arXiv subjects

Mario Rabinowitz

Publications and source records attributed to Mario Rabinowitz.

48 records · Page 3Linked to original sources

arXiv2003

Phenomenological theory of cuprate superconductivity

Reasonably good agreement with the superconducting transition temperatures of the cuprate high-Tc superconductors can be obtained on the basis of an approximate phenomenological theory. In this theory, two criteria are used to calculate the superconducting transition temperature. One is that the quantum wavelength is of the order of the electron-pair spacing. The other is that a very small fraction of the normal carriers exist as Cooper pairs at Tc. The resulting simple equation for Tc contains only two parameters: the normal carrier density and effective mass. We calculate specific transition temperatures for twelve cuprate superconductors.

cond-mat.supr-con↗

arXiv2003

In Memory of Julian Schwinger

Although he was the recipient of a Nobel Prize and despite the greatness of his accomplishments, Julian Schwinger is almost an unsung hero of our age . He is relatively unknown to the general population, even though in the physics community he was a renowned theoretician and teacher of physics. He shared the 1965 Nobel Prize in physics with Richard P. Feynman and Shin'ichiro Tomonaga for their development of Quantum Electrodynamics (QED). Of these three extraordinary physicists, and even of all the physicists that worked on QED, his work was the most rigorous and mathematically exacting.

physics.gen-ph↗

arXiv2003

Superconducting Power Generation

The superconducting ac generator has the greatest potential for large-scale commercial application of superconductivity that can benefit the public. Electric power is a vital ingredient of modern society, and generation may be considered to be the vital ingredient of a power system. This articles gives background, and an insight into the physics and engineering of superconducting power generation.

physics.gen-ph↗

arXiv2003

Examination of Wave-Particle Duality Via Two-Slit Interference

The wave-particle duality is the main point of demarcation between quantum and classical physics, and is the quintessential mystery of quantum mechanics. Young's two-slit interference experiment is the arch prototype of actual and gedanken experiments used as a testing ground of this duality. Quantum mechanics predicts that any detector capable of determining the path taken by a particle through one or the other of a two-slit plate will destroy the interference pattern. We will examine both the experimental and theoretical attempts to test this assertion, including a new kind of experiment, and to grasp the underlying truth behind this mystery from the earliest days to the present. Where positions differ, the views of both sides are presented in a balanced approach.

physics.gen-ph↗

arXiv2002

Little Black Holes:Dark Matter And Ball Lightning

Small,quiescent black holes can be considered as candidates for the missing dark matter of the universe,and as the core energy source of ball lightning.By means of gravitational tunneling,directed radiation is emitted from black holes in a process much attenuated from that of Hawking radiation,P SH, which has proven elusive to detect.Gravitational tunneling emission is similar to electric field emission of electronsfrom a metal in that a second body is involved which lowers the barrier and gives the barrier a finite rather than infinite width.Hawking deals with a single isolated black hole.

astro-ph↗

arXiv2002

Gravitational Tunneling Radiation

The isolated black hole radiation of both Hawking and Zel'dovich are idealized abstractions as there is always another body to distort the potential. This is considered with respect to both gravitational tunneling, and black hole "no-hair" theorems. The effects of a second body are to lower the gravitational barrier of a black hole and to give the barrier a finite rather than infinite width so tha a particle can escape by tunneling (as in field emission) or over the top of the lowered barrier (as in Schottky emission). Thus radiation may be emitted from black holes in a process differing from that of Hawking radiation, P SH, which has been undetected for over 24 years. The radiated power from a black hole derived here is PR e ^2__ PSH, where e ^2__ is he ransmission probability for radiation through the barrier. This is similar to electric field emission of electrons from a metal in that the emission can in principle be modulated and beamed. The temperature and entropy of black holes are reexamined. Miniscule black holes herein may help explain the missing mass of the universe, accelerated expansion of the universe, and anomalous rotation of spiral galaxies. A gravitational interference effect for black hole radiation similar to the Aharonov-Bohm effect is also examined.

astro-ph↗

arXiv2001

Macroscopic Hadronic Little Black Hole Interactions

Although the extraordinary weakness of gravity makes it by far the weakest of the interactions, viewing little black holes (LBH) as a class of elementary particles puts them in a league with hadrons as strongly interacting particles. They interact strongly both in the subatomic and macroscopic realms. An enormous universal gravitational attractive force ~ 10^43 /B 2 Newtons acts between identical black holes for any mass M >> M Planck at a center-to-center separation of 2 BR H (B > 1). For M ~ M Planck, there is a comparably large repulsive force. The Hawking model of LBH radiation permits a luminosity from a single LBH comparable to that of the entire universe, whereas this luminosity is greatly attenuated in the Rabinowitz model. In interacting with each other, and with large macroscopic bodies such as stars, neutron stars, and planets, LBH can exhibit strong interactions with large-scale manifestations. Although previously dismissed, an LBH is a potential candidate in accounting for the 1908 devastation of Tungus Siberia, since important LBH interactions were overlooked. LBH passing through neutron star pulsars are capable of causing a sudden change in frequency which may not be fully accounted for by other theories. The existence of black holes is also discussed.

