254 research outputs found
On Relativistic Brane Probes in Singular Spacetimes
We study the relativistic dynamics of brane probes in singular warped
spacetimes and establish limits for such analysis. The behavior of the
semiclassical brane probe wave functions implies that unitarity boundary
conditions can be imposed at the singularity.Comment: 9 pages, 1 figure, typos corrected and references adde
Exponential Hierarchy From Spacetime Variable String Vacua
It is shown that non-supersymmetric spacetime varying string vacua can lead
to an exponential hierarchy between the electroweak and the gravitational
scales. The hierarchy is naturally generated by a string coupling of O(1).Comment: 22 pages, Latex, 2 figure
Wave Functionals, Hamiltonians and Renormalization Group
We analyze the renormalization of wave functionals and energy eigenvalues in
field theory. A discussion of the structure of the renormalization group
equation for a general Hamiltonian system is also given.Comment: 14, CCNY-HEP 5/9
Probing Naked Singularities in Non-supersymmetric String Vacua
We present a detailed analysis of non-supersymmetric spacetime varying string
vacua which can lead to an exponential hierarchy between the electroweak and
the gravitational scales. In particular, we identify a limit in which these
vacua can be interpreted as supersymmetric vacua of F-theory. Furthermore, we
study the properties of these solutions as seen by -brane probes and
establish a non-supersymmetric analogue of the enhancon mechanism.Comment: 46 pages, Latex, 7 figures; the brane probe analysis (sections 3 and
4) has been revised, references added and typos correcte
Spin and Rotations in Galois Field Quantum Mechanics
We discuss the properties of Galois Field Quantum Mechanics constructed on a
vector space over the finite Galois field GF(q). In particular, we look at
2-level systems analogous to spin, and discuss how SO(3) rotations could be
embodied in such a system. We also consider two-particle `spin' correlations
and show that the Clauser-Horne-Shimony-Holt (CHSH) inequality is nonetheless
not violated in this model.Comment: 21 pages, 11 pdf figures, LaTeX. Uses iopart.cls. Revised
introduction. Additional reference
A Note on Effective Lagrangians in Matrix Theory
We study the relation between the effective Lagrangian in Matrix Theory and
eleven dimensional supergravity. In particular, we provide a relationship
between supergravity operators and the corresponding terms in the
post-Newtonian approximation of Matrix Theory.Comment: 7 pages, use harvmac. References adde
On the Nonperturbative Consistency of String Theory
An infinite number of distinct matrix models reproduce the perturbation
theory of string theory. Due to constraints of causality, however, we
argue that none of the existing constructions gives a consistent
nonperturbative definition of the string.Comment: 10 pages, 2 figures, LaTeX (author's name added
Spacetime Emergence and General Covariance Transmutation
Spacetime emergence refers to the notion that classical spacetime "emerges"
as an approximate macroscopic entity from a non-spatio-temporal structure
present in a more complete theory of interacting fundamental constituents. In
this article, we propose a novel mechanism involving the "soldering" of
internal and external spaces for the emergence of spacetime and the twin
transmutation of general covariance. In the context of string theory, this
mechanism points to a critical four dimensional spacetime background.Comment: 11 pages, v2: version to appear in MPL
Concomitant multiple anomalies of renal vessels and collecting system
Although anomalies of renal vessels and collecting system are relatively frequent, their concomitant occurrence is a rare event. During dissection of a 75-year-old male formalin-embalmed cadaver, we found multiple variations in the renal vessels and renal collecting system. Both kidneys were normal in size and anteriorly malrotated, with duplex collecting system and duplex ureter. One ureter drained the upper part of the kidney and the second ureter drained the lower part of the kidney. Superior and inferior collecting systems were separated by renal parenchyma. The right kidney had two renal arteries, the first renal artery (main renal artery) originating from the abdominal aorta, passing behind the inferior vena cava (IVC) and entering the kidney through the superior and inferior renal hilum. The second artery was the inferior polar artery. In addition, the right kidney had two renal veins as well. Three renal tributaries emerged from the upper and lower portion of the right renal hilum, and they joined to form the main renal vein which drained into the IVC. The lower renal vein was the inferior polar vein. The left kidney had four renal arteries (two hilar arteries and two polar arteries). The main left renal vein emerged from both superior and inferior left renal hilum, passed in front of the abdominal aorta and drained into the IVC. The left kidney also had the inferior polar vein which was divided behind the aorta (retro aortic vein) into two venous trunks. These venous trunks drained separately into posteromedialaspect of the IVC. Finally, the right testicular vein was formed by two tributaries and drained into the IVC, whereas the two left testicular veins drained separately into the left main renal vein
- …