نتایج جستجو برای: constant composition expansion
تعداد نتایج: 604094 فیلتر نتایج به سال:
The phase structure of Nambu-Jona-Lasinio model with N-component fermions in curved space-time is studied in the leading order of the 1/N expansion. The effective potential for composite operator ¯ ψψ is calculated by using the normal coordinate expansion in the Schwinger proper-time method. The existence of the first-order phase transition caused by the change of the space-time curvature is co...
The strict coupling constant expansion for the free energy of hot QCD plasma shows bad convergence at all reasonable temperatures, and does not agree well with its 4D lattice determination. This has recently led to various refined resummations, whereby the agreement with the lattice result should improve, at the cost of a loss of a formal agreement with the coupling constant expansion and parti...
The sizes of optimal constant-composition codes of weight three have been determined by Chee, Ge and Ling with four cases in doubt. Group divisible codes played an important role in their constructions. In this paper, we study the problem of constructing optimal ternary constant-composition codes with Hamming weight four and minimum distance six. The problem is solved with a small number of len...
We have used the locally self-consistent Green’s function (LSGF) method in supercell calculations to establish the distribution of the net charges assigned to the atomic spheres of the alloy components in metallic alloys with different compositions and degrees of order. This allows us to determine the Madelung potential energy of a random alloy in the single-site mean field approximation which ...
Data from 10 unlinked autosomal noncoding regions, resequenced in 15 individuals from each of three populations, were used in a multilocus analysis to test models of human demography. Each of the 10 regions consisted of approximately 2500 bp. The multilocus analysis, based on summary statistics (average and variance of Tajima's D and Fu and Li's D*), was used to test a family of models with rec...
The Rayleigh-Schrr odinger perturbation series for the energy eigenvalue of an anharmonic oscillator deened by the Hamiltonian ^ H (m) () = ^ p 2 + ^ x 2 + ^ x 2m with m = 2; 3; 4;. .. diverges quite strongly for every 6 = 0 and has to summed to produce numerically useful results. However, a divergent weak coupling expansion of that kind cannot be summed eeectively if the coupling constant is l...
We consider the problem of testing graph expansion in the bounded degree model. We give a property tester that given a graph with degree bound d, an expansion bound α, and a parameter ε > 0, accepts the graph with high probability if its expansion is more than α, and rejects it with high probability if it is ε-far from any graph (with degree bound 2d) with expansion Ω(α). The algorithm runs in ...
Laminar mixed convection of Aluminium oxide (Al2O3)–water nanofluid flow in an inclined annulus using a single-phase approach was numerically studied. Constant heat flux boundary conditions were applied on the inner and outer walls. All the thermophysical properties of nanofluid, such as, viscosity, heat capacity, thermal conductivity, and thermal expansion coefficient...
Recently, there has been suggestions that the apparent accelerated expansion of the universe is due not to a cosmological constant, but rather to inhomogeneities in the distribution of matter. In this work, we investigate a specific class of inhomogeneous models that can be solved analytically, namely the dust-dominated Lemâitre-Tolman-Bondi universe models. We show that they do not permit acce...
ar X iv : h ep - t h / 04 10 07 1 v 1 7 O ct 2 00 4 DIVERGENCE OF THE 1 N f - SERIES EXPASION IN QED
It has been argued by Dyson that the perturbation theory in coupling constant in QED can not be convergent. We provide similar arguments for the divergence of the series of 1 Nf expansion in QED. This result should hold for large class of QFTs where such an expansion is under taken. PACS numbers:03.65.-w,11.01.-z,12.20.-m
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