Fano resonance through Higgs bound states in tunneling of Nambu-Goldstone modes

Abstract

We study collective modes of superfluid Bose gases in optical lattices combined with potential barriers. We assume that the system is in the vicinity of the quantum phase transition to a Mott insulator at a commensurate filling, where emergent particle-hole symmetry gives rise to two types of collective mode, namely a gapless Nambu-Goldstone (NG) phase mode and a gapful Higgs amplitude mode. We consider two kinds of potential barrier: One does not break the particle-hole symmetry while the other does. In the presence of the former barrier, we find Higgs bound states that have binding energies lower than the bulk Higgs gap and are localized around the barrier. We analyze tunneling properties of the NG mode incident to both barriers to show that the latter barrier couples the Higgs bound states with the NG mode, leading to Fano resonance mediated by the bound states. Thanks to the universality of the underlying field theory, it is expected that Higgs bound states may be present also in other condensed matter systems with a particle-hole symmetry and spontaneous breaking of a continuous symmetry, such as quantum dimer antiferromagnets, superconductors, and charge-density-wave materials.

21 pages, 15 figures

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Cited by in corpus (12)

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• Stability of Standing Waves for a Nonlinear Klein-Gordon Equation with Delta Potentials
• Response of the Higgs amplitude mode of superfluid Bose gases in a three dimensional optical lattice
• Two-dimensional Schrödinger symmetry and three-dimensional breathers and Kelvin-ripple complexes as quasi-massive-Nambu-Goldstone modes
• Stability of supercurrents in a superfluid phase of spin-1 bosons in an optical lattice
• Perfect transmission of Higgs modes via antibound states
• Localized Higgs modes of superfluid Bose gases in optical lattices: A Guzwiller mean-field study
• Higgs and Nambu-Goldstone modes in condensed matter physics
• Hybridization of the amplitude mode in a confined fermionic superfluid
• Perfect transmission and perfect reflection of Bogoliubov quasiparticles in a dynamically unstable Bose-Einstein condensate
• Higgs and Nambu-Goldstone modes in a spin-1 $XY$ model with long-range interactions