Modified spin-wave theory and spin-liquid behavior of cold bosons on an inhomogeneous triangular lattice

Alessio Celi, Tobias Grass, Andrew J. Ferris, Bikash Padhi, David Raventós, Juliette Simonet, Klaus Sengstock, and Maciej Lewenstein

Phys. Rev. B 94, 075110 – Published 5 August 2016

Abstract

Ultracold bosons in a triangular lattice are a promising candidate for observing quantum spin liquid behavior. Here we investigate, for such system, the role of a harmonic trap giving rise to an inhomogeneous density. We construct a modified spin-wave theory for arbitrary filling and predict the breakdown of order for certain values of the lattice anisotropy. These regimes, identified with the spin liquid phases, are found to be quite robust upon changes in the filling factor. This result is backed by an exact diagonalization study on a small lattice.

12 More

Received 31 March 2016
Revised 19 June 2016

DOI:https://doi.org/10.1103/PhysRevB.94.075110

Physics Subject Headings (PhySH)

Cold atoms & matter waves Quantum spin liquid Spin waves

Atomic gases Synthetic gauge fields Topological phases of matter

Bose-Hubbard model Density matrix renormalization group Exact solutions for many-body systems Mean-field & cluster methods Semiclassical methods Spin lattice models Variational approach XY model

Atomic, Molecular & OpticalCondensed Matter, Materials & Applied Physics

Authors & Affiliations

Alessio Celi^1,*, Tobias Grass¹, Andrew J. Ferris¹, Bikash Padhi², David Raventós¹, Juliette Simonet^3,4, Klaus Sengstock^3,4, and Maciej Lewenstein^1,5

¹ICFO – Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels, Spain
²Department of Physics and Institute for Condensed Matter Theory, University of Illinois at Urbana-Champaign, Urbana, 61801 Illinois, USA
³Institut für Laserphysik, Universität Hamburg, Luruper Chaussee 149, D-22761 Hamburg, Germany
⁴Zentrum für Optische Quantentechnologien, Universität Hamburg, Luruper Chaussee 149, D-22761 Hamburg, Germany
⁵ICREA – Institució Catalana de Recerca i Estudis Avançats, Lluis Companys 23, 08010 Barcelona, Spain

^*alessio.celi@icfo.es

Article Text (Subscription Required)

Click to Expand

References (Subscription Required)

Click to Expand

Issue

Vol. 94, Iss. 7 — 15 August 2016

Reuse & Permissions

Access Options

Author publication services for translation and copyediting assistance advertisement

Physical Review B

covering condensed matter and materials physics