Controlling Speedup Induced by a Hierarchical Environment

• 作者: Jing Wang Wenyu Ji Yunan Wu
• 来源期刊: 现代物理(英文)
• 学科: 医学
• 关键词: Non-Markovianity QUANTUM SPEED LIMIT Time PHOTONIC Crystal
• 年，卷（期）: xdwlyw_2019,（10）
• 页码范围: 1177-1189
• 页数: 13页
• 分类号: R73

摘要

Quantum speedup of an open quantum system can be induced by the non-Markovian effect of the environment. Although an environment with a higher degree of non-Markovianity may seem like it should cause a faster speed of quantum evolution, this seemingly intuitive thinking may not always be correct. To clarify this point, we give a mechanism for controlling speedup of a single qubit that is coupled to a hierarchical photonic-crystal (PC) environment, which contains a defect single-mode cavity and a semi-infinite one-dimensional (1D) waveguide. Via studying the dynamics of the qubit, we reveal that with a judicious choice of the qubit-cavity coupling strength and the memory time of the waveguide environment, a speed-up evolution can be achieved. In particular, we found that the quantum speedup is not entirely attributed to the non-Markovianity, but to the increase of the total amount of flow information. That is the intrinsic physical reason that the hierarchical environment may induce the speed-up process. Our results may open new perspectives for detecting quantum speedup in realistic environments.