Quantum Quenches of an SO(5) Pseudospin Reveal Higgs Bosons

TL;DR

This paper proposes dynamical quench protocols to excite and detect all ten Higgs bosons in an SO(5) pseudospin model of a spinful p-wave superfluid or superconductor, revealing their collective excitations.

Contribution

It introduces a method to selectively excite all Higgs modes in an SO(5) pseudospin system using symmetry-breaking quenches, extending previous approaches.

Findings

Periodic oscillations of Higgs modes observed in simulations.

Protocols exploit angular momentum representation to target specific modes.

Potential experimental realization discussed for superfluids and superconductors.

Abstract

Controlled dynamical probe measurement of complex order parameter fluctuations may reveal its massive collective excitations. Here, we design dynamical quench protocols to excite independently all ten midgap Higgs bosons in the isotropic Balian--Werthamer state of a spinfull $p$-wave superfluid or superconductor. The analysis is based on microscopic equations of motion of an SO(5) pseudospin, an extension of the usual Bloch equation to a five dimensional space. Key to these protocols is the realization of quenches that break the rotational symmetry of the kinetic energy and exploit the irreducible representation of the angular momentum $J=2$. For perturbative quenches, we find (non-decaying) periodic oscillations in time of these Higgs modes. Experiments to realize our proposal for either superfluids or superconductors are considered.