Amplitude modes and dynamic coexistence of competing orders in multicomponent superconductors

TL;DR

This paper investigates the nonequilibrium dynamics of multicomponent superconductors with competing orders, revealing that magnetic and superconducting states can coexist dynamically after a quench, with distinct oscillatory modes.

Contribution

It introduces a theoretical framework to analyze the nonadiabatic dynamics of competing orders in multicomponent superconductors, showing dynamic coexistence and identifying amplitude modes.

Findings

Dynamic coexistence of magnetic and superconducting orders after a quench

Identification of incommensurate oscillatory amplitude modes

Exact solutions for certain nonadiabatic quench scenarios

Abstract

We study the nonequilibrium dynamics of an electronic model with competing spin-density-wave and unconventional superconductivity in the context of iron pnictides. Focusing on the collisionless regime, we find that magnetic and superconducting order parameters may coexist dynamically after a sudden quench, even though the equilibrium thermodynamic state supports only one order parameter. We consider various initial conditions concomitant with the phase diagram and in a certain regime identify different oscillatory amplitude modes with incommensurate frequencies for magnetic and superconducting responses. At the technical level we solve the equations of motion for the electronic Green's functions and self-consistency conditions by reducing the problem to a closed set of Bloch equations in a pseudospin representation. For certain quench scenarios the nonadiabatic dynamics of the pairing amplitude is completely integrable and in principle can be found exactly.