Title:
|
Fragmented condensation in Bose–Hubbard trimers with tunable tunnelling
|
Author:
|
Gallemí, A.; Guilleumas, M.; Martorell, J.; Mayol, R.; Polls, A.; Juliá-Díaz, Bruno
|
Other authors:
|
Universitat Politècnica de Catalunya. Institut de Ciències Fotòniques |
Abstract:
|
We consider a Bose–Hubbard (BH) trimer, i.e. an ultracold Bose gas populating three quantum states. The latter can be either different sites of a triple-well potential or three internal states of the atoms. The bosons can tunnel between different states with variable tunnelling strength between two of them. This will allow us to study; (i) different geometrical configurations, i.e. from a closed triangle to three aligned wells and (ii) a triangular configuration with a π-phase, i.e. by setting one of the tunnellings negative. By solving the corresponding three-site BH Hamiltonian we obtain the ground state of the system as a function of the trap topology. We characterize the different ground states by means of the coherence and entanglement properties. For small repulsive interactions, fragmented condensates are found for the π-phase case. These are found to be robust against small variations of the tunnelling in the small interaction regime. A low-energy effective many-body Hamiltonian restricted to the degenerate manifold provides a compelling description of the π-phase degeneration and explains the low-energy spectrum as excitations of discrete semifluxon states. |
Abstract:
|
Peer Reviewed |
Subject(s):
|
-Àrees temàtiques de la UPC::Física -Quantum optics -Condensation -Òptica quàntica |
Rights:
|
Attribution-NonCommercial-NoDerivs 3.0 Spain
http://creativecommons.org/licenses/by-nc-nd/3.0/es/ |
Document type:
|
Article - Published version Article |
Published by:
|
IOP
|
Share:
|
|