Prospects to attain room temperature superconductivity

With a generic model for the electron-phonon spectral density, two simple expressions are derived to estimate the transition temperature and gap-to-temperature ratio in conventional superconductors. They entail that on average the numerical value of the phonon exchange factor, $\lambda$, is limited to 2.67, so that room temperature superconductivity may be attained only with a Debye temperature of about 1800 K or higher, in materials that may or may not involve hydrogen. They also show that a Be-Pb alloy may become a superconductor at $\sim$44 K.Comment: An application of the model to alloys is added to the manuscript, previously accepted into Solid State Communications on 03/05/1

Cooper Pairs in Alternating Layers of Light and Heavy Atoms

The Hamiltonian and trial function in the BCS theory are improved to test the limit of this theory. The Cooper pairs arise from standing electron waves, ready to move with atoms, giving high Tc. The Hamiltonian is derived from alternating layers of light and heavy atoms, giving a forbidden zone hosting no standing wave pairs. The exchange term may force singlet pairs into this zone, leaving triplet pairs outside, giving magnetic excitations. If the Fermi energy is crossed only by the CuO2 band, then the forbidden zone and triplet pairs will vanish, consistent with experimental evidence.Comment: 12 pages, 1 figure include

BCS Theory for Binary Systems with 2D Electrons

MgB_2 is considered as a binary system with 2D electrons. The classic BCS theory is applied to this system. The transition temperature is found to be relatively high, because 2D electrons are more capable of moving with the atoms, on top of other features of this system to enhance the electron-phonon interaction. This system may also shed light on the nature of superconductivity in cuprates.Comment: 4 pages, 1 figur

Quantum Mechanical Probability of Electrodynamic Particle(s)

A distribution of electromagnetic fields presents a statistical assembly of a particular type, which is at scale h a quantum statistical assembly itself and has also been instrumental to concretisation of the basic probability assumption of quantum mechanics. Of specific concern in this discussion is an extensive train of radiation fields, of a total wave function \psi, which are continuously (re)emitted and (re)absorbed by an oscillatory (point) charge of a zero rest mass and yet a finite dynamical mass, with the waves and charge together making up an extensive undulatory IED particle. The IED particle will as any real particle be subject to interactions with the environmental fields and particles, hence to excitations, and therefore will explore all possible states over time; at scale $h$ the states are discrete. On the basis of the principles of statistics and statistical mechanics combined with first principles solutions for the IED particle, we derive for the IED particle the probability functions in position space, of a form |\psi|^2, and in dynamical-variable space.Comment: Presentation at the 28th Int Colloq Group Theo Meth in Phys, Univ Northumbria, UK, July 25-30, 201

Vacuum Potentials for the Two Only Permanent Free Particles, Proton and Electron. Pair Productions

The two only species of isolatable, smallest, or unit charges +e and -e present in nature interact with the universal vacuum in a polarisable dielectric representation through two uniquely defined vacuum potential functions. All of the non-composite subatomic particles containing one-unit charges, +e or -e, are therefore formed in terms of the IED model of the respective charges, of zero rest masses, oscillating in either of the two unique vacuum potential fields, together with the radiation waves of their own charges. In this paper we give a first principles treatment of the dynamics of charge in a dielectric vacuum, based on which, combined with solutions for the radiation waves obtained previously, we subsequently derive the vacuum potential function for a given charge q, which we show to be quadratic and consist each of quantised potential levels, giving therefore rise to quantised characteristic oscillation frequencies of the charge and accordingly quantised, sharply-defined masses of the IED particles. By further combining with relevant experimental properties as input information, we determine the IED particles built from the charges +e,-e at their first excited states in the respective vacuum potential wells to be the proton and the electron, the observationally two only stable (permanently lived) and "free" particles containing one-unit charges. Their antiparticles as produced in pair productions can be accordingly determined. The characteristics of all of the other more energetic non-composite subatomic particles can also be recognised. We finally discuss the energy condition for pair production, which requires two successive energy supplies to (1) first disintegrate the bound pair of vaculeon charges +e,-e composing a vacuuon of the vacuum and (2) impart masses to the disintegrated charges.Comment: Presentation at the 7th Int Conf Quantum Theory and Symmetries (QTS 7) Prague, Aug., 2011. Includes Part B: "A Microscopic Theory of the Neutron". Includes Part C: "A Quantum Electromagnetic Theory of the Pions, Muons and Their Emitting Particles (I)

