Collective modes in superconductors including Coulomb repulsion
arXiv:2503.05494 · doi:10.21468/SciPostPhys.19.3.067
Abstract
We numerically study the collective excitations present in isotropic superconductors including a screened Coulomb interaction. By varying the screening strength, we analyze its impact on the system. We use a formulation of the effective phonon-mediated interaction between electrons that depends on the energy transfer between particles, rather than being a constant in a small energy shell around the Fermi edge. This justifies considering also rather large attractive interactions. We compute the system's Green's functions using the iterated equations of motion (iEoM) approach, which ultimately enables a quantitative analysis of collective excitations. For weak couplings, we identify the well-known amplitude (Higgs) mode at the two-particle continuum's lower edge and the phase (Anderson-Bogoliubov) mode at for a neutral system, which shifts to higher energies as the Coulomb interaction is switched on. As the phononic coupling is increased, the Higgs mode separates from the continuum, and additional phase and amplitude modes appear, persisting even in the presence Coulomb interactions.
arXiv comment29 pages, 15 figures Update: More detailed explanations and clarifications. Three new references
References in corpus (32)
- Theory of Anderson pseudospin resonance with Higgs mode in superconductors
- Amplitude `Higgs' mode in 2H-NbSe2 Superconductor
- Coupling of Higgs and Leggett modes in nonequilibrium superconductors
- Classification and characterization of nonequilibrium Higgs modes in unconventional superconductors
- Collective modes and terahertz near-field response of superconductors
- Nature and Raman signatures of the Higgs amplitude mode in the coexisting superconducting and charge-density-wave state
- Flow Equations for Electron-Phonon Interactions
- Enhanced Perturbative Continuous Unitary Transformations
- A balancing act: Evidence for a strong subdominant d-wave pairing channel in
- Interaction Quenches of Fermi Gases
- Collective modes in superconductors with competing s- and d-wave interactions
- Similarity renormalization of the electron--phonon coupling
- Dynamical Transition in Interaction Quenches of the One-Dimensional Hubbard Model
- Calculating critical temperatures of superconductivity from a renormalized Hamiltonian
- Interaction quenches in the two-dimensional fermionic Hubbard model
- Eliashberg theory of superconductivity and inelastic rare-earth impurity scattering in filled skutterudite LaPrOsSb
- Bardasis-Schrieffer polaritons in excitonic insulators
- High-order nonlinear terahertz probing of the two-band superconductor MgB: Third- and fifth-order harmonic generation
- Short-distance breakdown of the Higgs mechanism and the robustness of the BCS theory for charged superconductors
- Theory for phonon-induced superconductivity in MgB
- Renormalization of the electron-phonon interaction: a reformulation of the BCS-gap equation
- Continuous similarity transformation for critical phenomena: easy-axis antiferromagnetic XXZ model
- Characterization of collective excitations in weakly-coupled disordered superconductors
- Efficient flow equations for dissipative systems
- Comparison of the Iterated Equation of Motion Approach and the Density Matrix Formalism for the Quantum Rabi Model
- Collisionless dynamics in disordered superconductors
- Excitation of the dissipationless Higgs mode in a fermionic condensate
- Bardasis-Schrieffer-like phase mode in a superconducting bilayer
- Quantum melting of long-range ordered quantum antiferromagnets investigated by momentum-space continuous similarity transformations
- Collective excitations in competing phases in two and three dimensions
- Optical Pumping of Bardeen-Cooper-Schrieffer Superconductors
- Signatures of Bardasis-Schrieffer mode excitation in Third-Harmonic generated currents