Following the Higgs mode across the BCS-BEC crossover in two dimensions

Abstract

Although substantial effort has been dedicated to analyzing the Higgs (amplitude) mode in superconducting systems, there are relatively few studies of the Higgs peak's dispersion and width, quantities which are observable in spectroscopic measurements. These properties can be obtained from the location of the pole of the longitudinal (Higgs) susceptibility in the lower half-plane of complex frequency. We analyze the behavior of the Higgs mode in a 2D neutral fermionic superfluid at $T=0$ throughout the crossover from Bardeen-Cooper-Schrieffer (BCS) to Bose-Einstein condensation (BEC) behavior. This occurs when the dressed chemical potential $\mu$ changes sign from positive to negative. For $\mu >0$, we find a pole in the Higgs susceptibility in the lower half-plane of frequency and demonstrate that it leads to a well-defined peak in spectroscopic probes. For $\mu <0$, the pole still exists, but is "hidden," not giving rise to a peak in spectroscopic probes. Extending this analysis to a charged superconductor, we find that the Higgs mode is unaffected by the long-range Coulomb interaction.

References in corpus (42)

• Amplitude / Higgs Modes in Condensed Matter Physics
• The `Higgs' Amplitude Mode at the Two-Dimensional Superfluid-Mott Insulator Transition
• Higgs Mode in Superconductors
• Quantum Fluctuations in the Superfluid State of the BCS-BEC Crossover
• Visibility of the Amplitude (Higgs) Mode in Condensed Matter
• Collective mode of homogeneous superfluid Fermi gases in the BEC-BCS crossover
• Amplitude `Higgs' mode in 2H-NbSe2 Superconductor
• Non-linear optical effects and third-harmonic generation in superconductors: Cooper-pairs vs Higgs mode contribution
• Higgs mode in the d-wave superconductor Bi2Sr2CaCu2O8+x driven by an intense terahertz pulse
• Spectral functions of the Higgs mode near two-dimensional quantum critical points
• The Higgs mode in a two-dimensional superfluid
• Polarization-resolved terahertz third-harmonic generation in a superconductor NbN: dominance of Higgs mode beyond the BCS approximation
• Higgs mode in a strongly interacting fermionic superfluid
• Amplitude Higgs mode and admittance in superconductors with a moving condensate
• Superconductivity vs bound state formation in a two-band superconductor with small Fermi energy -- applications to Fe-pnictides/chalcogenides and doped SrTiO3
• Pressure induced collapse of the charge density wave and Higgs mode visibility in 2H-TaS${}_2$
• Fate of the Higgs mode near quantum criticality
• Nature and Raman signatures of the Higgs amplitude mode in the coexisting superconducting and charge-density-wave state
• Non-relativistic dynamics of the amplitude (Higgs) mode in superconductors
• Nonreciprocal Terahertz Second Harmonic Generation in Superconducting NbN under Supercurrent Injection
• Higgs-mode radiance and charge-density-wave order in 2H-NbSe${}_2$
• Higgs amplitude mode in the vicinity of a $(2+1)$-dimensional quantum critical point
• Direct observation of the Higgs amplitude mode in a two-dimensional quantum antiferromagnet near the quantum critical point
• Higgs amplitude mode in the vicinity of a $(2+1)$-dimensional quantum critical point: a nonperturbative renormalization-group approach
• Pair-Breaking Collective Branch in BCS Superconductors and Superfluid Fermi Gases
• Superconducting fluctuations probed by the Higgs mode in Bi${}_2$Sr${}_2$CaCu${}_2$O${}_{8+x}$ thin films
• Theory of driven Higgs oscillations and third-harmonic generation in unconventional superconductors
• Universal Properties of the Higgs Resonance in (2+1)-Dimensional U(1) Critical Systems
• Coherence length in superconductors from weak to strong coupling
• Conservation laws, vertex corrections, and screening in Raman spectroscopy
• Phononic collective excitations in superfluid Fermi gases at nonzero temperatures
• Spectral function of the Higgs mode in 4-\varepsilon dimensions
• Dynamical structure factors of a two-dimensional Fermi superfluid within random phase approximation
• Collective excitation branch in the continuum of pair-condensed Fermi gases : analytical study and scaling laws
• Collective excitations of superfluid Fermi gases near the transition temperature
• Calculation of an enhanced A1g symmetry mode induced by Higgs oscillations in the Raman spectrum of high-temperature cuprate superconductors
• Leggett collective excitations in a two-band Fermi superfluid at finite temperatures
• Collective density fluctuations of strange metals with critical Fermi surfaces
• Quantum phase transition in a clean superconductor with repulsive dynamical interaction
• Comment on: Calculation of an Enhanced $A_{1g}$ Symmetry Mode Induced by Higgs Oscillations in the Raman Spectrum of High-Temperature Cuprate Superconductors
• Dispersion of plasmons in three-dimensional superconductors
• Dynamic properties of superconductors: Anderson-Bogoliubov mode and Berry phase in BCS and BEC regimes

Cited by in corpus (8)

• Nonlinear Response of Diffusive Superconductors to $ac$-electromagnetic Fields
• The Condensation of Ideal Dunkl-Bose Gas in Power-Law Traps
• Spatially-resolved dynamics of the amplitude Schmid-Higgs mode in disordered superconductors
• Dynamic structure factor of two-dimensional Fermi superfluid with Rashba spin-orbit coupling
• Quantum Fluctuations and Multifractally-Enhanced Superconductivity in Disordered Thin Films
• Spectrum of density, spin and pairing fluctuations of an attractive two-dimensional Fermi gas
• Spatially resolved collective modes in d-wave superconductors
• AC Josephson Signatures of the Superconducting Higgs Mode