Critical Velocity for He II Superfluidity Motion in Channels Narrower than Micrometer

We derive an exact equation for the critical velocity for He II superfluidity motion in channels of width $<10^{-5}$ m for which no quantitatively satisfactory prediction exists prior to this work.Comment: 5 pages, 1 figure. Minor updat

The Theory of Superfluidity of 4^4Helium

I present here a microscopic theory for the superfluidity of $^4$He (He II) derived from experiments, and answer its essential questions. With a "momenton" model, the superfluid is shown to feature as a "harmonic superfluid". In which a new bonding type, the "superfluid bond", is formed. Its activation causes the anomalous thermal excitation, the large excess of specific heat, etc. The superfluidity mechanism is recognized being connected to a quantum confinement effect. The theory predicts the basic properties of He II in overall agreements with experiments. The series novel concepts evolved here reverse the current perceptions of $^4$He, give significant impact to the understandings of other superfluids.Comment: 4 pages (submitted to Phys Rev Lett), APS e-print: aps1999jan06_002, APS March Meeting: EC06 *** changes of this re-sub: provided 4 figure files, changed TeX file to "tighten style

Neutron Scattering by Superfluid He II about Dispersion Minimum

We derive the structure factor for superfluid He II about the energy dispersion minimum 1.93 1/A.Comment: 6 pages, no figure. Augmented reference lis

Continuous Emission of A Radiation Quantum

It is in accordance with such experiments as single photon self-interference that a photon, conveying one radiation energy quantum "$h \times$ frequency", is spatially extensive and stretches an electromagnetic wave train. A wave train, hence an energy quantum, can only be emitted by its source gradually. In both the two processes the wave and "particle" attributes of the radiation field are simultaneously prominent, where an overall satisfactory theory has been lacking. This paper presents a first principles treatment, in a unified framework of the classical and quantum mechanics, of the latter process, the emission of a single radiation quantum based on the dynamics of the radiation-emitting source, a charged oscillator which is itself extensive across its confining potential well. During the emission of one single radiation quantum, the extensive charged oscillator undergoes a continuous radiation damping and is non-stationary. This process is in this work treated using a quasi stationary approach, whereby the classical equation of motion, which directly facilitates the correspondence principle for a particle oscillator, and the quantum wave equation are established for each sufficiently brief time interval. As an inevitable consequence of the division of the total time for emitting one single quantum, a fractional Planck constant $h$ is introduced. The solutions to the two simultaneous equations yield for the charged oscillator a continuously exponentially decaying Hamiltonian that is at the same time quantised with respect to the fractional-$h$ at any instant of time; and the radiation wave field emitted over time stretches a wave train of finite length. The total system of the source and radiation field maintains at any time (integer $n$ times) one whole energy quantum, $h \times$ frequency, in complete accordance with the notion of quantum mechanics and experiment.Comment: Presentation at the XXIth Int Conf on Integrable Systems and Quantum Symmetries, Pragu

Inference of the Universal Constancy of Planck Constant based on First Principles

Since its discovery by Max Planck in 1900, the Planck constant $h$ has been demonstrated to be an universal constant, and its numerical value has been accurately determined based on experiments. Up to the present however the physical origin of this fundamental constant has not been well understood, and the numerical value of it has not been {\it ab initio} predicted. $h$ is characteristic in two respects: 1) it is a universal constant with respect to all (quasi-) stationary dynamical processes of all matter particles and radiation fields, and 2) it has a specific numerical value. A theoretical inference of $h$, and a corresponding accounting for the physical origin of $h$, therefore needs be achieved in both respects. This paper presents a theoretical exploration in the first respect, a mathematical inference of the universal constancy of $h$, based on the second law of thermodynamics, the principle of least action and the probability theory.Comment: Presentation at the International Workshop DICE, Castiglioncello (Tuscany), Italy, Sept, 201