Symmetry breaking and physical properties of the bosonic single-impurity Anderson model
arXiv:1405.3245 · doi:10.1140/epjb/e2012-30191-2
Abstract
We show how exact diagonalization of small clusters can be used as a fast and reliable impurity solver by determining the phase diagram and physical properties of the bosonic single-impurity Anderson model. This is specially important for applications which require the solution of a large number of different single-impurity problems, such as the bosonic dynamical mean field theory of disordered systems. In particular, we investigate the connection between spontaneous global gauge symmetry breaking and the occurrence of Bose-Einstein condensation (BEC). We show how BEC is accurately signaled by the appearance of broken symmetry, even when a fairly modest number of states is retained. The occurrence of symmetry breaking can be detected both by adding a small conjugate field or, as in generic quantum critical points, by the divergence of the associated phase susceptibility. Our results show excellent agreement with the considerably more demanding numerical renormalization group (NRG) method. We also investigate the mean impurity occupancy and its fluctuations, identifying an asymmetry in their critical behavior across the quantum phase transitions between BEC and `Mott' phases.
arXiv comment10 pages, 10 figures
References in corpus (23)
- Cold bosonic atoms in optical lattices
- The cold atom Hubbard toolbox
- A trapped single ion inside a Bose-Einstein condensate
- Atomic Bose and Anderson glasses in optical lattices
- A New Iterative Perturbation Scheme for Lattice Models with Arbitrary Filling
- Atomic quantum dots coupled to BEC reservoirs
- Phase Diagram of Bosonic Atoms in Two-Color Superlattices
- Matterwave localization in disordered cold atom lattices
- Observation of subdiffusion of a disordered interacting system
- Magnetic phases of two-component ultracold bosons in an optical lattice
- Correlated bosons on a lattice: Dynamical mean-field theory for Bose-Einstein condensed and normal phases
- Ultracold atoms in optical lattices with random on-site interactions
- Dynamical mean field solution of the Bose-Hubbard model
- Bose-Einstein condensation and gauge symmetry breaking
- Atom cooling and trapping by disorder
- Three-dimensional strong localization of matter waves by scattering from atoms in a lattice with a confinement-induced resonance
- Dynamical mean-field theory for bosons
- Dynamical Mean Field Theory for the Bose-Hubbard Model
- Stochastic Mean-Field Theory: Method and Application to the Disordered Bose-Hubbard Model at Finite Temperature and Speckle Disorder
- Dynamical mean-field studies of metal-insulator transitions
- Quantum Phase Transitions in the Bosonic Single-Impurity Anderson Model
- Excitations in disordered bosonic optical lattices
- NRG for the bosonic single-impurity Anderson model: Dynamics