Quantum gas microscopy of Kardar-Parisi-Zhang superdiffusion

作者：David Wei, Antonio Rubio-Abadal, Bingtian Ye, Francisco Machado, Jack Kemp, Kritsana Srakaew, Simon Hollerith, Jun Rui, Sarang Gopalakrishnan, Norman Y. Yao, Immanuel Bloch, Johannes Zeiher · 发表于：Science · 年份：2022 · DOI：10.1126/science.abk2397 · 被引用次数：239 · 研究领域：Quantum many-body systems、Physics of Superconductivity and Magnetism、Theoretical and Computational Physics

The Kardar-Parisi-Zhang (KPZ) universality class describes the coarse-grained behavior of a wealth of classical stochastic models. Surprisingly, KPZ universality was recently conjectured to also describe spin transport in the one-dimensional quantum Heisenberg model. We tested this conjecture by experimentally probing transport in a cold-atom quantum simulator via the relaxation of domain walls in spin chains of up to 50 spins. We found that domain-wall relaxation is indeed governed by the KPZ dynamical exponent z = 3/2 and that the occurrence of KPZ scaling requires both integrability and a nonabelian SU(2) symmetry. Finally, we leveraged the single-spin–sensitive detection enabled by the quantum gas microscope to measure an observable based on spin-transport statistics. Our results yield a clear signature of the nonlinearity that is a hallmark of KPZ universality.