【作者】 刘颖；

【导师】 苑震生；

【作者基本信息】 中国科学技术大学 ， 量子信息物理学， 2025， 博士

【摘要】 超冷原子光晶格系统因其高度并行的量子态调控能力、长相干寿命,及新近发展的单原子分辨探测与寻址技术,已逐渐成为量子模拟与量子信息处理领域的重要实验平台。本论文依托自主搭建的超冷原子光晶格实验平台,实现了单格点尺度上的高精度量子态操控与探测,围绕一维U(1)格点规范理论模型开展了系列量子模拟研究。首先,本论文系统介绍了自主搭建的超冷原子光晶格实验平台,包括超高真空环境、高稳定性激光系统和精密磁场控制等核心模块。特别地,论文中着重阐述了构成单格点分辨精度测控能力的关键实验技术,包括基于等臂干涉结构的超晶格、具备单原子与单格点分辨能力的量子气体显微镜,及运用数字微镜器件(DMD)实现的可编程光势场编辑技术。这套自主研发装置为后续的量子模拟研究奠定了实验基础。利用上述平台,我们首次实现了满足局域U(1)规范对称性约束的量子多体初态的确定性制备,并实时追踪了系统的动力学演化。通过绝热演化方法,我们研究了规范对称性约束下的量子相变行为,并首次在实验上确定了该模型的量子相变临界点。随后我们进一步探索了远离平衡条件下,同一初态构型的量子退火动力学过程,发现具有局域规范对称性的量子多体系统在临界点附近更易发生热化过程。这一结果揭示了格点规范场理论中非平衡态热化行为与量子临界性的内在关联。随后,我们进一步将线性倾斜势与超晶格势阱技术巧妙结合,成功实现了从玻色-哈伯德模型到背景电场可调U(1)量子链接模型的映射。这一映射关系的实现为后续模拟具有动态外场的量子电动力学(QED)模型奠定了基础。基于此,我们在实验中通过确定性地制备出粒子-反粒子对,并追踪了粒子对的动力学演化过程,首次展示了U(1)格点规范理论中禁闭相与解禁相的转变,为直观理解夸克禁闭机制提供了全新的微观图像。最后,基于上述背景电场可调U(1)量子链接模型模拟平台,我们进一步研究了格点施温格模型中的弦断裂现象。为此,我们提出并实现了一种基于绝热参数演化的方案,通过在演化过程中精确调控粒子静止质量与外电场弦张力参数,驱动系统绝热地穿越不同的量子相区域,并利用单格点分辨探测技术,详细刻画并分析了系统基态波函数在不同量子相区域的结构特征。首次在实验中揭示了弦断裂现象的微观机制,并确定了诱导弦断裂的共振条件。综上所述,本论文基于自主搭建的超冷原子光晶格系统,围绕格点规范理论中的量子相变、量子临界性与热化、禁闭动力学、伪真空衰变与弦断裂等重要问题,开展了系统性量子模拟实验研究工作,推动了对于高能物理中非微扰现象的理解,也为研究凝聚态物理中强关联量子多体系统提供了新的实验视角。更多还原

【Abstract】 The ultracold atomic optical lattice system has emerged as a significant experi-mental platform for quantum simulation and quantum information processing due to its highly parallel quantum state control capabilities,long coherence time,and the re-cently developed single-atom-resolved detection and addressing techniques.This the-sis,based on a self-developed ultracold atomic optical lattice experimental platform,achieves high-precision quantum state manipulation and detection at the single-site scale and conducts a series of quantum simulation studies on the one-dimensional U(1)lattice gauge theory model.First,this thesis systematically introduces the ultracold atomic optical lattice experimental platform constructed in-house,including key components such as the ultra-high vacuum environment,high-stability laser system,and precise magnetic field control.In particular,it emphasizes the critical experimental techniques that enable single-site-resolved measurement and control,including superlattice based on equal-arm interferometers,a quantum gas microscope capable of single-atom and single-site resolution,and programmable optical potential engineering using a dig-ital micromirror device(DMD).This self-developed apparatus lays the experimental foundation for subsequent quantum simulation studies.Using this platform,we have,for the first time,deterministically prepared quan-tum many-body initial states constrained by local U(1)gauge symmetry and tracked the system’s real-time dynamical evolution.By employing adiabatic evolution meth-ods,we studied quantum phase transition under gauge symmetry constraints and ex-perimentally determined the critical point of this model for the first time.Further-more,we explored quantum quench dynamics of the same initial state configuration far from equilibrium,revealing that quantum many-body systems with local gauge symmetry tend to thermalize more easily near critical points.This result uncovers an intrinsic connection between non-equilibrium thermalization behavior and quantum criticality in lattice gauge field theories.Subsequently,by ingeniously combining a linear tilt potential with superlat-tice potential techniques,we successfully mapped the Bose-Hubbard model onto a tunable-background-field U(1)quantum link model,laying the groundwork for simu-lating quantum electrodynamics(QED)models with dynamical external fields.Based on this,we deterministically prepared particle-antiparticle pairs in experiments and tracked their dynamical evolution,demonstrating the transition between the confined and deconfined phases in U(1)lattice gauge theory for the first time.This provides a novel microscopic picture for understanding quark confinement mechanisms.Finally,based on the aforementioned platform for simulating U(1)quantum link model with a tunable background electric field,we further investigated the string breaking phenomenon in the lattice Schwinger model.We proposed and implemented an adiabatic parameter evolution scheme,in which the system was driven adiabati-cally across different quantum phase regions by precisely tuning the rest mass of par-ticles and external electric field string tension during the evolution.By leveraging single-site-resolved detection techniques,we systematically characterized and ana-lyzed the structure of the system’s ground-state wavefunction in different quantum phases.We revealed the microscopic mechanism of string breaking and determined the resonance conditions that induce this phenomenon for the first time in the exper-iment.In summary,this thesis systematically conducts quantum simulation experiments based on a self-developed ultracold atomic optical lattice system,focusing on key issues in lattice gauge theories such as quantum phase transitions,quantum critical-ity and thermalization,confinement dynamics,and string breaking.This work ad-vances the understanding of non-perturbative phenomena in high-energy physics and provides a novel experimental perspective for studying strongly correlated quantum many-body systems in condensed matter physics.更多还原