946 research outputs found
Crystalline chiral condensates off the tricritical point in a generalized Ginzburg-Landau approach
We present an extensive study on inhomogeneous chiral condensates in QCD at
finite density in the chiral limit using a generalized Ginzburg-Landau (GL)
approach. Performing analyses on higher harmonics of one-dimensionally (1D)
modulated condensates, we numerically confirm the previous claim that the
solitonic chiral condensate characterized by Jacobi's elliptic function is the
most favorable structure in 1D modulations. We then investigate the possibility
of realization of several multidimensional modulations within the same
framework. We also study the phase structure far away from the tricritical
point by extending the GL functional expanded up to the eighth order in the
order parameter and its spatial derivative. On the same basis, we explore a new
regime in the extended GL parameter space and find that the Lifshitz point is
the point where five critical lines meet at once. In particular, the existence
of an intriguing triple point is demonstrated, and its trajectory consists of
one of those critical lines.Comment: 17 pages, 20 eps figures; (v2) corrected an error in computation of
eighth order coefficients; (v3) typos corrected, version to appear in Phys.
Rev.
Notes on projective structures and Kleinian groups
Throughout this paper, C will denote the complex plane, C ̂ = C ∪ {∞} the number sphere, and D = {z: |z | < 1} ⊂ C the unit disk. We use PSL(2,C) = SL(2,C) / ± id for the group of Möbius transformations of Ĉ. With Γ an arbitrary Fuchsian group, possibly having elliptic elements, let
Predict-prevent control method for perturbed excitable systems
We present a control method based on two steps: prediction and prevention.
For prediction we use the anticipated synchronization scheme, considering
unidirectional coupling between excitable systems in a master-slave
configuration. The master is the perturbed system to be controlled, meanwhile
the slave is an auxiliary system which is used to predict the master's
behavior. We demonstrate theoretically and experimentally that an efficient
control may be achieved.Comment: 4 pages, 5 figure
Dilatancy Behavior in Constant Strain Rate Consolidation Test
. Although the constant strain rate consolidation (CSRC) test appears to be one of the most promising types of rapid consolidation test, the time dependency in stress-strain response such as the secondary compression has not been sufficiently clarified yet in CSRC test. Subjected to remolded young clay, this paper shows that a lot of time dependent behavior in the standard consolidation (SC) and CSRC tests is represented systematically by a simple assumption concerning the time dependency of dilatancy. In the SC test, at the first stage of each loading step little dilatancy takes place and dilatancy begins to occur several minutes after step loading. At the latter of each loading step, dilatancy occurs proportionally with the logarithm of elapsed time, which is observed as the secondary compression. In CSRC test, some time period after the stress state has entered the normally consolidated region, dilatancy tends to occur rapidly with the increase in stress ratio. Since most of dilatancy has taken place at the earlier stage of consolidation, little dilatancy occurs at the latter stage of CSRC process. This tendency makes the specimen stiffer with the passage of time, and makes the vertical pressure and pore pressure increase substantially at the last stage of CSRC process. Consideration to such behavior may be effective to correctly interpret the result of CSRC test
High Ratio of 44Ti/56Ni in Cas A and Axisymmetric Collapse-Driven Supernova Explosion
The large abundance ratio of in Cas A is puzzling. In fact,
the ratio seems to be larger than the theoretical constraint derived by Woosley
& Hoffman (1991). However, this constraint is obtained on the assumption that
the explosion is spherically symmetric, whereas Cas A is famous for the
asymmetric form of the remnant. Recently, Nagataki et al. (1997) calculated the
explosive nucleosynthesis of axisymmetrically deformed collapse-driven
supernova. They reported that the ratio of was enhanced by
the stronger alpha-rich freezeout in the polar region. In this paper, we apply
these results to Cas A and examine whether this effect can explain the large
amount of and the large ratio of . We demonstrate
that the conventional spherically symmetric explosion model can not explain the
Ti mass produced in Cas A if its lifetime is shorter than 80
years and the intervening space is transparent to the gamma-ray line from the
decay of Ti. On the other hand, we show the axisymmetric explosion
models can solve the problem. We expect the same effect from a three
dimensionally asymmetric explosion, since the stronger alpha-rich freezeout
will also occur in that case in the region where the larger energy is
deposited.Comment: 10 pages, LaTeX text and 3 postscript figure
Structural basis for rifamycin resistance of bacterial RNA polymerase by the three most clinically important RpoB mutations found in Mycobacterium tuberculosis
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/136512/1/mmi13606.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/136512/2/mmi13606_am.pd
Evolution Equation of Phenotype Distribution: General Formulation and Application to Error Catastrophe
An equation describing the evolution of phenotypic distribution is derived
using methods developed in statistical physics. The equation is solved by using
the singular perturbation method, and assuming that the number of bases in the
genetic sequence is large. Applying the equation to the mutation-selection
model by Eigen provides the critical mutation rate for the error catastrophe.
Phenotypic fluctuation of clones (individuals sharing the same gene) is
introduced into this evolution equation. With this formalism, it is found that
the critical mutation rate is sometimes increased by the phenotypic
fluctuations, i.e., noise can enhance robustness of a fitted state to mutation.
Our formalism is systematic and general, while approximations to derive more
tractable evolution equations are also discussed.Comment: 22 pages, 2 figure
Explosive Nucleosynthesis in Axisymmetrically Deformed Type II Supernovae
Explosive nucleosynthesis under the axisymmetric explosion in Type II
supernova has been performed by means of two dimensional hydrodynamical
calculations. We have compared the results with the observations of SN 1987A.
Our chief findings are as follows: (1) is synthesized so much as to
explain the tail of the bolometric light curve of SN 1987A. We think this is
because the alpha-rich freezeout takes place more actively under the
axisymmetric explosion. (2) and tend to be overproduced
compared with the observations. However, this tendency relies strongly on the
progenitor's model.
We have also compared the abundance of each element in the mass number range
with the solar values. We have found three outstanding features. (1)
For the nuclei in the range , their abundances are insensitive to the
initial form of the shock wave. This insensitivity is favored since the
spherical calculations thus far can explain the solar system abundances in this
mass range. (2) There is an enhancement around A=45 in the axisymmetric
explosion compared with the spherical explosion fairly well. In particular,
, which is underproduced in the present spherical calculations, is
enhanced significantly. (3) In addition, there is an enhancement around A=65.
This tendency does not rely on the form of the mass cut but of the initial
shock wave. This enhancement may be the problem of the overproduction in this
mass range, although this effect would be relatively small since Type I
supernovae are chiefly responsible for this mass number range.Comment: 32 pages, 12 figures, LaTe
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