SEARCH · Searcharxiv

Results for “physics.gen-ph”

Search indexed arXiv papers on artificial intelligence, large language models, computer vision and robotics. Read source abstracts and follow links to arXiv.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 127 records · Page 7Linked to original sources

arXiv2007

Penrose Model potential, compared with Coleman-Weinberg Potential for early universe scalar evolution

We present an overview of Dr. Penrose's model of a cyclic universe, minus the big crunch which relies upon black hole collection of matter after an a long term expansion phase from an initial big bang . We affirm that the suggested evolution equation presented at his lecture for his model meets requirements as to an emergent quintessence field from a vacuum state . We try to offer suggestions as to how to investigate his controversial conformal mapping of matter/energy via Hawkings radiation from a potentially infinite number of black holes to a new big bang. This is his 'ripples in a pond' effect which we find highly unusual but worth serious study and investigation.

physics.gen-ph↗

arXiv2009

Cluster-Spin Gaussian Model for Lattice-Ising Models

In this paper we lay special stress on analyzing the topological properties of the lattice systems and try to ovoid the conventional ways to calculate the critical points. Only those clusters with finite sizes can execute the self similar transformations of infinite hierarchies. Each ordered cluster has fractal dimension, their minimum relates to the edge fixed point, which accords with the transformations fixed point relating to a critical point. There are two classes of systems and clusters by their connectivity. Using mathematic mapping method we set up cluster-spin Gaussian model solved accurately. There are single state and -fold coupling state in a reducible cluster, each of which corresponds to a subsystem described by a Gaussian model. By the minimal fractal dimension a final expression of the critical points is obtained. The critical points of three lattice systems are calculated, our method makes the calculations very simplified and highly accurate. A possibility of existence of different clusters at the critical temperature is discussed.

physics.gen-ph↗

arXiv2007

The Scientific Manuscripts left Unpublished by Ettore Majorana (with outlines of his life and work)

We present a panoramic view of the main scientific manuscripts left unpublished by the brightest Italian theoretical physicist of the XX century, Ettore Majorana. We deal in particular: (i) with his very original "study" notes (the so-called "Volumetti"), already published by us in English, in 2003, c/o Kluwer Acad.Press, Dordrecht & Boston, and in the original Italian language, in 2006, c/o Zanichelli pub., Bologna, Italy; and (ii) with a selection of his research notes (the so-called "Quaderni"), that we shall publish c/o Springer, Berlin. We seize the present opportunity for setting forth also some suitable -scarcely known- information about Majorana's life and work, on the basis of documents (letters, testimonies, different documents...) discovered or collected by ourselves during the last decades. [A finished, enlarged version of this paper will appear as the editors' Preface, at the beginning of the coming book "Ettore Majorana - Unpublished Research Notes on Theoretical Physics", edited by S.Esposito, E.Recami, A.van der Merwe and R.Battiston, to be printed by Springer verlag, Berlin].

physics.hist-ph↗

arXiv2009

Exponential Maps and Symmetric Transformations in Cluster-Spin System for Lattice-Ising Models

We defined exponential maps with one parameter, associated with geodesics on the parameter surface. By group theory we proposed a formula of the critical points, which is a direct sum of the Lie subalgebras at the critical temperature. We consider the self similar transformations as symmetric operations. In the opinion of symmetry we analyzed the hexagon lattice system, and got its three cluster spin states: single, double, and threefold, then its critical point is calculated. There are two cases for lattice-Ising model in thermodynamic equilibrium. In one case the periodic boundary conditions are present without the infinite self similar transformations; in another the system is in the possibility of the infinite self similar transformations without the conditions. We think the real exact critical points close to our results.

physics.gen-ph↗

arXiv2007

Trouble with Physics?

This is a review of Lee Smolin's "The Trouble with Physics". The main gist of the review is that the physics of the past three decades has been rich with new discoveries in a large number of domains. The Standard Model, while providing a successful framework for the electroweak and strong interactions still needs to be developed further to fully account fot the mass of strong interaction data collected over the decades. A multitude of new phenomena have been discovered however, or predicted theoretically, in the physics of very low temperatures (e.g. fractional Hall effect, Bose-Einstein condensation) and quantum macroscopic effects (liquid crystals, high temperature superconductivity), some of which remain to be fully explained. Therefore if there is any "Trouble with Physics", as implied by the author of this book, it mainly concerns speculative work on Superstring theory, which may or may not turn out to agree with the results of observation. The subject as a whole does not appear to be in trouble.

physics.hist-ph↗

arXiv2007

How do black holes move, as quantum objects or as classical objects?

