Continuous unitary transformations in two-level boson systems
Statistical Mechanics
2007-05-23 v3 Nuclear Theory
Quantum Physics
Abstract
Two-level boson systems displaying a quantum phase transition from a spherical (symmetric) to a deformed (broken) phase are studied. A formalism to diagonalize Hamiltonians with symmetry for large number of bosons is worked out. Analytical results beyond the simple mean-field treatment are deduced by using the continuous unitary transformations technique. In this scheme, a 1/N expansion for different observables is proposed and allows one to compute the finite-size scaling exponents at the critical point. Analytical and numerical results are compared and reveal the power of the present approach to compute the finite-size corrections in such a context.
Cite
@article{arxiv.cond-mat/0509721,
title = {Continuous unitary transformations in two-level boson systems},
author = {S. Dusuel and J. Vidal and J. M. Arias and J. Dukelsky and J. E. Garcia-Ramos},
journal= {arXiv preprint arXiv:cond-mat/0509721},
year = {2007}
}
Comments
27 pages, 16 figures, published version