一维量子接触过程中基于纠缠的临界性

中文摘要 AI 辅助

接触过程是非平衡动力学的范式示例，具有从化学到社会学的广泛应用。其量子对应物量子接触过程（QCP）将经典模型扩展至包含相干过程。尽管已有持续研究，但一维（1D）QCP的相变本质仍存在争议。本文结合Liouvillian谱分析、张量跳跃法、精确量子跳跃蒙特卡洛及截断维格纳模拟，表明1D QCP经历连续吸收态相变，其临界指数与经典情况不同。进一步发现，Liouvillian隙远低于临界点闭合，单独的谱隙分析无法区分QCP中的相变与亚稳态。关键的是，1D QCP是弱纠缠的，但这种弱纠缠对捕捉正确的临界行为不可或缺，而半经典方法会人为稳定活性态并预测虚假的一阶相变。本研究确立了1D QCP相变的量子起源，强调了纠缠在耗散量子多体系统中的关键作用。

英文摘要

The contact process is a paradigmatic example of nonequilibrium dynamics, with broad applications ranging from chemistry to sociology. Its quantum counterpart, the quantum contact process (QCP), extends the classical model to include coherent processes. Despite sustained interest, the nature of the transition in the one-dimensional (1D) QCP remains debatable. Here, combining Liouvillian spectral analysis, the tensor jump method, exact quantum jump Monte Carlo, and truncated Wigner simulations, we show that 1D QCP undergoes a continuous absorbing-state phase transition, with critical exponents distinct from the classical case. We further find Liouvillian gap closes well below the critical point, highlighting that spectral gap analysis alone cannot distinguish a phase transition from metastability in the QCP. Crucially, the 1D QCP is weakly entangled, yet even this weak entanglement is indispensable for capturing the correct critical behavior, whereas semiclassical methods artificially stabilize the active state and predict a spurious first-order transition. Our work establishes the quantum origin of the phase transition in the 1D QCP and underscores the essential role of entanglement in dissipative quantum many-body systems.

发表机构

• National Laboratory of Solid State Microstructures and School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University（南京大学固体微结构物理国家重点实验室和物理学院，先进微结构协同创新中心）
• School of Physics and Astronomy, and Centre for the Mathematics and Theoretical Physics of Quantum nonequilibrium Systems, University of Nottingham（诺丁汉大学物理与天文学院及量子非平衡系统数学与理论物理中心）
• Hefei National Laboratory（合肥国家实验室）

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