14,744 research outputs found
On the Hierarchical Preconditioning of the Combined Field Integral Equation
This paper analyzes how hierarchical bases preconditioners constructed for
the Electric Field Integral Equation (EFIE) can be effectively applied to the
Combined Field Integral Equation (CFIE). For the case where no hierarchical
solenoidal basis is available (e.g., on unstructured meshes), a new scheme is
proposed: the CFIE is implicitly preconditioned on the solenoidal Helmholtz
subspace by using a Helmholtz projector, while a hierarchical non-solenoidal
basis is used for the non-solenoidal Helmholtz subspace. This results in a
well-conditioned system. Numerical results corroborate the presented theory
Reforming the NCAA Drug-Testing Program to Withstand State Constitutional Scrutiny: An Analysis and Proposal
Shortly after year-round testing went into effect, the California Court of Appeal held that the NCAA\u27s original drug testing program violated a student-athlete\u27s right of privacy as protected by the California Constitution. This Note examines the impact of that decision and attempts to design a program that will withstand state constitutional scrutiny. Part I describes the current NCAA drug-testing program. Part II looks at the fourth amendment argument against drug testing of student-athletes. Part III assesses the viability of a federal constitutional attack on NCAA testing, while Part IV discusses a state constitutional challenge. Finally, Part V proposes reform of the current NCAA drug-testing program to achieve its goals within the bounds of federal and state constitutional rights of privacy
Constitutional Law - Income Tax - Self-Reporting Confronts Self-Incrimination: The Fifth Amendment in Retreat! - United States v. Milder, 329 F. Supp. 759 (D. Neb. 1971).
Detecting nonlocal Cooper pair entanglement by optical Bell inequality violation
Based on the Bardeen Cooper Schrieffer (BCS) theory of superconductivity, the
coherent splitting of Cooper pairs from a superconductor to two spatially
separated quantum dots has been predicted to generate nonlocal pairs of
entangled electrons. In order to test this hypothesis, we propose a scheme to
transfer the spin state of a split Cooper pair onto the polarization state of a
pair of optical photons. We show that the produced photon pairs can be used to
violate a Bell inequality, unambiguously demonstrating the entanglement of the
split Cooper pairs.Comment: 11 pages, 9 figures, v3 with added reference
Hamilton's Turns for the Lorentz Group
Hamilton in the course of his studies on quaternions came up with an elegant
geometric picture for the group SU(2). In this picture the group elements are
represented by ``turns'', which are equivalence classes of directed great
circle arcs on the unit sphere , in such a manner that the rule for
composition of group elements takes the form of the familiar parallelogram law
for the Euclidean translation group. It is only recently that this construction
has been generalized to the simplest noncompact group , the double cover of SO(2,1). The present work develops a theory of
turns for , the double and universal cover of SO(3,1) and ,
rendering a geometric representation in the spirit of Hamilton available for
all low dimensional semisimple Lie groups of interest in physics. The geometric
construction is illustrated through application to polar decomposition, and to
the composition of Lorentz boosts and the resulting Wigner or Thomas rotation.Comment: 13 pages, Late
Characterization of a Quantum Light Source Based on Spontaneous Parametric Down-Conversion
We have built a quantum light source capable of producing different types of
quantum states. The quantum light source is based on entangled state
preparation in the process of spontaneous parametric down-conversion. The
single-photon detection rate of eight-hundred thousand per second demonstrates
that we have created a bright state-of-the-art quantum light source. As a part
of the characterization we measured two-photon quantum interference in a
Hong-Ou-Mandel interferometer.Comment: 33 page
On the Spinning Motion of the Hovering Magnetic Top
In this paper we analyze the spinning motion of the hovering magnetic top. We
have observed that its motion looks different from that of a classical top. A
classical top rotates about its own axis which precesses around a vertical
fixed external axis. The hovering magnetic top, on the other hand, has its axis
slightly tilted and moves rigidly as a whole about the vertical axis. We call
this motion synchronous, because in a stroboscopic experiment we see that a
point at the rim of the top moves synchronously with the top axis. We show that
the synchronous motion may be attributed to a small deviation of the magnetic
moment from the symmetry axis of the top. We calculate the minimum angular
velocity required for stability in terms of the moments of inertia and magnetic
field and show that it is different from that of a classical top. We also give
experimental results that were taken with a top whose moment of inertia can be
changed. These results show very good agreement with our calculations.Comment: 19 pages (including 3 figures named fig1.eps-fig3.eps), uses amssymb,
epsf and amsbsy (AMSLaTeX
Assumptions that imply quantum dynamics is linear
A basic linearity of quantum dynamics, that density matrices are mapped
linearly to density matrices, is proved very simply for a system that does not
interact with anything else. It is assumed that at each time the physical
quantities and states are described by the usual linear structures of quantum
mechanics. Beyond that, the proof assumes only that the dynamics does not
depend on anything outside the system but must allow the system to be described
as part of a larger system. The basic linearity is linked with previously
established results to complete a simple derivation of the linear Schrodinger
equation. For this it is assumed that density matrices are mapped one-to-one
onto density matrices. An alternative is to assume that pure states are mapped
one-to-one onto pure states and that entropy does not decrease.Comment: 10 pages. Added references. Improved discussion of equations of
motion for mean values. Expanded Introductio
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