| Full text | |
| Author(s): |
Total Authors: 2
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| Affiliation: | [1] Inst Fis Gleb Wataghin, BR-13083859 Campinas, SP - Brazil
Total Affiliations: 1
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| Document type: | Journal article |
| Source: | European Physical Journal B; v. 85, n. 10 OCT 2012. |
| Web of Science Citations: | 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. (AU) | |
| FAPESP's process: | 07/57630-5 - Non-perturbative methods applied to strongly correlated electronic systems |
| Grantee: | Eduardo Miranda |
| Support Opportunities: | Research Projects - Thematic Grants |