2,207 research outputs found
Media used for culture of and distribution of stocks
Media used for culture of and distribution of stock
Preservation of amycelial-aconidial Neurospora cultures using anhydrous silica gel
Preservation of amycelial-aconidial Neurospora cultures using anhydrous silica ge
Preservation of Neurospora stock cultures with anhydrous silica gel
Preservation of Neurospora stock cultures with anhydrous silica ge
A method for scoring [mi-1] and [mi-1]f in growth tubes
Scoring [mi-1] and [mi-1]f in growth tube
Effect of nitrogen source and pH on the growth of a glutamine requiring strain (glm)
Effect of nitrogen source and pH on the growth of a glutamine requiring strain (glm
Growth conditions for [abn-1] and [abn-2] in liquid media
Growth conditions for [abn-1] and [abn-2] in liquid medi
Alternative formalism to the slave particle mean field theory of the t-J model without deconfinement
An alternative formalism that does not require the assumption of the
deconfinement phase of a U(1) gauge field is proposed for the slave particle
mean field theory. Starting form the spin-fermion model, a spinon field, which
is either fermion or boson, is introduced to represent the localized spin
moment. We find a d-wave superconductive state in the mean field theory in the
case of the fermion representation of the localized spin moment that
corresponds to the slave boson mean field theory of the t-J model, whereas the
d-wave superconductive state is absent in case of the Schwinger boson
representation of the localized spin moments.Comment: 8 page
Is there spin-charge separation in the 2D Hubbard and t-J models at low electronic densities?
The spin and density correlation functions of the two-dimensional Hubbard
model at low electronic density are calculated in the ground state by
using the power method, and at finite temperatures by using the quantum Monte
Carlo technique. Both approaches produce similar results, which are in close
agreement with numerical and high temperature expansion results for the
two-dimensional model. Using perturbative approximations, we show
that the examination of the density correlation function alone is not enough to
support recent claims in the literature that suggested spin and charge
separation in the low electronic density regime of the model.Comment: 11 pages, tex, 3 figures upon request, NTHU - preprin
Effect of the Three-Site Hopping Term on the t-J Model
We have used exact diagonalization and quantum Monte Carlo methods to study
the one-dimensional {t-J} model including the three-site hopping term derived
from the strong coupling limit of the Hubbard model. The three-site term may be
important to superconducting correlations since it allows direct hopping of
local singlet electron pairs. The phase diagram is determined for several
values of the strength of the three-site term and compared with that of the
{t-J} and Hubbard models. Phase separation, which exists in the t-J model is
suppressed. In the low electron density region the formation of local singlet
electron pairs is enhanced, leading to stronger superconducting correlations
even for values . A large spin gap region extends from low electron
densities up to high densities. In the low hole density region the
superconducting correlations are suppressed at in spite of enhanced
pair formation. This is because the three-site term, while enhancing the
formation of electron pairs, leads to a repulsion between holes.Comment: 9 pages including 9 figures and 1 Table. Self-unpacking postscript.
Unpacking instructions are at the beginning of the file. Submitted to
Physical Review
Variational state based on the Bethe ansatz solution and a correlated singlet liquid state in the one-dimensional t-J model
The one-dimensional t-J model is investigated by the variational Monte Carlo
method. A variational wave function based on the Bethe ansatz solution is newly
proposed, where the spin-charge separation is realized, and a long-range
correlation factor of Jastrow-type is included. In most regions of the phase
diagram, this wave function provides an excellent description of the
ground-state properties characterized as a Tomonaga-Luttinger liquid; Both of
the amplitude and exponent of correlation functions are correctly reproduced.
For the spin-gap phase, another trial state of correlated singlet pairs with a
Jastrow factor is introduced. This wave function shows generalized Luther-Emery
liquid behavior, exhibiting enhanced superconducting correlations and
exponential decay of the spin correlation function. Using these two variational
wave functions, the whole phase diagram is determined. In addition, relations
between the correlation exponent and variational parameters in the trial
functions are derived.Comment: REVTeX 3.0, 27 pages. 7 figures available upon request
([email protected]). To be published in Phys. Rev. B 5
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