Work

Undamped Higgs Modes in Strongly Interacting Superconductors

Year: 2024

Type: article

Abstract: In superconductors gauge U(1) symmetry is spontaneously broken. According to Goldstone theorem this breaking of a continuous symmetry establishes the existence of the Bogoliubov phase mode while the gauge-invariant response also includes the amplitude fluctuations of the order parameter. The latter, which are also termed ’Higgs’ modes in analogy with the standard model, appear at the energy of the spectral gap 2Δ when the superconducting ground state is evaluated within the weak coupling BCS theory and are therefore damped. Previously we have shown that in the time-dependent Gutzwiller approximation (TDGA) Higgs modes appear inside the gap with a finite binding energy relative to the quasiparticle continuum. Here we show that the binding energy of the Higgs mode becomes exponentially small in the weak coupling limit converging to the BCS solution. On the other hand, well-defined undamped amplitude modes exist in strongly coupled superconductors when the interaction energy becomes of the order of the bandwidth.

Source: Condensed Matter

DOI: 10.3390/condmat9040038

Authors: Jose Lorenzana, Götz Seibold

Institutions: Institute for Complex Systems, National Research Council, Sapienza University of Rome, Brandenburg University of Technology Cottbus-Senftenberg

Language: English

Topic: Physics of Superconductivity and Magnetism

Subfield: Condensed Matter Physics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $1,819

Funder: Deutsche Forschungsgemeinschaft