3,085 research outputs found
Asymmetric Cosets
The aim of this work is to present a general theory of coset models G/H in
which different left and right actions of H on G are gauged. Our main results
include a formula for their modular invariant partition function, the
construction of a large set of boundary states and a general description of the
corresponding brane geometries. The paper concludes with some explicit
applications to the base of the conifold and to the time-dependent Nappi-Witten
background.Comment: 34 pages, LaTeX, 8 figures, 1 table, v2: references added, v3: typos
correcte
The Stueckelberg Field
In 1938, Stueckelberg introduced a scalar field which makes an Abelian gauge
theory massive but preserves gauge invariance. The Stueckelberg mechanism is
the introduction of new fields to reveal a symmetry of a gauge--fixed theory.
We first review the Stueckelberg mechanism in the massive Abelian gauge theory.
We then extend this idea to the standard model, stueckelberging the
hypercharge U(1) and thus giving a mass to the physical photon. This introduces
an infrared regulator for the photon in the standard electroweak theory, along
with a modification of the weak mixing angle accompanied by a plethora of new
effects. Notably, neutrinos couple to the photon and charged leptons have also
a pseudo-vector coupling. Finally, we review the historical influence of
Stueckelberg's 1938 idea, which led to applications in many areas not
anticipated by the author, such as strings. We describe the numerous proposals
to generalize the Stueckelberg trick to the non-Abelian case with the aim to
find alternatives to the standard model. Nevertheless, the Higgs mechanism in
spontaneous symmetry breaking remains the only presently known way to give
masses to non-Abelian vector fields in a renormalizable and unitary theory.Comment: 58 pages, revtex4 RMP format. Added references, minor improvements to
tex
Escape Rates and Singular Limiting Distributions for Intermittent Maps with Holes
We study the escape dynamics in the presence of a hole of a standard family
of intermittent maps of the unit interval with neutral fixed point at the
origin (and finite absolutely continuous invariant measure). Provided that the
hole (is a cylinder that) does not contain any neighborhood of the origin, the
surviving volume is shown to decay at polynomial speed with time. The
associated polynomial escape rate depends on the density of the initial
distribution, more precisely, on its behavior in the vicinity of the origin.
Moreover, the associated normalized push forward measures are proved to
converge to the point mass supported at the origin, in sharp contrast to
systems with exponential escape rate. Finally, a similar result is obtained for
more general systems with subexponential escape rates; namely that the Ces\`aro
limit of normalized push forward measures is typically singular, invariant and
supported on the asymptotic survivor set.Comment: To appear in Trans. Amer. Math. So
Toric Geometry and String Theory Descriptions of Qudit Systems
In this paper, we propose a new way to approach qudit systems using toric
geometry and related topics including the local mirror symmetry used in the
string theory compactification. We refer to such systems as (n,d) quantum
systems where and denote the number of the qudits and the basis states
respectively. Concretely, we first relate the (n,d) quantum systems to the
holomorphic sections of line bundles on n dimensional projective spaces CP^{n}
with degree n(d-1). These sections are in one-to-one correspondence with d^n
integral points on a n-dimensional simplex. Then, we explore the local mirror
map in the toric geometry language to establish a linkage between the (n,d)
quantum systems and type II D-branes placed at singularities of local
Calabi-Yau manifolds. (1,d) and (2,d) are analyzed in some details and are
found to be related to the mirror of the ALE space with the A_{d-1} singularity
and a generalized conifold respectively.Comment: 12 pages,latex, 2 figures. Accepted for publication in Journal of
Geometry and Physics, JPS(2015
- …