Fermi points and the Nambu sum rule in the polar phase of He
arXiv:1705.02231 · doi:10.1134/S0021364017110029
Abstract
We discuss the polar phase of He, which is realized in the anisotropic aerogel. We consider it in the framework of the BCS model. In the absence of the spin - orbit interaction this model predicts the appearance of the Fermi line. However, it is topologically unstable. We demonstrate, that the spin - orbit interaction gives rise to the appearance of the two Fermi points instead of the Fermi line. In addition to the gapless Nambu - Goldstone bosons in this system the collective gapped bosonic states exist. Their gaps are calculated, and the corresponding Nambu sum rule is established.
Latex, 5 pages, with the Supplemental material, 6 pages
References in corpus (16)
- Dirac Line Nodes in Inversion Symmetric Crystals
- Topological Nodal Line Semimetal and Dirac Semimetal State in Antiperovskite CuPdN
- Topological Node-Line Semimetal in Three Dimensional Graphene Networks
- Amplitude / Higgs Modes in Condensed Matter Physics
- Potential ring of Dirac nodes in a new polymorph of CaP
- The Higgs Mode in Disordered Superconductors Close to a Quantum Phase Transition
- Dimensional crossover in topological matter: Evolution of the multiple Dirac point in the layered system to the flat band on the surface
- Observation of half-quantum vortices in topological superfluid 3He
- Polar phase of superfluid 3He in anisotropic aerogel
- Direct observation of Higgs mode oscillations in the pump-probe photoemission spectra of electron-phonon mediated superconductors
- Band-Contact Lines in Electron Energy Spectrum of Graphite
- On Nambu's Fermion-Boson Relations for Superfluid He-B
- Quasi-Nambu-Goldstone modes in nonrelativistic systems
- Anisotropic 2D Larkin-Imry-Ma state in polar distorted ABM phase of 3He in "nematically ordered" aerogel
- Half-quantum vortices in polar phase of superfluid He-3
- Nambu identity and collective modes in superconductors and superfluid He