We consider three mechanisms of hysteresis phenomena in alternating magnetic field: the domain-wall motion in a random medium, the nucleation, and the retardation of magnetization due to slow ~critical! fluctuations. We construct a quantitative theory for all these processes. The hysteresis is characterized by two dynamic threshold fields, a coercive field and the so-called reversal field. Thei...

A dimensionally continued background-field method makes the rationality of the 4-loop quenched QED beta function far more reasonable than had previously appeared. After 33 years of quest, dating from Rosner’s discovery of 3-loop rationality, one finally sees cancellation of zeta values by the trace structure of individual diagrams. At 4-loops, diagram-by-diagram cancellation of ζ(5) does not ev...

In this paper we compare the performance of various automated theorem provers on nearly all of the theorems in loop theory known to have been obtained with the assistance of automated theorem provers. Our analysis yields some surprising results, e.g., the theorem prover most often used by loop theorists doesn’t necessarily yield the best performance.

We show that the expectation value of a circular BPS-Wilson loop in N = 4 SUSYM can be calculated exactly, to all orders in a 1/N expansion and to all orders in g2N . Using the AdS/CFT duality, this result yields a prediction of the value of the string amplitude with a circular boundary to all orders in α′ and to all orders in gs. We then compare this result with string theory. We find that the...

The one-loop effective action in φ 4 theory coupled non-linearly with curvature power and dynamical origin of cosmological constant Abstract. The functional formulation and one-loop effective action for scalar self-interacting theory non-linearly coupled with some power of the curvature are studied. After the explicit one-loop renormalization at weak curvature, we investigated numerically the p...