No abstract available

[en] We employ conformal mapping techniques to obtain the oscillator representation of the three open string vertex in Witten's formulation of String Field Theory. We argue that the physical state couplings are identical to those of the dual resonance model, and we confirm this for the low lying states with our explicit construction

[en] An improved magnet which more easily provides a radially increasing magnetic field, as well as reduced fringe field and requires less power for a given field intensity. The subject invention comprises a pair of spaced, opposed magnetic poles which further comprise a pair of pole roots, each having a pole tip attached to its center. The pole tips define the gap between the magnetic poles and at least a portion of each pole tip is separated from its associated pole root. The separation begins at a predetermined distance from the center of the pole root and increases with increasing radial distance while being constant with azimuth within that portion. Magnets in accordance with the subject invention have been found to be particularly advantageous for use in large isochronous cyclotrons

[en] A general family of two-dimensional field theories of the Liouville type, involving one or more scalar fields, is shown to be conformally invariant when quantized canonically over a large class of Fock spaces

[en] The classical Baecklund transformation, which maps the Liouville model onto a free theory, is developed into an explicit operator relation for quantum fields. Conformal transformation properties and canonical commutation relations are preserved by this operator mapping. (orig.)

[en] Exact, closed form results are given expressing the quantum Liouville field theory in terms of a canonical free pseudoscalar field. The classical conformal transformation properties and Baechlund transformation of the Liouville model are briefly reviewed and then developed into explicit operator statements for the quantum theory. This development leads to exact expressions for the basic operator functions of the Liouville field: partial/sub μ/Phi, and e/sup n/phi. An operator product analysis is then used to construct the Liouville energy-momentum tensor operator, which is shown to be equal to that of a free pseudoscalar field. Dynamical consequences of this equilvalence are discussed, including the relation between the Liouville and free field energy eigenstates. Liouville correlation functions are partially analyzed, and remaining open questions are discussed

[en] Two independent weak-coupling expansions are developed for the Liouville quantum field theory in a circle. In the first, the coupling of the nonzero modes is treated as a perturbation on the exact solution to the zero-mode problem (quantum mechanics with an exponential potential). The second approach is a weak coupling approximation to an explicit operator solution which expresses various Liouville operators as functions of a free massless field using a Baecklund transformation. It is shown that the free state space associated with the latter solution must be restricted to the sector which is odd with respect to a type of ''parity.'' Various matrix elements are computed to order g¹⁰ using both approaches, yielding identical results

[en] A general family of two-dimensional field theories of the Liouville type, involving one or more scalar fields, is shown to be conformally invariant when quantized canonically over a large class of Fock spaces. (orig.)

[en] We study quantum chromodynamics in the limit of an infinite number of colors, N/sub c/, at fixed coupling, g/sub s/. On a null-plane lattice, the field theory can be recast as an interacting string model. The resulting dual string has internal degrees of freedom corresponding to the spin of the gluon quanta. The dynamics of these spins is that of an isotropic Heisenberg antiferromagnet. In the limit N/sub c/ → infinity, low orders in the dual loop expansion are expected to give a good approximation to the spectrum (modulo effects such as spontaneous symmetry breakdown). We find that, in this limit, all particles lie on linear Regge trajectories. Quarkless gluonic states correspond to closed strings, and the spectrum is Lorentz invariant if the intercept of the leading trajectory is two. Open strings are terminated by a quark and an antiquark, and the rho trajectory must have intercept unity. Our limit preserves chiral symmetry: There is a J/sup P/C = 0/sup (/+ scalar degenerate with the ''pion'' 0^-+. Both these particles are tachyons, so chiral symmetry may be spontaneously broken by string interactions. Our N/sub c/ → infinity calculations are similar to zero-temperature expansions in statistical mechanics. We expect them to give a qualitatively correct description of the ordered phase (confined quarks). We suggest that there is a critical number of colors below which confinement is lost. If N/sub c/ = 3 is close to this critical value (hopefully above it), the 1/N/sub c/ expansion might not give quantitatively accurate results

[en] A systematic weak-coupling expansion is developed for the Liouville quantum field theory on a periodic spatial interval. Matrix elements of various Liouville operators are computed to order g₈ by perturbation in nonzero modes about the exact solution of the zero-mode problem. To this order the results agree with the explicit operator solution given previously by Braaten, Curtright, and Thorn, in which the Liouville field was expressed in terms of a free pseudoscalar field by means of an operator Baaumlcklund transformation