3,249,748 research outputs found
Quantum Global Strings and Their Correlation Functions
A full quantum description of global vortex strings is presented in the
framework of a pure Higgs system with a broken global U(1) symmetry in 3+1D. An
explicit expression for the string creation operator is obtained, both in terms
of the Higgs field and in the dual formulation where a Kalb-Ramond
antisymmetric tensor gauge field is employed as the basic field. The quantum
string correlation function is evaluated and from this, the string energy
density is obtained. Potential application in cosmology (cosmic strings) and
condensed matter (vortices in superfluids) are discussed.Comment: 14 pages, latex, no figure
Neutrino Oscillations for Dummies
The reality of neutrino oscillations has not really sunk in yet. The
phenomenon presents us with purely quantum mechanical effects over macroscopic
time and distance scales (milliseconds and 1000s of km). In order to help with
the pedagogical difficulties this poses, I attempt here to present the physics
in words and pictures rather than math. No disrespect is implied by the title;
I am merely borrowing a term used by a popular series of self-help books
Osculating spaces to secant varieties
We generalize the classical Terracini's Lemma to higher order osculating
spaces to secant varieties. As an application, we address with the so-called
Horace method the case of the -Veronese embedding of the projective 3-space
Pressurized panel
Large area pressurized meteoroid penetration detector panels with maximum inherent structural rigidity are provided. The panels measure directly the penetration rate in materials to be used in spacecraft. Panel structure include an interconnected cellular configuration in which the cells have spaced periphery welds and tufts in their centers. A spot weld is made at the center point joining the panels
Application of fuel/time minimization techniques to route planning and trajectory optimization
Rising fuel costs combined with other economic pressures have resulted in industry requirements for more efficient air traffic control and airborne operations. NASA has responded with an on-going research program to investigate the requirements and benefits of using new airborne guidance and pilot procedures that are compatible with advanced air traffic control systems and that will result in more fuel efficient flight. The results of flight testing an airborne computer algorithm designed to provide either open-loop or closed-loop guidance for fuel efficient descents while satisfying time constraints imposed by the air traffic control system is summarized. Some of the potential cost and fuel savings that are obtained with sophisticated vertical path optimization capabilities are described
Entanglement and optimal strings of qubits for memory channels
We investigate the problem of enhancement of mutual information by encoding
classical data into entangled input states of arbitrary length and show that
while there is a threshold memory or correlation parameter beyond which
entangled states outperform the separable states, resulting in a higher mutual
information, this memory threshold increases toward unity as the length of the
string increases. These observations imply that encoding classical data into
entangled states may not enhance the classical capacity of quantum channels.Comment: 14 pages, 8 figures, latex, accepted for publication in Physical
Review
Continuously variable voltage-controlled phase shifter
Phase shifter circuit adjusts the phase relationship between a locally generated reference frequency and a received RF signal applied to a phase-coherent detector. It is small enough to be integrated into a receiver subassembly and operates on command from remote control panels
Simplified method measures changes in tensile yield strength using least number of specimens
Simplified method determines yield strength due to heat treat, irradiation or mechanical treatment. Each specimen in a group of specimens is tested for yield stress point, subjected to heat treat or irradiation, and retested for new yield stress point which is a measure of change in material
Thermally activated foaming compositions Patent
Storage stable, thermally activated foaming compositions for erecting and rigidizing mechanisms of thin sheet solar collector
Impact testing machine Patent
Impact testing machine for imparting large impact forces on high velocity package
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