1,569 research outputs found
A New Mechanism of Spontaneous SUSY Breaking
We propose a new mechanism of spontaneous supersymmetry breaking. The
existence of extra dimensions with nontrivial topology plays an important role.
We investigate new features resulted from the mechanism in two simple
supersymmetric Z_2 and U(1) models. One of remarkable features is that there
exists a phase in which the translational invariance for the compactified
directions is broken spontaneously, accompanying the breakdown of the
supersymmetry. The mass spectrum of the models appeared in reduced dimensions
is a full of variety, reflecting the highly nontrivial vacuum structure of the
models. The Nambu-Goldstone bosons (fermions) associated with breakdown of
symmetries are found in the mass spectrum. Our mechanism also yields quite
different vacuum structures if models have different global symmetries.Comment: 43 pages, 3 figure
Leggett-Garg inequalities and the geometry of the cut polytope
The Bell and Leggett-Garg tests offer operational ways to demonstrate that
non-classical behavior manifests itself in quantum systems, and
experimentalists have implemented these protocols to show that classical
worldviews such as local realism and macrorealism are false, respectively.
Previous theoretical research has exposed important connections between more
general Bell inequalities and polyhedral combinatorics. We show here that
general Leggett-Garg inequalities are closely related to the cut polytope of
the complete graph, a geometric object well-studied in combinatorics. Building
on that connection, we offer a family of Leggett-Garg inequalities that are not
trivial combinations of the most basic Leggett-Garg inequalities. We then show
that violations of macrorealism can occur in surprising ways, by giving an
example of a quantum system that violates the new "pentagon" Leggett-Garg
inequality but does not violate any of the basic "triangle" Leggett-Garg
inequalities.Comment: 5 pages, 1 figur
An algorithm for a general class of routing problems derived from Huygens' principle
If a set of N points or nodes with a nonnegative cost associated with each ordered pair is known, it is desired to find a path from one given node to another given node which minimizes the cost sum. An algorithm is presented which yields a global minimum solution after at most N - 1 iterations or on a typical large third-generation computer, after 1 hour of computation time for a 10,000-node problem. The rapid-access data storage capacity demanded by the algorithm is approximately 3N words for costs read in from slow-access storage or 2N words for calculable costs. The time-storage requirements of the algorithm known to the authors. When the problem is viewed as a discretized optimal control problem, after N-1 iterations, an optimal control or node transition is established for each of the N nodes or states; thus, the algorithm can be applied to situations were there may be errors in the control that necessitate a closed loop control that necessitate a closed loop control philosophy
Alien Registration- Burpee, Avis M. (Exeter, Penobscot County)
https://digitalmaine.com/alien_docs/10006/thumbnail.jp
Bell inequalities from variable elimination methods
Tight Bell inequalities are facets of Pitowsky's correlation polytope and are
usually obtained from its extreme points by solving the hull problem. Here we
present an alternative method based on a combination of algebraic results on
extensions of measures and variable elimination methods, e.g., the
Fourier-Motzkin method. Our method is shown to overcome some of the
computational difficulties associated with the hull problem in some non-trivial
cases. Moreover, it provides an explanation for the arising of only a finite
number of families of Bell inequalities in measurement scenarios where one
experimenter can choose between an arbitrary number of different measurements
ATM-CMG control system stability
Stability analyses and simulation data and results are presented for an initial Control Moment Gyroscope system proposed for the Apollo Telescope Mount cluster (later named Skylab) using momentum vector feedback. A compensation filtering technique is presented which significantly improved analytical and simulation performance of the system. This technique is quite similar to the complementary filtering technique and represents an early NASA application
Limb-darkening functions as derived from along-track operation of the ERBE scanning radiometers for August 1985
During August 1985, the scanning radiometers of the Earth Radiation Budget Experiment aboard the Earth Radiation Budget Satellite (ERBS) and the NOAA-9 satellite were operated in along-track scanning modes. These data were analyzed to produce limb darkening functions for Earth-emitted radiation, which relates the radiance in any given direction to the radiant exitence. Limb darkening functions are presented and shown as figures for day and night for each spacecraft. The scene types were computed using measurements within 10 deg of zenith. The models have values near zenith of 1.02 to 1.09, with values near 1.06 being typical. The typical value of the model is 1.06 for both day and night for ERBS, and for NOAA-9, the typical value at zenith is 1.06 for day and 1.05 for night. Mean models are formed for the ERBS and for the NOAA-9 results and are found to differ less than 1 percent, the ERBS results being the higher. The models vary about 1 percent with latitude near zenith
On the Relationship between Convex Bodies Related to Correlation Experiments with Dichotomic Observables
In this paper we explore further the connections between convex bodies
related to quantum correlation experiments with dichotomic variables and
related bodies studied in combinatorial optimization, especially cut polyhedra.
Such a relationship was established in Avis, Imai, Ito and Sasaki (2005 J.
Phys. A: Math. Gen. 38 10971-87) with respect to Bell inequalities. We show
that several well known bodies related to cut polyhedra are equivalent to
bodies such as those defined by Tsirelson (1993 Hadronic J. S. 8 329-45) to
represent hidden deterministic behaviors, quantum behaviors, and no-signalling
behaviors. Among other things, our results allow a unique representation of
these bodies, give a necessary condition for vertices of the no-signalling
polytope, and give a method for bounding the quantum violation of Bell
inequalities by means of a body that contains the set of quantum behaviors.
Optimization over this latter body may be performed efficiently by semidefinite
programming. In the second part of the paper we apply these results to the
study of classical correlation functions. We provide a complete list of tight
inequalities for the two party case with (m,n) dichotomic observables when
m=4,n=4 and when min{m,n}<=3, and give a new general family of correlation
inequalities.Comment: 17 pages, 2 figure
A Perturbative Approach to the Relativistic Harmonic Oscillator
A quantum realization of the Relativistic Harmonic Oscillator is realized in
terms of the spatial variable and {\d\over \d x} (the minimal canonical
representation). The eigenstates of the Hamiltonian operator are found (at
lower order) by using a perturbation expansion in the constant . Unlike
the Foldy-Wouthuysen transformed version of the relativistic hydrogen atom,
conventional perturbation theory cannot be applied and a perturbation of the
scalar product itself is required.Comment: 9 pages, latex, no figure
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