Demonstrating Universal Scaling in Quench Dynamics of a Yukawa One-Component Plasma

TL;DR

This study shows that ultracold neutral plasmas exhibit universal quench dynamics governed solely by the screening parameter, regardless of initial density and temperature, confirmed through experiments and molecular dynamics simulations.

Contribution

The paper demonstrates universal scaling in the quench dynamics of Yukawa one-component plasmas using ultracold neutral plasmas, linking dynamics solely to the screening parameter $ppa$.

Findings

Post-quench dynamics are universal over a wide range of densities and temperatures.

Features like disorder-induced heating and energy oscillations reveal plasma parameters.

Experimental results agree with molecular dynamics simulations.

Abstract

The Yukawa one-component plasma (OCP) is a paradigm model for describing plasmas that contain one component of interest and one or more other components that can be treated as a neutralizing, screening background. In appropriately scaled units, interactions are characterized entirely by a screening parameter, $\kappa$. As a result, systems of similar $\kappa$ show the same dynamics, regardless of the underlying parameters (e.g., density and temperature). We demonstrate this behavior using ultracold neutral plasmas (UNP) created by photoionizing a cold ($T\le10$ mK) gas. The ions in UNP systems are well described by the Yukawa model, with the electrons providing the screening. Creation of the plasma through photoionization can be thought of as a rapid quench from $\kappa_{0}=\infty$ to a final $\kappa$ value set by the electron density and temperature. We demonstrate experimentally that the post-quench dynamics are universal in $\kappa$ over a factor of 30 in density and an order of magnitude in temperature. Results are compared with molecular dynamics simulations. We also demonstrate that features of the post-quench kinetic energy evolution, such as disorder-induced heating and kinetic-energy oscillations, can be used to determine the plasma density and the electron temperature.