Physics doi: 10.3390/physics2020012

Authors: Masha Shcherbina Brunello Tirozzi Camillo Tassi

We find the free-energy in the thermodynamic limit of a one-dimensional XY model associated to a system of N qubits. The coupling among the &sigma; i z is a long range two-body random interaction. The randomness in the couplings is the typical interaction of the Hopfield model with p patterns ( p &lt; N ), where the patterns are p sequences of N independent identically distributed random variables (i.i.d.r.v.), assuming values &plusmn; 1 with probability 1 / 2 . We show also that in the case p &le; &alpha; N , &alpha; &ne; 0 , the free-energy is asymptotically independent from the choice of the patterns, i.e., it is self-averaging.

]]>Physics doi: 10.3390/physics2020011

Authors: Carlo Canepa

This work presents a computational study of a 232 Th -based homogeneous light-water reactor. Thorium reactors have been proposed as an alternative to the uranium fuel cycle since they exploit both the availability of thorium and its ability to afford fissile uranium isotopes by a sequence of neutron captures. Besides 233 U , as a result of the neutron captures, a significant amount of 234 U (36.3%) and 6.46% of 235 U are formed in the reactor under study. More importantly, the proposed simulation points out the possibility of a continuous withdrawal of the uranium isotopes without compromising the criticality and the power output of the reactor. This withdrawal affords the fissile material for the startup of reactors other than the first one, which requires a one-time only limited amount of fissile material. The significant molar fraction of the 234 U (0.17) in the extracted fuel does not pose a limitation on weapon proliferation, as a consequence of its high fission cross section for high-energy neutrons.

]]>Physics doi: 10.3390/physics2020010

Authors: Reinhard Schlickeiser Frank Schlickeiser

For Germany, it is predicted that the first wave of the corona pandemic disease reaches its maximum of new infections on 11 April 2020 &minus; 3.4 + 5.4 days with 90% confidence. With a delay of about 7 days the maximum demand on breathing machines in hospitals occurs on 18 April 2020 &minus; 3.4 + 5.4 days. The first pandemic wave ends in Germany end of May 2020. The predictions are based on the assumption of a Gaussian time evolution well justified by the central limit theorem of statistics. The width and the maximum time and thus the duration of this Gaussian distribution are determined from a statistical &chi; 2 -fit to the observed doubling times before 28 March 2020.

]]>Physics doi: 10.3390/physics2020009

Authors: Paul Kinsler

Faraday&rsquo;s Law of induction is often stated as &ldquo;a change in magnetic flux causes an electro-motive force (EMF)&rdquo;; or, more cautiously, &ldquo;a change in magnetic flux is associated with an EMF&rdquo;. It is as well that the more cautious form exists, because the first &ldquo;causes&rdquo; form can be shown to be incompatible with the usual expression V = &minus; &part; t &Phi; , where V is EMF, &part; t is a time derivative, and &Phi; is the magnetic flux.This is not, however, to deny the causality as reasonably inferred from experimental observation&mdash;it is the equation for Faraday&rsquo;s Law of induction which does not represent the claimed cause-and-effect relationship. Unusually, in this induction scenario, the apparent experimental causality does not match up with that of the mathematical model. Here we investigate a selection of different approaches, trying to see how an explicitly causal mathematical equation, which attempts to encapsulate the experimental ideas of &ldquo;a change in magnetic flux causes an EMF&rdquo;, might arise. We see that although it is easy to find mathematical models where changes in magnetic flux or field have an effect on the electric current, the same is not true for the EMF.

