2021/04/20 by Shunji Tsuchiya, Tsuchiya, Shunji
Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Theory (hep-th) #Physics of Superconductivity and Magnetism #Quantum Gases (cond-mat.quant-gas) #Quantum and electron transport phenomena #Quantum many-body systems #Strongly Correlated Electrons (cond-mat.str-el) #Superconductivity (cond-mat.supr-con)
paper · pdf · doi:10.48550/arxiv.2104.09744
openalex publication_date 2021/04/20 · openalex created_date 2021/09/13 · openalex updated_date 2026/07/28
We study the Higgs mode in a Bardeen-Cooper-Schrieffer (BCS) superconductor. Motivated by the observation that U(1) symmetry of the BCS Hamiltonian is not essential for the Higgs mode, we study the Ising-like Hamiltonian in the pseudospin representation. We show that the Higgs mode emerges as the lowest excited state of the Ising-like Hamiltonian due to spontaneous breakdown of ℤ2 symmetry under the time-reversal operation \mathcal T in the pseudospin space. We further predict the existence of multiple Higgs modes that have quantized energy 2(n+1)Δ0 (0≤ n≤ NkF), where Δ0 is the superconducting gap, n is an integer, and NkF is the number of states on the Fermi surface.