 5152 du CNRS, Université Paul Sabatier, 31062 Toulouse Cedex 4, France.
Phys Rev E Stat Nonlin Soft Matter Phys. 2005 May;71(5 Pt 2):056202. doi: 10.1103/PhysRevE.71.056202. Epub 2005 May 5.
Using the methods of quantum trajectories we investigate the effects of dissipative decoherence in a quantum computer algorithm simulating dynamics in various regimes of quantum chaos including dynamical localization, the quantum ergodic regime, and quasi-integrable motion. As an example we use the quantum sawtooth algorithm which can be implemented in a polynomial number of quantum gates. It is shown that the fidelity of quantum computation decays exponentially with time and that the decay rate is proportional to the number of qubits, number of quantum gates, and per gate dissipation rate induced by external decoherence. In the limit of strong dissipation the quantum algorithm generates a quantum attractor which may have a complex or simple structure. We also compare the effects of dissipative decoherence with the effects of static imperfections.
我们运用量子轨迹方法，研究了量子计算机算法中耗散退相干的影响，该算法模拟了量子混沌各种状态下的动力学，包括动力学局域化、量子遍历状态和准可积运动。作为示例，我们使用了可通过多项式数量的量子门实现的量子锯齿算法。结果表明，量子计算的保真度随时间呈指数衰减，且衰减率与量子比特数、量子门数量以及由外部退相干引起的每个门的耗散率成正比。在强耗散极限下，量子算法会产生一个可能具有复杂或简单结构的量子吸引子。我们还比较了耗散退相干的影响与静态缺陷的影响。
