International Journal of Modern Physics A

High Energy Spin Physics has made significant progress. During a very short period a set of new phenomena have been established — relevant to the spin structure of the nucleons, hyperon polarization, the single- and double-spin asymmetries. The recent advent of the polarized proton and antiproton beams, and unpolarized Σ ^- beam opened a new avenue for study of spin physics at high energy, like the flavor dependence of the spin effect, the spin transfer mechanism, the comparative study of the hyperon polarization and analyzing power, etc. These and other news in High Energy Spin Physics are discussed in this review.

We discuss continuous and discrete sectors in the collective field theory of D = 1 matrix models. A canonical Lorentz-invariant field theory extension of collective field theory is presented and its classical solutions in Euclidean and Minkowski space are found. We show that the discrete, low density sector of collective field theory includes single eigenvalue Euclidean instantons which tunnel between different vacua of the extended theory. We further show that these "stringy" instantons induce nonperturbative effective operators of strength in the extended theory. The relationship of the world sheet description of string theory and Liouville theory to the effective space–time theory is explained. We also comment on the role of the discrete, low density, sector of collective field theory in that framework.

We consider the quantum analogs of Euclidean wormholes obtained by Carlini and Mijić (CM), who analytically continued recollapsing closed universe models. Using a perfect fluid matter source, we obtain asymptotically Euclidean (AE) wormholes when the strong energy condition is satisfied. Such wormholes are found to be consistent with the Hawking–Page (HP) conjecture for quantum wormholes as solutions of the Wheeler–DeWitt (WDW) equation.

By simulating the equation of state of a perfect fluid with a real scalar field, quantum wormholes are also found when the strong energy condition is violated, although generally not AE. The non-AE solutions are interpreted as excited states of the quantum wormhole spectrum.

Our results give support to the claim of HP that quantum wormhole solutions are a fairly general property of the WDW equation for various matter sources. Matter sources giving quantum wormholes could now include those expected in low energy effective string theory: a dilaton scalar field with exponential potential. This is unlike the classical case where such matter sources do not allow wormhole solutions.

We finally contrast quantum wormhole solutions with other boundary conditions of quantum cosmology describing an inflationary earlier behavior and a resulting large Lorentzian universe phase.

A family of relativistic geometric models is defined as a generalization of the actual anti-de Sitter (1 + 1) model of the relativistic harmonic oscillator. It is shown that all these models lead to the usual harmonic oscillator in the nonrelativistic limit, even though their relativistic behavior is quite different. Among quantum models we find a set of models with countable energy spectra, and another one having only a finite number of energy levels and in addition a continuous spectrum.

We establish a weight-preserving bijection between the index sets of the spectral data of row-to-row and corner transfer matrices for restricted interaction round a face (IRF) models. The evaluation of momenta by adding Takahashi integers in the spin chain language is shown to directly correspond to the computation of the energy of a path on the weight lattice in the two-dimensional model. As a consequence we derive fermionic forms of polynomial analogs of branching functions for the cosets , and establish a bosonic–fermionic polynomial identity.

The Lagrangian of (1 + 1)-dimensional massive vector fields is studied. Since this system has second class constraints, the method of Batalin–Fradkin, which introduces new fields to convert second class constraints into first class ones, is applied in an extended manner. Instead of the usual treatment, which uses the Stueckelberg field as a new field, we can use a pseudoscalar field. We will show there are at least two ways to introduce a pseudoscalar. At the quantum level, one way leads to the system that is equivalent to the original system, and the other way gives an inequivalent system. The relation of these two ways is clarified. As an application of the latter way, we consider QCD at finite temperature and the gluonic effective action for hard thermal loops is constructed.

Quantizing the electromagnetic field with a group formalism faces the difficulty of how to turn the traditional gauge transformation of the vector potential, A_μ(x) → A_μ(x) + ∂_μ φ (x), into a group law. In this paper, it is shown that the problem can be solved by looking at gauge transformations in a slightly different manner which, in addition, does not require introducing any BRST-like parameter. This gauge transformation does not appear explicitly in the group law of the symmetry but rather as the trajectories associated with generalized equations of motion generated by vector fields with null Noether invariants. In the new approach the parameters of the local group, U(1)(x,t), acquire dynamical content outside the photon mass shell, a fact which also allows a unified quantization of both the electromagnetic and Proca fields.