近日，美国哈佛大学Eric J. Heller团队研究了量子声学中的极化子突变。相关论文于2025年6月3日发表在《美国科学院院刊》杂志上。

量子声学框架最近作为一种非微扰、相干的电子-晶格相互作用方法出现，揭示了丰富的物理现象，这些现象往往被非相干散射事件的微扰方法所掩盖。

研究组在这个框架内模拟了电子和声晶格振动的强耦合动力学，将晶格振动表示为相干态，将电子表示为量子波包，其方式与紧束缚或基于离散跳跃的方法截然不同。他们推导并数值实现了晶格上的电子反作用，为电子波包演化和声极化子的形成提供了直观和定量的见解。 

研究组分析了不同材料参数下的极化子结合能，并计算了随时间变化的关键可观测值，包括均方位移、动能、势能和振动能。该发现揭示了有利于极化子形成的条件，低温、高变形势常数、慢声速和高效质量会增强极化子的形成。此外，研究组还探索了外部电场和磁场的影响，结果表明，虽然极化子的形成在中等电场下保持稳定，但在较高场强下受到微弱抑制。这些结果加深了人们对极化子动力学的理解，并为未来研究量子材料中的非平凡输运行为铺平了道路。

附：英文原文

Title: Polaron catastrophe within quantum acoustics

Author: Aydin, Alhun, Keski-Rahkonen, Joonas, Graf, Anton M., Yuan, Shaobing, Ouyang, Xiao-Yu, Müstecaplolu, zgür E., Heller, Eric J.

Issue&Volume: 2025-6-3

Abstract: The quantum acoustic framework has recently emerged as a nonperturbative, coherent approach to electron–lattice interactions, uncovering rich physics often obscured by perturbative methods with incoherent scattering events. Here, we model the strongly coupled dynamics of electrons and acoustic lattice vibrations within this framework, representing lattice vibrations as coherent states and electrons as quantum wave packets, in a manner distinctively different from tight-binding or discrete hopping-based approaches. We derive and numerically implement electron backaction on the lattice, providing both visual and quantitative insights into electron wave packet evolution and the formation of acoustic polarons. We investigate polaron binding energies across varying material parameters and compute key observables—including mean square displacement, kinetic energy, potential energy, and vibrational energy—over time. Our findings reveal the conditions that favor polaron formation, which is enhanced by low temperatures, high deformation potential constants, slow sound velocities, and high effective masses. Additionally, we explore the impact of external electric and magnetic fields, showing that while polaron formation remains robust under moderate fields, it is weakly suppressed at higher field strengths. These results deepen our understanding of polaron dynamics and pave the way for future studies into nontrivial transport behavior in quantum materials.

DOI: 10.1073/pnas.2426518122

Source: https://www.pnas.org/doi/abs/10.1073/pnas.2426518122