Particle-Hole Character of the Higgs and Goldstone Modes in Strongly Interacting Lattice Bosons

Year: 2018

Authors: Di Liberto M., Recati A., Trivedi N., Carusotto I., Menotti C.

Autors Affiliation: [Di Liberto, M.; Recati, A.; Carusotto, I.; Menotti, C.] INO CNR BEC Ctr, I-38123 Povo, Italy and Univ Trento, Dipartimento Fis, I-38123 Povo, Italy.
[Recati, A.] Ludwigs Maximillian Univ Munchen, Arnold Sommerfeld Ctr Theoret Phys, D-80333 Munich, Germany.
[Trivedi, N.] Ohio State Univ, Dept Phys, Columbus, OH 43210 USA.

Abstract: We study the low-energy excitations of the Bose-Hubbard model in the strongly interacting superfluid phase using a Gutzwiller approach. We extract the single-particle and single-hole excitation amplitudes for each mode and report emergent mode-dependent particle-hole symmetry on specific arc-shaped lines in the phase diagram connecting the well-known Lorentz-invariant limits of the Bose-Hubbard model. By tracking the in-phase particle-hole symmetric oscillations of the order parameter, we provide an answer to the long-standing question about the fate of the pure amplitude Higgs mode away from the integer-density critical point. Furthermore, we point out that out-of-phase symmetric oscillations in the gapless Goldstone mode are responsible for a full suppression of the condensate density oscillations. Possible detection protocols are also discussed.


Volume: 120 (7)      Pages from: 073201-1  to: 073201-6

More Information: The authors would like to thank T. Comparin, C. Giannetti, L. Pollet, and M. Punk for useful discussions. This work was supported by the EU-FET Proactive grant AQuS, Project No. 640800 and by Provincia Autonoma di Trento. N.T. acknowledges funding from NSF-DMR-1309461.
KeyWords: Bose-Hubbard model, Quantum Phase Transition, Higgs modes
DOI: 10.1103/PhysRevLett.120.073201

Citations: 8
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