Erick J. Weinberg

Could the universe have recovered from a slow first-order phase transition?☆

We investigate the cosmological consequences of a phase transition which is driven primarily by slow nucleation of bubbles of the new phase via the effectively zero temperature quantum tunneling process of Coleman and Callan. These bubbles will asymptotically fill an arbitrarily large fraction of the space, yet they never percolate. Instead they form finite clusters, with each cluster dominated by a single largest bubble. The large scale thermalization required by the original “inflationary universe” scenario does not take place. The Coleman-De Luccia formalism for bubble formation in curved space is reviewed, with minor extensions. We argue that a single uncollided bubble would contain much less total entropy than the observed universe, unless the Higgs field potential involves widely disparate mass scales, as in the new inflationary universe scenario. We also argue that finite clusters are unlikely to yield a homogeneous and isotropic region containing sufficient entropy. Thus, unless the Higgs potential has the special form required by the new inflationary scenario, it appears quite implausible that there was such a phase transition in our past.

Magnetic monopole dynamics, supersymmetry, and duality

Abstract We review the properties of BPS, or supersymmetric, magnetic monopoles, with an emphasis on their low-energy dynamics and their classical and quantum bound states. After an overview of magnetic monopoles, we discuss the BPS limit and its relation to supersymmetry. We then discuss the properties and construction of multimonopole solutions with a single nontrivial Higgs field. The low-energy dynamics of these monopoles is most easily understood in terms of the moduli space and its metric. We describe in detail several known examples of these. This is then extended to cases where the unbroken gauge symmetry include a non-Abelian factor. We next turn to the generic supersymmetric Yang–Mills (SYM) case, in which several adjoint Higgs fields are present. Working first at the classical level, we describe the effects of these additional scalar fields on the monopole dynamics, and then include the contribution of the fermionic zero modes to the low-energy dynamics. The resulting low-energy effective theory is itself supersymmetric. We discuss the quantization of this theory and its quantum BPS states, which are typically composed of several loosely bound compact dyonic cores. We close with a discussion of the D-brane realization of N = 4 SYM monopoles and dyons and explain the ADHMN construction of monopoles from the D-brane point of view.

Black holes in magnetic monopoles

We study magnetically charged classical solutions of a spontaneously broken gauge theory interacting with gravity. We show that nonsingular monopole solutions exist only if the Higgs vacuum expectation value

Supersymmetry and self-dual Chern-Simons systems

v

Moduli space of many BPS monopoles for arbitrary gauge groups

is less than or equal to a critical value

Electromagnetic duality and SU(3) monopoles

v_{cr}

Fundamental Monopoles in Theories With Arbitrary Symmetry Breaking

, which is of the order of the Planck mass. In the limiting case the monopole becomes a black hole, with the region outside the horizon described by the critical Reissner-Nordstrom solution. For

Oscillating bounce solutions and vacuum tunneling in de Sitter spacetime

v<v_{cr}

Thermal derivation of the Coleman-De Luccia tunneling prescription

, we find additional solutions which are singular at

A classical instability of Reissner-Nordstrom solutions and the fate of magnetically charged black holes

r=0