Coherence properties of discrete static kinks

Kink correlations, domain size distribution, and the emptiness formation probability after the Kibble-Zurek quench in the quantum Ising chain

Linear quench of the transverse field drives the quantum Ising chain across a quantum critical point from the paramagnetic to the ferromagnetic phase. We focus on normal and anomalous quadratic correlators between fermionic kink creation and annihilation operators. They depend not only on the Kibble-Zurek (KZ) correlation length but also on a dephasing length scale, which differs from the KZ length by a logarithmic correction. Additional slowing down of the ramp in the ferromagnetic phase further increases the dephasing length and suppresses the anomalous correlator. The quadratic correlators …

在囚禁离子量子模拟器中观测拓扑缺陷的量子叠加

Observation of quantum superposition of topological defects in a trapped ion quantum simulator

本文在囚禁离子量子模拟器中通过设计长程自旋相互作用，首次实验观测到拓扑缺陷的量子叠加，验证了“薛定谔扭结”的非局域性与量子相干性，为量子Kibble-Zurek非平衡动力学研究提供了新工具。

Dynamics of topological defects in ion Coulomb crystals

We study experimentally and theoretically the properties of structural defects (kink solitons) in two-dimensional ion Coulomb crystals. We show how different types of kink solitons with different physical properties can be realized, and transformed from one type into another by varying the aspect ratio of the trap confinement. Further, we discuss how impurities in ion Coulomb crystals, such as mass defects, can modify the dynamics of kink creation and their stability. For both pure and impure crystals, the experimentally observed kink dynamics are analyzed in detail and explained theoretically…

Protecting quantum coherences from static noise and disorder

Quantum coherences are paramount resources for applications, such as quantum-enhanced light-harvesting or quantum computing, which are fragile against environmental noise. We here derive generalized quantum master equations using perturbation theory in order to describe the effective ensemble-averaged time-evolution of finite-size quantum systems subject to static noise on all time scales. We then analyse the time-evolution of the coherences under energy broadening noise in a variety of systems characterized by both short and long-range interactions, by strongly correlated and fully uncorrelat…

Coherence of a driven electron spin qubit actively decoupled from quasi-static noise

The coherence of electron spin qubits in semiconductor quantum dots suffers mostly from low-frequency noise. During the last decade, efforts have been devoted to mitigate such noise by material engineering, leading to substantial enhancement of the spin dephasing time for an idling qubit. However, the role of the environmental noise during spin manipulation, which determines the control fidelity, is less understood. We demonstrate an electron spin qubit whose coherence in the driven evolution is limited by high-frequency charge noise rather than the quasi-static noise inherent to any semicondu…

静网络中不同拓扑结构的耗散量子动力学

Dissipative Quantum Dynamics in Static Network with Different Topologies

研究通过量子自旋模型与热浴耦合，探讨不同网络拓扑结构对量子耗散动力学的影响，并提出平均场方法扩展网络规模，揭示网络拓扑与量子相干性的关系。

Can Natural Sunlight Induce Coherent Exciton Dynamics?

Excitation of a model photosynthetic molecular aggregate by incoherent sunlight is systematically examined. For a closed system, the excited state coherence induced by the sunlight oscillates with an average amplitude that is inversely proportional to the excitonic gap, and reaches a stationary amplitude that depends on the temperature and coherence time of the radiation field. For an open system, the light-induced dynamical coherence relaxes to a static coherence determined by the non-canonical thermal distribution resulting from the entanglement with the phonon bath. The decay of the excited…

量子性与一对静态Unruh-DeWitt探测器的熵不确定性

Quantumness and entropic uncertainty for a pair of static Unruh-DeWitt detectors

本研究探讨了静态Unruh-DeWitt探测器中量子性与熵不确定性的关系，分析了能量比和距离对量子资源的影响。