August 31, 1998 | D. Jaksch, C. Bruder, J. I. Cirac, C.W. Gardiner and P. Zoller
This paper discusses the dynamics of ultracold bosonic atoms in optical lattices, which can be described by the Bose-Hubbard model (BHM). The model describes the hopping of bosonic atoms between lattice sites and the onsite repulsion between them. The system parameters are controlled by laser light, and the optical lattice potential can be varied to induce a quantum phase transition from a superfluid (SF) phase to a Mott insulator (MI) phase. The MI phase corresponds to a commensurate filling of the lattice, with integer occupation numbers per site.
The BHM predicts a phase transition from SF to MI at low temperatures, with the transition occurring when the ratio of onsite interaction U to tunneling matrix element J increases. The optical lattice potential can be adjusted by changing the laser intensity, which affects the localization of the atomic wave function and the tunneling matrix element. In the MI phase, the density is pinned at integer values, and the system exhibits diagonal long-range order.
The paper presents a Hamiltonian for bosonic atoms in an external trapping potential, which is expanded in the Wannier basis to derive the BHM. The parameters U and J are evaluated numerically for the given optical potential. The paper also discusses the role of collisions between ground state atoms as a loss and decoherence mechanism, and the importance of minimizing these collisions in the MI phase.
The authors perform mean-field calculations for 1D and 2D configurations and exact diagonalization of the BH Hamiltonian in 1D to illustrate the formation of the MI phase. The results show that the MI phase is indicated by single Fock states and integer occupation numbers. The paper also discusses the formation of Mott structures in optical lattices with a superimposed harmonic trap and in optical superlattices.
The paper concludes that the ability to manipulate both the lattice and system parameters in the BHM brings new insights to condensed matter physics, allowing for the systematic investigation of models and simplifying assumptions using quantum optics techniques.This paper discusses the dynamics of ultracold bosonic atoms in optical lattices, which can be described by the Bose-Hubbard model (BHM). The model describes the hopping of bosonic atoms between lattice sites and the onsite repulsion between them. The system parameters are controlled by laser light, and the optical lattice potential can be varied to induce a quantum phase transition from a superfluid (SF) phase to a Mott insulator (MI) phase. The MI phase corresponds to a commensurate filling of the lattice, with integer occupation numbers per site.
The BHM predicts a phase transition from SF to MI at low temperatures, with the transition occurring when the ratio of onsite interaction U to tunneling matrix element J increases. The optical lattice potential can be adjusted by changing the laser intensity, which affects the localization of the atomic wave function and the tunneling matrix element. In the MI phase, the density is pinned at integer values, and the system exhibits diagonal long-range order.
The paper presents a Hamiltonian for bosonic atoms in an external trapping potential, which is expanded in the Wannier basis to derive the BHM. The parameters U and J are evaluated numerically for the given optical potential. The paper also discusses the role of collisions between ground state atoms as a loss and decoherence mechanism, and the importance of minimizing these collisions in the MI phase.
The authors perform mean-field calculations for 1D and 2D configurations and exact diagonalization of the BH Hamiltonian in 1D to illustrate the formation of the MI phase. The results show that the MI phase is indicated by single Fock states and integer occupation numbers. The paper also discusses the formation of Mott structures in optical lattices with a superimposed harmonic trap and in optical superlattices.
The paper concludes that the ability to manipulate both the lattice and system parameters in the BHM brings new insights to condensed matter physics, allowing for the systematic investigation of models and simplifying assumptions using quantum optics techniques.