# Control of effective free energy landscape in a frustrated magnet by a field pulse

## TL;DR

This paper demonstrates how a magnetic field pulse can manipulate the free energy landscape of a frustrated magnet, specifically a pyrochlore XY antiferromagnet, by exciting fast modes to control state stability.

## Contribution

It introduces a method to control the non-equilibrium free energy landscape in frustrated magnets using field pulses, linking fast mode excitation to slow ground state dynamics.

## Key findings

- Field pulses can create tunable free energy minima at unstable states.
- Fast mode excitation influences slow ground state motion.
- Control of non-equilibrium landscapes in frustrated magnets.

## Abstract

Thermal fluctuations can lift the degeneracy of a ground state manifold, producing a free energy landscape without accidentally degenerate minima. In a process known as order by disorder, a subset of states incorporating symmetry-breaking may be selected. Here, we show that such a free energy landscape can be controlled in a non-equilibrium setting as the slow motion within the ground state manifold is governed by the fast modes out of it. For the paradigmatic case of the classical pyrochlore XY antiferromagnet, we show that a uniform magnetic field pulse can excite these fast modes to generate a tunable effective free energy landscape with minima at thermodynamically unstable portions of the ground state manifold.