118604869
Backward running or absence of running from Creutz ratios
We extract the running coupling based on Creutz ratios in SU(2) lattice gauge theory with two Dirac fermions in the adjoint representation. Depending on how the extrapolation to zero fermion mass is performed, either backward running or an absence of running is observed at strong bare coupling. This behavior is consistent with other findings which indicate that this theory has an infrared fixed point.
118604869
Backward running or absence of running from Creutz ratios
We extract the running coupling based on Creutz ratios in SU(2) lattice gauge theory with two Dirac fermions in the adjoint representation. Depending on how the extrapolation to zero fermion mass is performed, either backward running or an absence of running is observed at strong bare coupling. This behavior is consistent with other findings which indicate that this theory has an infrared fixed point.
118624605
Finite size scaling in minimal walking technicolor
We compare observables to the finite size scaling hypothesis in SU(2) lattice gauge theory with two Dirac fermions in the adjoint representation. The fits that we obtain yield an estimate of the anomalous mass dimension that is consistent with four loop perturbation theory: $\gamma = 0.51 \pm 0.16$, with the error due to systematic uncertainties in the finite size scaling analysis. The result is somewhat larger than one Schr\"odinger functional study (by 1.3$\sigma$) but consistent with another.
119521416
Massive monopoles and massless monopole clouds
Magnetic monopole solutions naturally arise in the context of spontaneously broken gauge theories. When the unbroken symmetry includes a non-Abelian subgroup, investigation of the low-energy monopole dynamics by means of the moduli space approximation reveals degrees of freedom that can be attributed to massless monopoles. These do not correspond to distinct solitons, but instead are manifested as a cloud of non-Abelian field surrounding one or more massive monopoles. In these talks I explain how one is led to these solutions and then describe them in some detail.
15115663
Are all static black hole solutions spherically symmetric?
The static black hole solutions to the Einstein-Maxwell equations are all spherically symmetric, as are many of the recently discovered black hole solutions in theories of gravity coupled to other forms of matter. However, counterexamples demonstrating that static black holes need not be spherically symmetric exist in theories, such as the standard electroweak model, with electrically charged massive vector fields. In such theories, a magnetically charged Reissner-Nordström solution with sufficiently small horizon radius is unstable against the development of a nonzero vector field outside the horizon. General arguments show that, for generic values of the magnetic charge, this field cannot be spherically symmetric. Explicit construction of the solution shows that it in fact has no rotational symmetry at all.
13978988
Electromagnetic duality and SU(3) monopoles
Abstract We consider the low-energy dynamics of a pair of distinct fundamental monopoles that arise in the N = 4 supersymmetric SU (93) Yang-Mills theory broken to U (1) × U (1). Both the long distance interactions and the short distance behavior indicate that the moduli space is R 3 × (R 1 × M 0 ) Z where M 0 is the smooth Taub-NUT manifold, and we confirm this rigorously. By examining harmonic forms on the moduli space, we find a threshold bound state of two monopoles with a tower of BPS dyonic states built on it, as required by Montonen-Olive duality. We also present a conjecture for the metric of the moduli space for any number of distinct fundamental monopoles for an arbitrary gauge group.
118584534
Monopoles and the early universe
Grand unified theories predict the existence of superheavy magnetic monopoles. Combining these theories with standard big band cosmology appears to lead to the conclusion that an unacceptably large abundance of these would have been produced in the early universe. Several proposed mechanisms for suppressing the monopole abundance are reviewed.
123699278
Nonexistence of Spherically Symmetric Monopoles with Multiple Magnetic Charge
We show that in a spontaneously broken SU(2) gauge theory there are no field configurations with magnetic charge >1 which are both spherically symmetric and of finite energy. (AIP)