Results of a recent study of the transition between quantum and classical behavior are applied to black holes. The study led to a criterion separating quantum from classical behavior on the basis of mass or size, dependent on local effects of cosmic expansion. Application of this criterion to black holes indicates that the motion of smaller black holes will be characteristically quantum mechanical, while the motion of larger black holes must be classical, with a threshold distinguishing these behaviors at a Schwartzschild radius of roughly the size of a nucleon.

physics.gen-ph↗

arXiv2008

Deformation potential dominated phonons in ZnS quantum dots

Strong deformation potential (DP) dominated Raman spectra are reported for quantum confined cubic ZnS nanoclusters under off-resonance conditions allowed only in quantum dots. A flurry of zone boundary phonons is demonstrated in the scattering process. Transverse optic (TO) mode in the multi-phonon process shows only even order overtones suggesting the dominance of a two-phonon process (having large DP value in ZnS) and its integral multiples. Two-phonon TO modes corresponding to A1 and B2 symmetries are also demonstrated under off-resonance conditions which are allowed only in quantum dots.

physics.optics↗

arXiv2007

Update on Ion Studies

The effect of ions has received one of the highest priorities in R&D for the damping rings of the International Linear Collider(ILC). It is detrimental to the performance of the electron damping ring. In this note, an update concerning the ion studies for the ILC damping ring is given. We investigate the gap role and irregular fill pattern in the ring.The ion density reduction in different fills is calculated analytically. Simulation results are also presented.

physics.acc-ph↗

arXiv2007

Maxwell equations in Riemannian space-time, geometry effect on material equations in media

The known possibility to consider the (vacuum) Maxwell equations in a curved space-time as Maxwell equations in flat space-time(Mandel'stam L.I., Tamm I.E.) taken in an effective media the properties of which are determined by metrical structure of the curved model is studied. Metrical structure of the curved space-time generates effective constitutive equations for electromagnetic fields, the form of four corresponding symmetrical tensors is found explicitly for general case of an arbitrary Riemannian space - time. Four constitutive tensors are not independent and obey some additional constraints between them. Several simple examples are specified in detail:itis given geometrical modeling of the anisotropic media (magnetic crystals) and the geometrical modeling of a uniform media in moving reference frame in the Minkowsky electrodynamics -- the latter is realized trough the use of a non-diagonal metrical tensor determined by 4-vector velocity of the moving uniform media. Also the effective material equations generated by geometry of space of constant curvature (Lobachevsky and Riemann models) are determined.

physics.class-ph↗

arXiv2009

Field equations of electromagnetic and gravitational fields

The paper studies the validity of Maxwell equation in the case for coexistence of electromagnetic field and gravitational field. With the algebra of quaternions, the Newton's law of gravitation is the same as that in classical theory of gravitational field. Meanwhile the Maxwell equation is identical with that in classical theory of electromagnetic field. And the related conclusions can be spread to the case for coexistence of electromagnetic field and gravitational field by the algebra of octonions. The study claims that Maxwell equation keeps unchanged in the case for coexistence of gravitational field and electromagnetic field, except for the direction of displacement current.

physics.gen-ph↗

arXiv2007

S-Parameter Uncertainties in Network Analyzer Measurements with Application to Antenna Patterns

An analytical method was developed, to estimate uncertainties in full two-port Vector Network Analyzer measurements, using total differentials of S-parameters. System error uncertainties were also estimated from total differentials involving two triples of standards, in the Direct Through connection case. Standard load uncertainties and measurement inaccuracies were represented by independent differentials. Complex uncertainty in any quantity, differentiably dependent on S-parameters, is estimated by the corresponding Differential Error Region. Real uncertainties, rectangular and polar, are estimated by the orthogonal parallelogram and annular sector circumscribed about the Differential Error Region, respectively. From the user's point of view, manufactures' data may be used to set the independent differentials and apply the method. Demonstration results include: (1) System error differentials for Short, matching Load and Open pairs of opposite sex standards; (2) System error uncertainties for VNA extended by two lengthy transmission lines of opposite sex end-connectors; (3) High uncertainties in Z-parameters against frequency of an appropriately designed, DC resistive, T-Network; (4) Moderate uncertainties in amplitude and phase patterns of a designed UHF radial discone antenna (azimuthally rotated by a built positioner, under developed software control of a built hardware controller) polarization coupled with a constructed gain standard antenna (stationary) into an anechoic chamber.

physics.gen-ph↗

arXiv2009

Basic outlines of a new hypothesis on physical reality

The papers mentioned in the bibliography lead to this new hypothesis which constitutes a wide panorama of the physical reality. Its coherence and its simplicity are virtues that make interesant to gaze upon it.

physics.gen-ph↗

arXiv2007

The importance of probability interference in social science: rationale and experiment

Probability interference is a fundamental characteristic of quantum mechanics. In this paper we attempt to show with the help of some examples, where this fundamental trait of quantum physics can be found back in a social science environment. In order to support our thesis that interference can possibly be found back in many other macro-scopic areas, we proceed in setting up an experimental test.

