Browsing by Author "Skagerstam, BS"

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    CANONICAL QUANTIZATION OF CHIRAL BOSONS
    (American Physical Society, 1989-04-17) Salomonson, P; Skagerstam, BS; Stern, A; University of Alabama Tuscaloosa
    We perform the canonical quantization for a system of non-Abelian chiral bosons. We show that unlike in the Wess-Zumino-Witten model, the left- and right-handed current densities do not simultaneously span Kac-Moody algebras in the quantum theory. At the critical values of the coupling constants, only one Kac-Moody algebra results. © 1989 The American Physical Society.
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    GAUGE-THEORY OF EXTENDED OBJECTS
    (American Physical Society, 1979-07-15) Balachandran, AP; Stern, A; Skagerstam, BS; European Organization for Nuclear Research (CERN); University of Texas System; University of Texas Austin; University of Alabama Tuscaloosa
    Equations of motion and the Lagrangian formalism for extended objects coupled to Abelian and non-Abelian gauge fields are developed. These equations are minimal generalizations of the corresponding equations for point particles. It is seen that the string superconducts when it couples to an Abelian gauge field. Further, in this case, (a) the total charge on it is quantized, and (b) the total magnetic flux through it is quantized and conserved if it is closed and no segment of it is electrically neutral. The Lagrangians which lead to the equations of motion are not unique. Here, for a suitable Lagrangian, property (a) emerges at the classical level, the total charge being a topological invariant which labels the elements of 1[U(1)]. Both of these properties partially generalize to other extended objects and non-Abelian gauge fields. It is pointed out that for some Lagrangians, extended objects may have topological invariants (the analogs of total charge) for any gauge group. Supersymmetric extensions of the interaction Lagrangians are also outlined. For a point particle, such an extension correctly describes a spin-half particle in an Abelian or a non-Abelian gauge field. © 1979 The American Physical Society.
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    SUPERCONDUCTING EXTENDED OBJECTS AND APPLICATIONS TO THE PHASE-STRUCTURE OF QUANTUM CHROMODYNAMICS
    (American Physical Society, 1982-03-15) Skagerstam, BS; Stern, A; European Organization for Nuclear Research (CERN); University of Texas System; University of Texas Austin; University of Alabama Tuscaloosa
    In a previous work the dynamics of relativistic extended objects (i.e., strings, shells, etc.) coupled to Abelian or non-Abelian gauge fields was developed. The extended objects possessed an electriclike current which was defined in the associated Lie algebra of the gauge group under consideration. In the present paper, the interaction between the extended objects and gauge fields is slightly modified so that the objects behave like superconductors. By this we mean (a) the electrical conductivity is infinite and (b) for objects other than strings, a magnetic shielding or Meissner effect (with zero penetration depth) is present. Both (a) and (b) are features which occur in the classical description of the system. We also develop the dynamics for a system which is dual to the one described above. That is, instead of possessing an electric current, the objects here carry a magnetic current (Abelian or non-Abelian). Furthermore, the magnetic conductivity is infinite, and for objects other than strings an electric shielding or "dual" Meissner effect is present. The systems developed here contain Dirac's extended electron model and the MIT bag model as special cases. The former coincides with the description of an electrically charged shell. In the latter, we verify that the dynamics of a cavity within a (magnetic) superconducting vacuum is identical to that of a glueball in the MIT bag. This agrees with the view that the true quantum-chromodynamic (QCD) vacuum may be in a magnetic superconducting phase, and that the "dual" Meissner effect may be relevant for the confinement question. We also examine the possibility of the QCD vacuum being in an electric (or conventional) superconducting phase and a mixed superconducting phase, and comment on the confinement question for these two cases. © 1982 The American Physical Society.