Nonthermal order by disorder

TL;DR

This paper investigates how nonequilibrium fluctuations can stabilize ordered states in systems with competing or cooperative orders, revealing a nonthermal order-by-disorder mechanism through theoretical analysis.

Contribution

It introduces a theoretical framework showing that fluctuations can stabilize nonthermal orders at transient states, extending the order-by-disorder concept to nonequilibrium dynamics.

Findings

Fluctuations can stabilize ordered states at transient free energy minima.

Nonthermal order-by-disorder mechanism is demonstrated theoretically.

Relevance to high-temperature superconductors and correlated materials.

Abstract

The quench dynamics of systems exhibiting cooperative or almost competitive orders in equilibrium are explored using Ginzburg-Landau theory plus fluctuations. We show that when the renormalization of the free energy by fluctuations is taken into account, anisotropic stiffnesses and relaxation rates of the order parameters can lead to a stabilization of ordered states at transient free energy minima which are distinct from any (global or local) minima of the equilibrium free energy. This theory demonstrates that nonequilibrium fluctuations play a pivotal role in forming nonthermal orders. As nonthermal order and nonthermal fluctuations mutually stabilize each other over some time, this mechanism could be seen as a nonequilibrium variant of the order-by-disorder phenomenon. We discuss the potential relevance of these findings for systems with intertwined orders, such as superconductivity and density wave orders, relevant for high-temperature superconductors and the kagome metals, as well as for systems that show orbital ordering.