发表机构
Institute for Theoretical Physics, ETH Zürich; IBM Quantum, IBM Research – Zurich; Max-Planck-Institut für Quantenoptik; Munich Center for Quantum Science and Technology (MCQST); Fakultät für Physik, Ludwig-Maximilians-Universität（苏黎世联邦理工学院理论物理研究所; IBM量子，IBM苏黎世研究实验室; 马克斯·普朗克量子光学研究所; 慕尼黑量子科学与技术中心; 路德维希-马克西米利安大学物理学院）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文提出基于非线性光谱和涨落的协议，通过密度和电流响应及累积量区分强相关系统中的电子与空穴准粒子，并在费米-哈伯德梯子和硬核玻色子梯子中验证，为量子模拟器提供无需霍尔测量的载流子符号表征方法。
AI 中文摘要
传统上，表征强关联量子系统中的载流子类型依赖于霍尔效应。在冷原子量子模拟器中，实现霍尔输运测量通常需要合成规范场，这会引入显著的加热效应。在此，我们提出了基于非线性光谱和涨落的协议，为识别准粒子电荷符号提供了一条替代途径。我们证明了，对有限动量淬火和驱动的二阶密度和电流响应，以及平衡态下的三阶密度累积量，能够区分电子型与空穴型准粒子。对于方格上的费米-哈伯德多腿梯子，数值模拟揭示了从空穴型到电子型载流子的交叉，发生在远离半填充的空穴掺杂时，这与霍尔系数的符号变化一致。为了证明我们的协议在费米子系统之外的适用性，我们展示了在硬核玻色子梯子中，对有限动量、有限频率驱动的非线性密度响应揭示了载流子的电荷符号，并且当驱动接近非线性集体模的共振时，非线性信号可以显著增强。我们的结果确立了非线性密度和电流响应以及平衡态非高斯涨落作为互补探针，为量子模拟器提供了一条直接表征载流子符号的途径，避免了传统输运装置中的实验障碍。
英文摘要
Characterizing carrier type in strongly correlated quantum systems conventionally relies on the Hall effect. In cold-atom quantum simulators, implementing Hall transport measurements typically requires synthetic gauge fields, which introduces significant heating. Here, we present nonlinear spectroscopic and fluctuation-based protocols that establish an alternative route to identifying the sign of quasiparticle charge. We demonstrate that second-order density and current responses to finite-momentum quenches and drives-as well as equilibrium third-order density cumulants-distinguish electron- from hole-like quasiparticles. For a Fermi-Hubbard multi-leg ladder on a square lattice, numerical simulations reveal a crossover from hole- to electron-like carriers upon hole-doping away from half-filling, matching the sign change in the Hall coefficient. To demonstrate the applicability of our protocols beyond fermionic systems, we show that the nonlinear density response to a finite-momentum, finite-frequency drive reveals the sign of charge carriers in a hard-core boson ladder, and that the nonlinear signal can be significantly enhanced when driving near resonance with a nonlinear collective mode. Our results establish nonlinear density and current response and equilibrium non-Gaussian fluctuations as complementary probes, offering quantum simulators a direct route to characterize the carrier sign, without the experimental hurdles of conventional transport setups.
Comments30 pages, 16 figures