physics.gen-ph↗

arXiv2007

100 Years of dimensional analysis: New steps toward empirical law deduction

On the verge of the centenary of dimensional analysis (DA), we present a generalisation of the theory and a methodology for the discovery of empirical laws from observational data. It is well known that DA: a) reduces the number of free parameters, b) guarantees scale invariance through dimensional homogeneity and c) extracts functional information encoded in the dimensionless grouping of variables. Less known are the results of Rudolph and co-workers that DA also gives rise to a new pair of transforms - the similarity transform (S) that converts physical dimensional data into dimensionless space and its inverse (S'). Here, we present a new matrix generalisation of the Buckingham Theorem, made possible by recent developments in the theory of inverse non-square matrices, and show how the transform pair arises naturally. We demonstrate that the inverse transform S' is non-unique and how this casts doubt on scaling relations obtained in cases where observational data has not been referred to in order to break the degeneracy inherent in transforming back to dimensional (physical) space. As an example, we show how the underlying functional form of the Planck Radiation Law can be deduced in only a few lines using the matrix method and without appealing to first principles; thus demonstrating the possibility of a priori knowledge discovery; but that subsequent data analysis is still required in order to identify the exact causal law. It is hoped that the proof presented here will give theoreticians confidence to pursue inverse problems in physics using DA.

physics.class-ph↗

arXiv2008

Pioneer anomaly: a drift in the proper time of the spacecraft

A relativistic theory is proposed to explain the anomalous accelerations of Pioneer 10/11, Galileo and Ulysses spacecrafts. The theory points out at the limitations of the weak field approximation and proposes a drift in the proper time of the spacecraft outside the framework of general relativity. The theory yields a very accurate and precise value for the anomalous acceleration. In this theory the proper time of a body is associated with the gravitational frequency shift of the constituent fundamental particles of the body. The frequency shift changes the energy level of the body which gets reflected in its relativistic mass and therefore in its motion. This change in energy level causes the time like geodesics to deviate from that of the standard theoretical models. We introduce proper time in the line element of a metric theory according to a fixed set of rules laid down by general relativity for introducing deviation in the flat Minkowski metric. The frequency shift for bodies of different composition traversing different trajectories however, is not the same and this gets reflected in its motion as an unmodeled anomalous effect. This association of proper time with the gravitational frequency shift of the body requires the flat Minkowski metric to deviate in different ways for different two body systems. The solution to Pioneer anomaly given here yields anomalous acceleration within the limits of observational accuracy. Gravitational redshift of light, bending of light and perihelic precession of planets are within the permissible limits. The theory shows that Einstein's field equations do provide some clue to the Pioneer anomaly but the solution is not very accurate. The theory can also explain the rotation curves of the spiral galaxies.

physics.gen-ph↗

arXiv2007

Einstein, Sciascia, Majorana, Amaldi, e il Rapporto tra Intellettuali e Potere (Einstein, Sciascia, Majorana, Amaldi, and the Relationship of Intellectuals with the Power)

In Europe (e.g., in Italy), and in the States, the opinion is widely spreading that the negative consequences of modern progress are the fault of "Science". A lively debate on this topic took place among the famous writer Leonardo Sciascia and Italian physicists like Edoardo Amaldi and Emilio Segre', when Sciascia wrote his known book about the disappearance of Ettore Majorana, a book that presented Majorana (a very reserved theoretical physicist) as an example of the scientist that keeps his discoveries secret when afraid of possible evil applications. We wish to contribute now to such a question, since many special meetings did recently return to it, while celebrating the centenary of Majorana's birth (2006), or 30 years (2005) from Sciascia's book publication. It appeared natural to us to start with the figure of Einstein, who, even if extremely peaceable, supported the atomic bomb construction by his letter to Roosvelt. We discuss first the significance of part of Einsteins's scientific work (which flourished in particular one century ago): We seize this opportunity for presenting a derivation of the "twins paradox", so simple that it has been taught to Senior High School last-year students or University undergraduate students; all the present work, more in general, is addressed mainly to them. In the second part of this paper, we analyse the general meaning of Einstein's contributions to philosophy and pedagogy. The third part is entirely devoted to our main subject, i.e., to discussing the "Responsibility of the Intellectuals". The reader interested chiefly in this last part, can find it re-expounded in a self-contained way in the Appendix. More information in the Contents of this article.

physics.gen-ph↗

arXiv2008

Wheeler's Gravitomagnetism Revisited I: A Purely Lorentz-Compton Approach to Vector Gravitational Waves and Trio-Holes

A theory of vector gravitational waves is presented on the basis of an additional gravitational field, recovering ideas that go back to H. A. Lorentz, field that A. Wheeler called ``gravitomagnetism''. The theory is independent of Einstein's General Relativity Theory, but is consistent with the Einstein-Lorentz framework of Special Relativity, so that the resulting equations are considered exact from the start, and not approximations valid for velocities small compared with the speed of light. A simple model of mass formation and presence of angular momentum started with a new type of singularity, ``trio-holes'', is exhibited.

physics.gen-ph↗

arXiv2007

The Method of the Description of Dynamics Nonequilibrium Systems within the Frames of the Classical Mechanics

Within the frames of the analytical mechanics the method of the description of dynamics of nonequilibrium systems of potentially interacting elements is develops. The method is based on an opportunity of representation of nonequilibrium system by set of interacting equilibrium subsystems. The equation of motion of interacting subsystems is found. Based on it the Lagrange, Hamilton and Liouville equations for subsystems are obtained. The expression of an entropy production is found. The way of a substantiation of thermodynamics in the frames of classical mechanic is offered.

physics.gen-ph↗