Variational cluster approach for strongly correlated lattice bosons in the superfluid phase
arXiv:1010.4295 · doi:10.1103/PhysRevB.83.134507
Abstract
We extend the variational cluster approach to deal with strongly correlated lattice bosons in the superfluid phase. To this end, we reformulate the approach within a pseudoparticle formalism, whereby cluster excitations are described by particlelike excitations. The approximation amounts to solving a multicomponent noninteracting bosonic system by means of a multimode Bogoliubov approximation. A source-and-drain term is introduced in order to break U(1) symmetry at the cluster level. We provide an expression for the grand potential, the single-particle normal and anomalous Green's functions, the condensate density, and other static quantities. As a first nontrivial application of the method we choose the two-dimensional Bose-Hubbard model and evaluate results in both the Mott and the superfluid phases. Our results show an excellent agreement with quantum Monte Carlo calculations.
15 pages, 5 figures
References in corpus (18)
- Many-Body Physics with Ultracold Gases
- Quantum phase transition from a superfluid to a Mott insulator in a gas of ultracold atoms
- The ALPS project release 1.3: open source software for strongly correlated systems
- Quantum Many-Body Phenomena in Coupled Cavity Arrays
- Variational cluster approach to correlated electron systems in low dimensions
- Generalized Directed Loop Method for Quantum Monte Carlo Simulations
- Mott insulator to superfluid transition in the Bose-Hubbard model: a strong-coupling approach
- Variational cluster approach to spontaneous symmetry breaking: The itinerant antiferromagnet in two dimensions
- Self-energy-functional approach: Analytical results and the Mott-Hubbard transition
- Dynamical properties of ultracold bosons in an optical lattice
- Many-body phenomena in QED-cavity arrays
- Variational cluster approach to the Hubbard model: Phase-separation tendency and finite-size effects
- Quantum Fluctuations, Temperature and Detuning Effects in Solid-Light Systems
- Spectral weight redistribution in strongly correlated bosons in optical lattices
- Gapless Hartree-Fock-Bogoliubov Approximation for Bose Gases
- Non-perturbative conserving approximations and Luttinger's sum rule
- Benchmarking the variational cluster approach by means of the one-dimensional Bose-Hubbard model
- Conserving and gapless approximations for the composite bosons in terms of the constituent fermions
Cited by in corpus (8)
- Characterization of Mott-insulating and superfluid phases in the one-dimensional Bose--Hubbard model
- Non-equilibrium cluster-perturbation theory
- Quenching from superfluid to free bosons in two dimensions: entanglement, symmetries, and quantum Mpemba effect
- Spectral properties and phase diagram of correlated lattice bosons in an optical cavity within the B-DMFT
- Numerical calculation of spectral functions of the Bose-Hubbard model using B-DMFT
- Thermodynamics of the Bose-Hubbard model in a Bogoliubov+U theory
- Variational Cluster Approximation to the Thermodynamics of Quantum Spin Systems
- Strong-coupling RPA theory of a Bose gas near the superfluid--Mott-insulator transition: universal thermodynamics and two-body contact