]]>Physics doi: 10.3390/physics2020008

Authors: G. Jordan Maclay

Radiation is a process common to classical and quantum systems with very different effects in each regime. In a quantum system, the interaction of a bound electron with its own radiation field leads to complex shifts in the energy levels of the electron, with the real part of the shift corresponding to a shift in the energy level and the imaginary part to the width of the energy level. The most celebrated radiative shift is the Lamb shift between the 2 s 1 / 2 and the 2 p 1 / 2 levels of the hydrogen atom. The measurement of this shift in 1947 by Willis Lamb Jr. proved that the prediction by Dirac theory that the energy levels were degenerate was incorrect. Hans Bethe&rsquo;s calculation of the shift showed how to deal with the divergences plaguing the existing theories and led to the understanding that interactions with the zero-point vacuum field, the lowest energy state of the quantized electromagnetic field, have measurable effects, not just resetting the zero of energy. This understanding led to the development of modern quantum electrodynamics (QED). This historical pedagogic paper explores the history of Bethe&rsquo;s calculation and its significance. It explores radiative effects in classical and quantum systems from different perspectives, with the emphasis on understanding the fundamental physical phenomena. Illustrations are drawn from systems with central forces, the H atom, and the three-dimensional harmonic oscillator. A first-order QED calculation of the complex radiative shift for a spinless electron is explored using the equations of motion and the m a s s 2 operator, describing the fundamental phenomena involved, and relating the results to Feynman diagrams.

]]>Physics doi: 10.3390/physics2010007

Authors: Viktor Dodonov

This is a digest of the main achievements in the wide area, called the Dynamical Casimir Effect nowadays, for the past 50 years, with the emphasis on results obtained after 2010.

]]>Physics doi: 10.3390/physics2010006

Authors: Vyacheslav I. Yukalov

The article presents the state of the art and reviews the literature on the long-standing problem of the possibility for a sample to be at the same time solid and superfluid. Theoretical models, numerical simulations, and experimental results are discussed.

]]>Physics doi: 10.3390/physics2010005

Authors: Satoshi Tanaka Kazuki Kanki

We theoretically study the dynamical Casimir effect (DCE), i.e., parametric amplification of a quantum vacuum, in an optomechanical cavity interacting with a photonic crystal, which is considered to be an ideal system to study the microscopic dissipation effect on the DCE. Starting from a total Hamiltonian including the photonic band system as well as the optomechanical cavity, we have derived an effective Floquet&ndash;Liouvillian by applying the Floquet method and Brillouin&ndash;Wigner&ndash;Feshbach projection method. The microscopic dissipation effect is rigorously taken into account in terms of the energy-dependent self-energy. The obtained effective Floquet&ndash;Liouvillian exhibits the two competing instabilities, i.e., parametric and resonance instabilities, which determine the stationary mode as a result of the balance between them in the dissipative DCE. Solving the complex eigenvalue problem of the Floquet&ndash;Liouvillian, we have determined the stationary mode with vanishing values of the imaginary parts of the eigenvalues. We find a new non-local multimode DCE represented by a multimode Bogoliubov transformation of the cavity mode and the photon band. We show the practical advantage for the observation of DCE in that we can largely reduce the pump frequency when the cavity system is embedded in a narrow band photonic crystal with a bandgap.

]]>Physics doi: 10.3390/physics2010004

Authors: Physics Editorial Office

The editorial team greatly appreciates the reviewers who have dedicated their considerable time and expertise to the journal’s rigorous editorial process over the past 12 months, regardless of whether the papers are finally published or not [...]

]]>Physics doi: 10.3390/physics2010003

Authors: Yan Francescato Simon R. Pocock Vincenzo Giannini

Herein we demonstrate the dramatic effect of non-locality on the plasmons which contribute to the Casimir forces, with a graphene sandwich as a case study. The simplicity of this system allowed us to trace each contribution independently, as we observed that interband processes, although dominating the forces at short separations, are poorly accounted for in the framework of the Dirac cone approximation alone, and should be supplemented with other descriptions for energies higher than 2.5 eV. Finally, we proved that distances smaller than 200 nm, despite being extremely relevant to state-of-the-art measurements and nanotechnology applications, are inaccessible with closed-form response function calculations at present.

