Intersections forms and the geometry of lattice Chern-Simons theory

We show that it is possible to formulate Abelian Chern-Simons theory on a lattice as a topological field theory. We discuss the relationship between gauge invariance of the Chern-Simons lattice action and the topological interpretation of the canonical structure. We show that these theories are exactly solvable and have the same degrees of freedom as the analogous continuum theories.Comment: 14 page

Self-Duality in Nonlinear Electromagnetism

We discuss duality invariant interactions between electromagnetic fields and matter. The case of scalar fields is treated in some detail.Comment: 10 pages, full postscript also available from http://theor1.lbl.gov/www/theorygroup/papers/40770.p

Solitons on Branes

We examine the possibility that gauge field configurations on stacks of parallel Dp branes support topological solitons. We give an exhaustive list of possible soliton charges for p<7. We also discuss how configurations carrying the soliton charges can be constructed from intersecting branes.Comment: 15 pages, 2 figures; v2: two references added, version to be published in Nucl.Phys.

Supergravity Solutions for BI Dyons

We construct partially localized supergravity counterpart solutions to the 1/2 supersymmetric non-threshold and the 1/4 supersymmetric threshold bound state BI dyons in the D3-brane Dirac-Born-Infeld theory. Such supergravity solutions have all the parameters of the BI dyons. By applying the IIA/IIB T-duality transformations to these supergravity solutions, we obtain the supergravity counterpart solutions to 1/2 and 1/4 supersymmetric BIons carrying electric and magnetic charges of the worldvolume U(1) gauge field in the Dirac-Born-Infeld theory in other dimensions.Comment: 17 pages, REVTeX, revised version to appear in Phys. Rev.

Smooth vortex precession in superfluid 4He

We have measured a precessing superfluid vortex line, stretched from a wire to the wall of a cylindrical cell. By contrast to previous experiments with a similar geometry, the motion along the wall is smooth. The key difference is probably that our wire is substantially off center. We verify several numerical predictions about the motion, including an asymmetry in the precession signature, the behavior of pinning events, and the temperature dependence of the precession.Comment: 8 pages, 8 figure

Non-BPS Dyons and Branes in the Dirac-Born-Infeld Theory

Non-BPS dyon solutions to D3-brane actions are constructed when one or more scalar fields describing transverse fluctuations of the brane, are considered. The picture emerging from such non-BPS configurations is analysed, in particular the response of the D-brane-string system to small perturbations.Comment: 16 pages, 4 figures, Revtex fil

Depinning of a superfluid vortex line by Kelvin waves

We measure the interaction of a single superfluid vortex with surface irregularities. While vortex pinning in superconductors usually becomes weaker at higher temperatures, we find the opposite behavior. The pinning steadily increases throughout our measurement range, from 0.15Tc to over 0.5Tc. We also find that moving the other end of the vortex decreases the pinning, so we propose Kelvin waves along the vortex as a depinning mechanism.Comment: 5 figures; substantial revision including 2 new figure

BLACK HOLE MULTIPLETS AND SPONTANEOUS BREAKING OF LOCAL SUPERSYMMETRY

We classify states saturating a double or a single supersymmetric positivity bound of a four-dimensional N=4 supersymmetry. The massive four-dimensional double-bound states (Bogomolny states) are shown to form a light-like representation of ten-dimensional supersymmetry. The single-bound states form a massive representation (centrino multiplet) of a four-dimensional supersymmetry. The first component of the centrino multiplet is identified with extreme black holes with regular horizon which have one quarter of unbroken supersymmetry. The centrino multiplet includes a massive spin 3/2 state, the centrino, as a highest spin state. Existence of massive black hole supermultiplets may affect the massless sector of the theory. Assuming that gluino condensate is formed one can study its properties. The bilinear combination of covariantly constant Killing spinors supplies the possible form for a gluino condensate. The condensate has null properties, does not introduce a cosmological constant, and may lead to a spontaneous breaking of local supersymmetry. This suggests that centrino may provide a consistent super-Higgs mechanism.Comment: 15 pages, LaTe

The Nonperturbative Color Meissner Effect in a Two-Flavor Color Superconductor

Color superconductivity in QCD breaks the SU(3) color gauge group down to SU(2), inducing masses in five of the eight gluons. This is a dynamical Higgs effect, in which the diquark condensate acts as the vacuum expectation value of a composite scalar field. In order to analyze this effect at low quark density, when gaps are large and generated nonperturbatively, we use instanton-induced quark interactions augmented with gauge-invariant interactions between quarks and perturbative gluons. The five gluon masses are found from the static limit of the relevant polarization operators, in which transversality is maintained via the Nambu-Goldstone modes of broken color symmetry. Working in the microscopic theory we calculate these masses to one-loop order and estimate their density dependence. Finally, we speculate that the Meissner effect may postpone the onset of color superconductivity to higher matter density than estimated previously.Comment: 27 pages, 7 figures, uses epsf.sty; typos corrected in Eqs. (38

Exotic torus manifolds and equivariant smooth structures on quasitoric manifolds

In 2006 Masuda and Suh asked if two compact non-singular toric varieties having isomorphic cohomology rings are homeomorphic. In the first part of this paper we discuss this question for topological generalizations of toric varieties, so-called torus manifolds. For example we show that there are homotopy equivalent torus manifolds which are not homeomorphic. Moreover, we characterize those groups which appear as the fundamental groups of locally standard torus manifolds. In the second part we give a classification of quasitoric manifolds and certain six-dimensional torus manifolds up to equivariant diffeomorphism. In the third part we enumerate the number of conjugacy classes of tori in the diffeomorphism group of torus manifolds. For torus manifolds of dimension greater than six there are always infinitely many conjugacy classes. We give examples which show that this does not hold for six-dimensional torus manifolds.Comment: 21 pages, 2 figures, results about quasitoric manifolds adde