22,404 research outputs found
Chiral perturbation theory with Wilson-type fermions including effects: degenerate case
We have derived the quark mass dependence of , and
, using the chiral perturbation theory which includes the effect
associated with the explicit chiral symmetry breaking of the Wilson-type
fermions, in the case of the degenerate quarks. Distinct features of
the results are (1) the additive renormalization for the mass parameter
in the Lagrangian, (2) corrections to the chiral log ()
term, (3) the existence of more singular term, , generated by
contributions, and (4) the existence of both and terms
in the quark mass from the axial Ward-Takahashi identity, . By
fitting the mass dependence of and , obtained by the
CP-PACS collaboration for full QCD simulations, we have found that the
data are consistently described by the derived formulae. Resumming the most
singular terms , we have also derived the modified formulae, which
show a better control over the next-to-leading order correction.Comment: 21 pages, 4 figures (10 eps files), Revtex4, some discussions and
references added, the final version to appear in PR
Two-dimensional Gross-Neveu Model with Wilson Fermion Action at Finite Temperature and Density
We analytically investigate the 2-dimensional Gross-Neveu model at finite
temperature and density using Wilson fermion action. The relation between the
phase structure on the lattice and that in the continuum is clarified.Comment: LATTICE98(hightemp), 3 pages, 3 eps figure
Two-dimensional Lattice Gross-Neveu Model with Wilson Fermion Action at Finite Temperature and Chemical Potential
We investigate the phase structure of the two-dimensional lattice Gross-Neveu
model formulated with the Wilson fermion action to leading order of 1/N
expansion. Structural change of the parity-broken phase under the influence of
finite temperature and chemical potential is studied. The connection between
the lattice phase structure and the chiral phase transition of the continuum
theory is clarified.Comment: 42 pages, 20 EPS figures, using REVTe
Isotropic and Anisotropic Lattice Spacing Corrections for I=2 pi-pi Scattering from Effective Field Theory
The calculation of the finite lattice spacing corrections for I=2 pi-pi
scattering is carried out for isotropic and anisotropic Wilson lattice actions.
Pion masses and decay constants are also determined in this context. These
results correct the phase shift calculated from the lattice, which is connected
to the scattering length and effective range in this low energy scattering
process. When in terms of the lattice-physical parameters for either Wilson
action, these lattice spacing effects first appear at the next-to-leading order
counter-terms.Comment: 15 pages, additional discussion of pion decay constant, version
published in PR
Oscillation Frequency Dependence of Non-Classical Rotation Inertia of Solid He
The non-classical rotational inertia fraction of the identical cylindrical
solid He below 300 mK is studied at 496 and 1173 Hz by a double resonance
torsional oscillator. Below 35 mK, the fraction is the same at sufficiently low
rim velocities. Above 35 mK, the fraction is greater for the higher than the
lower mode. The dissipation peak of the lower mode occurs at a temperature
4 mK lower than that of the higher mode. The drive dependence of the two
modes shows that the reduction of the fraction is characterized by critical
velocity, \textit{not} amplitude nor acceleration.Comment: 4 pages, 4 figure
Product Development and the Timing of Information Disclosure under U.S.and Japanese Patent Systems
This paper examines the consequences of the differences in the timing of information disclosure between the U.S. and Japanese patent systems. Under the Japanese system it is possible for a firm to apply for a patent knowing the exact specifications of a rival's patent application. In contrast, in the U.S. the only way a firm learns about a rival's innovation is upon the actual granting of the rival's patent. We argue that this difference enables Japanese firms to coordinate their R&D efforts better than their U.S. counterparts and that this, in turn, leads to smaller quality improvements under the Japanese system. We show that the creation/diffusion tradeoff of patents can be influenced not only by the scope and length of patent protection but also by other features of the patenting process.
Enhancement of field renormalization in scalar theories via functional renormalization group
The flow equations of the Functional Renormalization Group are applied to the
O(N)-symmetric scalar theory, for N=1 and N=4, in four Euclidean dimensions,
d=4, to determine the effective potential and the renormalization function of
the field in the broken phase. In our numerical analysis, the infrared limit,
corresponding to the vanishing of the running momentum scale in the equations,
is approached to obtain the physical values of the parameters by extrapolation.
In the N=4 theory a non-perturbatively large value of the physical
renormalization of the longitudinal component of the field is observed. The
dependence of the field renormalization on the UV cut-off and on the bare
coupling is also investigated.Comment: 20 pages, 7 figures. To appear in Physical Review
Markov bases and subbases for bounded contingency tables
In this paper we study the computation of Markov bases for contingency tables
whose cell entries have an upper bound. In general a Markov basis for unbounded
contingency table under a certain model differs from a Markov basis for bounded
tables. Rapallo, (2007) applied Lawrence lifting to compute a Markov basis for
contingency tables whose cell entries are bounded. However, in the process, one
has to compute the universal Gr\"obner basis of the ideal associated with the
design matrix for a model which is, in general, larger than any reduced
Gr\"obner basis. Thus, this is also infeasible in small- and medium-sized
problems. In this paper we focus on bounded two-way contingency tables under
independence model and show that if these bounds on cells are positive, i.e.,
they are not structural zeros, the set of basic moves of all
minors connects all tables with given margins. We end this paper with an open
problem that if we know the given margins are positive, we want to find the
necessary and sufficient condition on the set of structural zeros so that the
set of basic moves of all minors connects all incomplete
contingency tables with given margins.Comment: 22 pages. It will appear in the Annals of the Institution of
Statistical Mathematic
The Weakly Coupled Gross-Neveu Model with Wilson Fermions
The nature of the phase transition in the lattice Gross-Neveu model with
Wilson fermions is investigated using a new analytical technique. This involves
a new type of weak coupling expansion which focuses on the partition function
zeroes of the model. Its application to the single flavour Gross-Neveu model
yields a phase diagram whose structure is consistent with that predicted from a
saddle point approach. The existence of an Aoki phase is confirmed and its
width in the weakly coupled region is determined. Parity, rather than chiral
symmetry breaking naturally emerges as the driving mechanism for the phase
transition.Comment: 15 pages including 1 figur
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