Mott insulators in strong electric fields

Sachdev, Subir; Sengupta, K.; Girvin, S. M.

doi:10.1103/physrevb.66.075128

Cited by 214 publications

(318 citation statements)

References 17 publications

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“…Such correlations can be probed, for example, by tilting the optical lattice with a potential gradient 1 . Deep inside the Mott phase, such a potential gradient will excite the system only if E = E dipole , where E is the potential energy shift between adjacent lattice due to the field gradient and E dipole is the dipole formation energy 1,26 . The dipole formation energy will sharply change across the phase transition lines between AFM-XY and AFM-FM phases and consequently the peak in the excitation width, measured in Ref.…”

Section: Detecting the Different Phasesmentioning

confidence: 99%

Superfluid-insulator transitions of two-species bosons in an optical lattice

et al. 2005

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We consider a realization of the two-species bosonic Hubbard model with variable interspecies interaction and hopping strength. We analyze the superfluid-insulator (SI) transition for the relevant parameter regimes and compute the ground state phase diagram for odd filling at commensurate densities. We find that in contrast to the even commensurate filling case, the superfluid-insulator transition occurs with (a) simultaneous onset of superfluidity of both species or (b) coexistence of Mott insulating state of one species and superfluidity of the other or, in the case of unit filling, (c) complete depopulation of one species. The superfluid-insulator transition can be first order in a large region of the phase diagram. We develop a variational mean-field method which takes into account the effect of second order quantum fluctuations on the superfluid-insulator transition and corroborate the mean-field phase diagram using a quantum Monte Carlo study.

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Section: Detecting the Different Phasesmentioning

confidence: 99%

Superfluid-insulator transitions of two-species bosons in an optical lattice

et al. 2005

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“…15,43 The mean-field theory of Fisher et al 13 and its generalization to spinful bosons were widely used to investigate quantum phase transitions and the phase diagrams of correlated lattice boson systems and of mixtures of lattice bosons and fermions. 3,4,5,6,7,8,44,45,46 Eq. (21) and (22) can also be obtained directly from the B-DMFT self-consistency equations by neglecting the hybridization function, i.e.…”

Section: B Immobile Bosons ("Atomic Limit")mentioning

confidence: 99%

Correlated bosons on a lattice: Dynamical mean-field theory for Bose-Einstein condensed and normal phases

2008

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We formulate a bosonic dynamical mean-field theory (B-DMFT) which provides a comprehensive, thermodynamically consistent framework for the theoretical investigation of correlated lattice bosons. The B-DMFT is applicable for arbitrary values of the coupling parameters and temperature and becomes exact in the limit of high spatial dimensions d or coordination number Z of the lattice. In contrast to its fermionic counterpart the construction of the B-DMFT requires different scalings of the hopping amplitudes with Z depending on whether the bosons are in their normal state or in the Bose-Einstein condensate. A detailed discussion of how this conceptual problem can be overcome by performing the scaling in the action rather than in the Hamiltonian itself is presented. The B-DMFT treats normal and condensed bosons on equal footing and thus includes the effects caused by their dynamic coupling. It reproduces all previously investigated limits in parameter space such as the Beliaev-Popov and Hartree-Fock-Bogoliubov approximations and generalizes the existing mean-field theories of interacting bosons. The self-consistency equations of the B-DMFT are those of a bosonic single-impurity coupled to two reservoirs corresponding to bosons in the condensate and in the normal state, respectively. We employ the B-DMFT to solve a model of itinerant and localized, interacting bosons analytically. The local correlations are found to enhance the condensate density and the Bose-Einstein condensate (BEC) transition temperature TBEC. This effect may be used experimentally to increase TBEC of bosonic atoms in optical lattices.

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“…This model is of great theoretical interest since it exhibits a quantum phase transition [8,9,10,11] between ground states where the atoms are localized (Mott-Insulator) and where they are delocalized (superfluid) as the strength of the hopping relative to the inter-atomic interaction is varied. The dynamics of particles under the influence of changes in the Hamiltonian (such as lattice tilts or rapid changes in the particle interaction strength) has also proved interesting [4,5,6,12,13].…”

Section: Introductionmentioning

confidence: 99%

Multiflavor bosonic Hubbard models in the first excited Bloch band of an optical lattice

2005

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We propose that by exciting ultra cold atoms from the zeroth to the first Bloch band in an optical lattice, novel multi-flavor bosonic Hubbard Hamiltonians can be realized in a new way. In these systems, each flavor hops in a separate direction and on-site exchange terms allow pairwise conversion between different flavors. Using band structure calculations, we determine the parameters entering these Hamiltonians and derive the mean field ground state phase diagram for two effective Hamiltonians (2D, two-flavors and 3D, three flavors). Further, we estimate the stability of atoms in the first band using second order perturbation theory and find lifetimes that can be considerably (10-100 times) longer than the relevant time scale associated with inter-site hopping dynamics, suggesting that quasi-equilibrium can be achieved in these meta-stable states.

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Mott insulators in strong electric fields

Cited by 214 publications

References 17 publications

Superfluid-insulator transitions of two-species bosons in an optical lattice

Superfluid-insulator transitions of two-species bosons in an optical lattice

Correlated bosons on a lattice: Dynamical mean-field theory for Bose-Einstein condensed and normal phases

Multiflavor bosonic Hubbard models in the first excited Bloch band of an optical lattice

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