Diagrams of State for One-Dimensional Hydrogen-Bonded Proton Conductor

Stasyuk, I. V.; Vorobyov, O.; Stetsiv, R. Ya.

doi:10.1080/00150193.2012.671087

“…The behaviour of ρ A (ω) function is in agreement with the results of numerical calculations performed in [19] with exact diagonalization technique for one-dimensional (d = 1) chain structures. In [19], the authors take into account the two-particle interaction between nearest neighbouring sites. This interaction forms the effective internal field which is similar to the field δ considered here, and both fields are responsible for the appearance of CDW-like phase.…”

Section: Excitation Spectrum In Sf Phasesupporting

confidence: 84%

Energy spectrum and phase diagrams of two-sublattice hard-core boson model

Stasyuk¹,

Vorobyov²

2013

Condens. Matter Phys.

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The energy spectrum, spectral density and phase diagrams have been obtained for two-sublattice hard-core boson model in frames of random phase approximation approach. Reconstruction of boson spectrum at the change of temperature, chemical potential and energy difference between local positions in sublattices is studied. The phase diagrams illustrating the regions of existence of a normal phase which can be close to Mottinsulator (MI) or charge-density (CDW) phases as well as the phase with the Bose-Einstein condensate (SF phase) are built.

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“…The character of changes in the frequency dependence of the one-particle spectral density of states, which depends on the location of the chemical potential level, qualitatively agrees with the results of calculations obtained in the framework of the exact diagonalization technique for the one-dimensional chain model [23]. In the cited work, the hoppings of hard-core bosons onto neighbor sites were considered, and negative values were obtained for the one-particle spectral densities at energies located below the chemical potential level.…”

Section: Spectrum Of Bosonic Excitations One-particle Spectral Densisupporting

confidence: 75%

“…In the framework of the pseudospin approach, by applying the fermionization procedure in the one-dimensional case [21] and the random phase approximation in the more general three-dimensional one [22], modifications in the one-particle spectral densities at the transition from the non-ordered (NO) state into the ordered one, in which S x = b + = b = 0 and which is an analog of the phase with the lattice Bose condensate (the SF phase), were studied. The spectral densities and their frequency dependences obtained in work [22] qualitatively agree with the corresponding frequency dependences calculated on the basis of the fermionization model and using the method of exact diagonalization at one-dimensional clusters [23].…”

Section: Introductionsupporting

confidence: 71%

“…This work continues our theoretical researches [21][22][23][24] dealing with the energy spectrum and the spectral characteristics of a quantum lattice Bose gas, and, in particular, the hard-core boson model. In the framework of the pseudospin approach, by applying the fermionization procedure in the one-dimensional case [21] and the random phase approximation in the more general three-dimensional one [22], modifications in the one-particle spectral densities at the transition from the non-ordered (NO) state into the ordered one, in which S x = b + = b = 0 and which is an analog of the phase with the lattice Bose condensate (the SF phase), were studied.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Investigation of the Bosonic Spectrum of Two-Dimensional Optical Graphene-Type Lattices. Normal Phase

Stasyuk

¹

,

Dulepa

²

,

Velychko

³

2014

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The band spectrum of bosonic atoms in two-dimensional honeycomb optical lattices with the graphene-type structure has been studied. The dispersion laws in the bands and the one-particle spectral densities are calculated for the normal phase in the random phase approximation. The temperature-dependent gapless spectrum with Dirac points located at the Brillouin zone boundary is obtained for the lattice with energetically equivalent sites, with the corresponding chemical potential lying outside the allowed energy band. Different on-site energies in the sublattices are shown to induce the appearance of a gap in the spectrum, so that the chemical potential can be located between the subbands, which gives rise to a substantial reconstruction of the band spectrum. The frequency dependences of the one-particle spectral density for both sublattices are determined as functions of the chemical potential level, the spectral gap magnitude, and the temperature.K e y w o r d s: optical lattice, honeycomb lattice, phase transition, spectral density, hard-core bosons, Dirac points.

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“…This work continues our theoretical researches [21][22][23][24] dealing with the energy spectrum and the spectral characteristics of a quantum lattice Bose gas, and, in particular, the hard-core boson model. In the framework of the pseudospin approach, by applying the fermionization procedure in the one-dimensional case [21] and the random phase approximation in the more general three-dimensional one [22], modifications in the one-particle spectral densities at the transition from the non-ordered (NO) state into the ordered one, in which S x = b + = b = 0 and which is an analog of the phase with the lattice Bose condensate (the SF phase), were studied.…”

Section: Introductionsupporting

confidence: 57%

Investigation of the bosonic spectrum of two-dimensional optical graphene-type lattices. Normal phase

Stasyuk¹,

Dulepa²,

Velychko³

2014

Preprint

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The band spectrum of bosonic atoms in two-dimensional honeycomb optical lattices with the graphene-type structure has been studied. The dispersion laws in the bands and the one-particle spectral densities are calculated for the normal phase in the random phase approximation. The temperature-dependent gapless spectrum with Dirac points located at the Brillouin zone boundary is obtained for the lattice with energetically equivalent sites, with the corresponding chemical potential lying outside the allowed energy band. Different on-site energies in the sublattices are shown to induce the appearance of a gap in the spectrum, so that the chemical potential can be located between the subbands, which gives rise to a substantial reconstruction of the band spectrum. The frequency dependences of the one-particle spectral density for both sublattices are determined as functions of the chemical potential level, the spectral gap magnitude, and the temperature.

show abstract

Diagrams of State for One-Dimensional Hydrogen-Bonded Proton Conductor

Cited by 5 publications

References 26 publications

Energy spectrum and phase diagrams of two-sublattice hard-core boson model

Energy spectrum and phase diagrams of two-sublattice hard-core boson model

Investigation of the Bosonic Spectrum of Two-Dimensional Optical Graphene-Type Lattices. Normal Phase

Investigation of the bosonic spectrum of two-dimensional optical graphene-type lattices. Normal phase

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