11,525 research outputs found
Anisotropic power-law inflation for a conformal-violating Maxwell model
A set of power-law solutions of a conformal-violating Maxwell model with a
non-standard scalar-vector coupling will be shown in this paper. In particular,
we are interested in a coupling term of the form
with denoting the kinetic term of the scalar field. Stability analysis
indicates that the new set of anisotropic power-law solutions is unstable
during the inflationary phase. The result is consistent with the cosmic no-hair
conjecture. We show, however, that a set of stable slowly expanding solutions
does exist for a small range of parameters and . Hence a small
anisotropy can survive during the slowly expanding phase.Comment: 13 pages with 3 figure
Investigation of a universal behavior between N\'eel temperature and staggered magnetization density for a three-dimensional quantum antiferromagnet
We simulate the three-dimensional quantum Heisenberg model with a spatially
anisotropic ladder pattern using the first principles Monte Carlo method. Our
motivation is to investigate quantitatively the newly established universal
relation near the quantum critical
point (QCP) associated with dimerization. Here , , and are
the N\'eel temperature, the spinwave velocity, and the staggered magnetization
density, respectively. For all the physical quantities considered here, such as
and , our Monte Carlo results agree nicely with the
corresponding results determined by the series expansion method. In addition,
we find it is likely that the effect of a logarithmic correction, which should
be present in (3+1)-dimensions, to the relation
near the investigated QCP only sets in significantly in the region
with strong spatial anisotropy.Comment: 5 pages, 7 figures, 2 table
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