122,243 research outputs found
Study of the ionic Peierls-Hubbard model using density matrix renormalization group methods
Density matrix renormalization group methods are used to investigate the
quantum phase diagram of a one-dimensional half-filled ionic Hubbard model with
bond-charge attraction, which can be mapped from the Su-Schrieffer-Heeger-type
electron-phonon coupling at the antiadiabatic limit. A bond order wave
(dimerized) phase which separates the band insulator from the Mott insulator
always exists as long as electron-phonon coupling is present. This is
qualitatively different from that at the adiabatic limit. Our results indicate
that electron-electron interaction, ionic potential and quantum phonon
fluctuations combine in the formation of the bond-order wave phase
Transmission of Water Waves under Multiple Vertical Thin Plates
The transmission of water waves under vertical thin plates, e.g., offshore floating breakwaters, oscillating water column wave energy converters, and so on, is a crucial feature that dominates the hydrodynamic performance of marine devices. In this paper, the analytical solution to the transmission of water waves under multiple 2D vertical thin plates is firstly derived based on the linear potential theory. The influences of relevant parameters on the wave transmission are discussed, which include the number of plates, the draft of plates, the distance between plates and the water depth. The analytical results suggest that the transmission of progressive waves gradually weakens with the growth of the number and draft of plates, and under the conditions of given number and draft of plates, the distribution of plates has significant influence on the transmission of progressive waves. The results of this paper contribute to the understanding of the transmission of water waves under multiple vertical thin plates, as well as the suggestion on optimal design of complex marine devices, such as a floating breakwater with multiple plates
Efficient Scheme for Perfect Collective Einstein-Podolsky-Rosen Steering
A practical scheme for the demonstration of perfect one-sided
device-independent quantum secret sharing is proposed. The scheme involves a
three-mode optomechanical system in which a pair of independent cavity modes is
driven by short laser pulses and interact with a movable mirror. We demonstrate
that by tuning the laser frequency to the blue (anti-Stokes) sideband of the
average frequency of the cavity modes, the modes become mutually coherent and
then may collectively steer the mirror mode to a perfect
Einstein-Podolsky-Rosen state. The scheme is shown to be experimentally
feasible, it is robust against the frequency difference between the modes,
mechanical thermal noise and damping, and coupling strengths of the cavity
modes to the mirror.Comment: 9 pages, 4 figure
General covariant geometric momentum, gauge potential and a Dirac fermion on a two-dimensional sphere
For a particle that is constrained on an ()-dimensional ()
curved surface, the Cartesian components of its momentum in -dimensional
flat space is believed to offer a proper form of momentum for the particle on
the surface, which is called the geometric momentum as it depends on the mean
curvature. Once the momentum is made general covariance, the spin connection
part can be interpreted as a gauge potential. The present study consists in two
parts, the first is a discussion of the general framework for the general
covariant geometric momentum. The second is devoted to a study of a Dirac
fermion on a two-dimensional sphere and we show that there is the generalized
total angular momentum whose three cartesian components form the
algebra, obtained before by consideration of dynamics of the particle, and we
demonstrate that there is no curvature-induced geometric potential for the
fermion.Comment: 8 pages, no figure. Presentation improve
On the nature of the lightest scalar resonances
We briefly review the recent progresses in the new unitarization approach
being developed by us. Especially we discuss the large
scatterings by making use of the partial wave matrix parametrization form.
We find that the pole may move to the negative real axis on the second
sheet of the complex plane, therefore it raises the interesting question
that this `' pole may be related to the in the linear
model.Comment: Talk presented by Zheng at ``Quark Confinement and Hadron
Spectroscopy VI'', 21--25 Sept. 2004, Cagliari, Italy. 3 pages with 2 figure
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