astro-ph↗

arXiv2001

Phenomenological Theory of Superfluidity and Superconductivity

Quantum condensation is used here as the basis for a phenomenological theory of superfluidity and superconductivity. It leads to remarkably good calculations of the transition temperatures T c of superfluid 3 He and 4 He, as well as a large number of cuprate, heavy fermion, organic, dichalcogenide, and bismuth oxide super- conductors. Although this approach may apply least to the long coherence length metallics, reasonably good estimates are made for them, and chevral superconductors. T c for atomic H is estimated. T c can be calculated as a function of number density or density of states, and effective mass of normal carriers; or alternatively with the Fermi energy as the only input parameter. Predictions are made for a total of 26 superconductors and 4 superfluids. An estimate is also made for coherence lengths.

cond-mat.supr-con↗

arXiv2001

General model of pressure-induced transition temperature increase with focus on the Hg-Ba-Ca-Cu-O System

A general calculation of high pressure induced transition temperature (T c) increases for oxide superconductors gives a good description for the Hg-Ba-Ca-Cu-O system. Predictions are made of the maximum T^ cP theo =163, 154, and 111K compared with T^ cP exp = 164, 154, and 118K respectively for the superconducting phases of Hg-1223, Hg-1212, and Hg-1201 as a function of their compressibilities agreeing with experiment. The theoretical result is in the form of a universal scaling equation for the fractional change in T c as a function of pressure, which is derived from a recent phenomenological theory of short coherence length superconductivity.

cond-mat.supr-con↗

arXiv2001

Predictions of pressure-induced transition temperature increase for a variety of high temperature superconductors

A wide variety of superconducting oxides are used to test a general model of high pressure induced transition temperature (T c) changes. The T c 's vary from a low of 24 K to a high of 164 K. Although the model is capable of predicting both increases and decreases in T c with pressure, only superconductors that exhibit an increase are considered at this time. Predictions are made of the maximum T^ cP theo for 15 super-conductors as a function of their compressibilities. The theoretical results generally agree well with experiment. This model of T c as a function of pressure is derived from a recent successful phenomenological theory of short coherence length superconductivity.

cond-mat.supr-con↗

arXiv2001

Ball Lightning: Manifestation of Cosmic Little Black Holes

A case is made that in encounters with the earth's atmosphere, astrophysical little black holes (LBH) can manifest themselves as the core energy source of balllightning (BL). Relating the LBH incidence rate on earth to BL occurrence has the potential of shedding light on the distribution of LBH in the universe, and their velocities relative to the earth. Most BL features can be explained by a testable LBH model. Analyses are presented to support this model. LBH produce complex and many-faceted interactions in air directly and via their exhaust, resulting in excitation, ionization, and radiation due to processes such as gravitational and electrostatic tidal force, bremsstrahlung, pair production and annihilation, orbital electron near-capture by interaction with a charged LBH. Gravitational interaction of atmospheric atoms with LBH can result in an enhanced cross-section for polarization and ionization. An estimate for the power radiated by BL ~ Watts is in agreement with observation. An upper limit is found for the largest masses that can produce ionization and polarization excitation. It is shown that the LBH high power exhaust radiation is not prominent and its effects are consistent with observations.

astro-ph↗

arXiv2001

Do the Laws of Nature and Physics Agree About What is Allowed and Forbidden?

There are countless examples in the history of science that not only were the laws of physics often incomplete and more limited in their domain of validity than was realized, but at times they missed the mark completely. Despite this, our collective memory is often short on such matters, focusing on present triumphs and quickly forgetting past failures. This makes us less tolerant to that which challenges present orthodoxy. It may be of value to recall such past deficiences as well as present shortcomings, particularly since science may always be encumbered with such limitations. We can avoid serious pitfalls if we let the past serve as a guide to the future. Subjects covered will include Godel's theorem, superconductivity, zero-point energy, the quantum and classical Aharonov-Bohm and similar effects, theories of general relativity, Mach's principle, black hole radiation, ball lightning, and the universe(s).

physics.hist-ph↗