2,333 research outputs found
A Non-renormalization Theorem for the Wilsonian Gauge Couplings in Supersymmetric Theories
We show that the holomorphic Wilsonian beta-function of a renormalizable
asymptotically free supersymmetric gauge theory with an arbitrary semi-simple
gauge group, matter content, and renormalizable superpotential is exhausted at
1-loop with no higher loops and no non-perturbative contributions. This is a
non-perturbative extension of the well known result of Shifman and Vainshtein.Comment: 10 pages, LaTeX; added references and clarified credit
Late Inflation and the Moduli Problem of Sub-Millimeter Dimensions
We consider a recent model with sub-millimeter sized extra dimensions, where
the field that determines the size of the extra dimensions (the radion) also
acts as an inflaton. The radion is also a stable modulus, and its coherent
oscillations can potentially overclose the Universe. It has been suggested that
a second round of late inflation can solve this problem, however we find that
this scenario does not allow for sufficient reheating of the Universe.Comment: 9 pages, LaTe
Minimum Length from First Principles
We show that no device or gedanken experiment is capable of measuring a
distance less than the Planck length. By "measuring a distance less than the
Planck length" we mean, technically, resolve the eigenvalues of the position
operator to within that accuracy. The only assumptions in our argument are
causality, the uncertainty principle from quantum mechanics and a dynamical
criteria for gravitational collapse from classical general relativity called
the hoop conjecture. The inability of any gedanken experiment to measure a
sub-Planckian distance suggests the existence of a minimal length.Comment: 8 pages, Honorable Mention in the 2005 Gravity Research Foundation
Essay Competitio
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