近日，英国牛津大学的Shinichi Sunami及其研究小组取得一项新进展。经过不懈努力，他们发现二维玻色气体中动态BKT跃迁的普适标度律
在这项研究中，研究人员报道了对二维玻色气体中Berezinskii-Kosterlitz-Thouless（BKT）跃迁上由超流体到正常相的猝灭引发的普适动力学的测量。研究人员通过将二维气体分割成两部分来降低密度，实现了在临界点处的猝灭。随后，使用物质波干涉探测技术测量了局部相位波动，以研究弛豫动力学。结果表明，相位相关函数和涡旋密度的时间演化均遵循普适的标度律。这一结论得到了经典场模拟的验证，并通过实时重整化群论得到了解释。
据悉，理解多体量子系统的非平衡动力学是统计物理学的一个基本问题。通过实验探索这些系统的普遍特性，可以解决这些基本问题。
附：英文原文
Title: Universal scaling of the dynamic BKT transition in quenched 2D Bose gases
Author: Shinichi Sunami, Vijay Pal Singh, David Garrick, Abel Beregi, Adam J. Barker, Kathrin Luksch, Elliot Bentine, Ludwig Mathey, Christopher J. Foot
Issue&Volume: 2023-10-27
Abstract: The understanding of nonequilibrium dynamics in many-body quantum systems is a fundamental issue in statistical physics. Experiments that probe universal properties of these systems can address such foundational questions. In this study, we report the measurement of universal dynamics triggered by a quench from the superfluid to normal phase across the Berezinskii-Kosterlitz-Thouless transition in a two-dimensional (2D) Bose gas. We reduced the density by splitting the 2D gas in two, realizing a quench across the critical point. The subsequent relaxation dynamics were probed with matter-wave interferometry to measure the local phase fluctuations. We show that the time evolution of both the phase correlation function and vortex density obeys universal scaling laws. This conclusion is supported by classical-field simulations and interpreted by means of real-time renormalization group theory.
DOI: abq6753
Source: https://www.science.org/doi/10.1126/science.abq6753