No abstract available

[en] Two independent methods are employed to deduce the multiplet structure of a higher spin superspace. The first is based on the usual theta expansion. A general diagrammatic method is developed for working out the various components of the superfield. The case of the superfield with a vector spinor SUSY coordinate is worked out in detail. The second approach utilizes the Winger method of induced representations. The two approaches are shown to give analogous results for the representations. 6 refs. (author)

[en] Equations resulting from the unitarity of the collision matrix are investigated in standard resonance theory. The nonuniqueness or otherwise of fitted resonance parameters is discussed. (author)

[en] We use the Bethe–Peierls method combined with the belief propagation algorithm to study the arctic curves in the six vertex model on a square lattice with domain-wall boundary conditions, and the six vertex model on a rectangular lattice with partial domain-wall boundary conditions. We show that this rather simple approximation yields results that are remarkably close to the exact ones when these are known, and allows one to estimate the location of the phase boundaries with relative little effort in cases in which exact results are not available. (paper)

[en] The spin-Peierls phase transition has been studied in present article. In order to reveal the role of nonlinear classical excitations the quantum antiferromagnetic has been investigated.

[en] The Peierls-Bogolyubov inequality was generalized and a set of inequalities was derived instead, so that every subsequent inequality in this set approximates the quality in question with better precision than the preceding one. These inequalities lead to a sequence of improving upper bounds to the free energy of a quantum system if this system allows representation in terms of coherent states

[en] A single hydrogen atom in the universe kept at temperature T cannot exist in a bound state. This constitutes a surprise according to Peierls because the ionization in an assembly of hydrogen atoms is finite. The behaviour of a single hydrogen atom is first considered on its own and then as a limiting case of an assembly of atoms. Since the partition sum for the bound part diverges, care is needed in the derivation of the ionization formula proposed by Saha. (author)

[en] We point out that Peierls substitution used by Estrera and Arnold [Phys. Rev. B 39, 2094 (1989)] leads to incorrect results for the eigenvalue to determine the angle dependence of the upper critical field

[en] A set of brackets for classical dissipative systems, subject to external random forces, are derived. The method is inspired by the old procedure found by Peierls, for deriving the canonical brackets of conservative systems, starting from an action principle. It is found that an adaptation of Peierls' method is applicable also to dissipative systems, when the friction term can be described by a linear functional of the coordinates, as is the case in the classical Langevin equation, with an arbitrary memory function. The general expression for the brackets satisfied by the coordinates, as well as by the external random forces, at different times, is determined, and it turns out that they all satisfy the Jacobi identity. Upon quantization, these classical brackets are found to coincide with the commutation rules for the quantum Langevin equation, that have been obtained in the past, by appealing to microscopic conservative quantum models for the friction mechanism

No abstract available