]]>Physics doi: 10.3390/physics2010002

Authors: Gerd Leuchs Margaret Hawton Luis L. Sánchez-Soto

We present a new perspective on the link between quantum electrodynamics (QED) and Maxwell&rsquo;s equations. We demonstrate that the interpretation of the electric displacement vector D = &epsilon; 0 E , where E is the electric field vector and &epsilon; 0 is the permittivity of the vacuum, as vacuum polarization is consistent with QED. A free electromagnetic field polarizes the vacuum, but the polarization and magnetization currents cancel giving zero source current. The speed of light is a universal constant, while the fine structure constant, which couples the electromagnetic field to matter runs, as it should.

]]>Physics doi: 10.3390/physics2010001

Authors: Saverio Avino Enrico Calloni Sergio Caprara Martina De Laurentis Rosario De Rosa Tristano Di Girolamo Luciano Errico Gianluca Gagliardi Marco Grilli Valentina Mangano Maria Antonietta Marsella Luca Naticchioni Giovanni Piero Pepe Maurizio Perciballi Gabriel Pillant Paola Puppo Piero Rapagnani Fulvio Ricci Luigi Rosa Carlo Rovelli Paolo Ruggi Naurang L. Saini Daniela Stornaiuolo Francesco Tafuri Arturo Tagliacozzo

We present the status of the art of the Archimedes experiment, devoted to measuring the debated interaction of quantum vacuum fluctuations and gravity. The method is essentially the weighing of the transition energy of a layered superconductor where the contribution of vacuum energy to the transition energy is expected to be relevant. The transition is obtained by modulating the temperature of the superconducting sample at a frequency of about 10 mHz and the expected change of weight is measured with a suitably designed high sensitivity cryogenic beam balance. In this paper, we present an overview of the experiment, discussing the expected signal to be measured, and presenting in particular the result of a prototype balance operated in our present laboratory. In the frequency range of the measurement, the sensitivity is affected mainly by seismic, thermal, sensor, and control noise. We discuss these points showing in particular the design of the cryogenic apparatus, the final balance, and the quiet seismic site that will host the final measurement.

]]>Physics doi: 10.3390/physics1030031

Authors: Jen-Tsung Hsiang B. L. Hu

In this paper, we dwell on three issues: (1) revisit the relation between vacuum fluctuations and radiation reaction in atom-field interactions, an old issue that began in the 1970s and settled in the 1990s with its resolution recorded in monographs; (2) the fluctuation&ndash;dissipation relation (FDR) of the system, pointing out the differences between the conventional form in linear response theory (LRT) assuming ultra-weak coupling between the system and the bath, and the FDR in an equilibrated final state, relaxed from the nonequilibrium evolution of an open quantum system; (3) quantum radiation from an atom interacting with a quantum field: We begin with vacuum fluctuations in the field acting on the internal degrees of freedom (idf) of an atom, adding to its dynamics a stochastic component which engenders quantum radiation whose backreaction causes quantum dissipation in the idf of the atom. We show explicitly how different terms representing these processes appear in the equations of motion. Then, using the example of a stationary atom, we show how the absence of radiation in this simple cases is a result of complex cancellations, at a far away observation point, of the interference between emitted radiation from the atom and the local fluctuations in the free field. In so doing we point out in Issue 1 that the entity which enters into the duality relation with vacuum fluctuations is not radiation reaction, which can exist as a classical entity, but quantum dissipation. Finally, regarding issue 2, we point out for systems with many atoms, the co-existence of a set of correlation-propagation relations (CPRs) describing how the correlations between the atoms are related to the propagation of their (retarded non-Markovian) mutual influence manifesting in the quantum field. The CPR is absolutely crucial in keeping the balance of energy flows between the constituents of the system, and between the system and its environment. Without the consideration of this additional relation in tether with the FDR, dynamical self-consistency cannot be sustained. A combination of these two sets of relations forms a generalized matrix FDR relation that captures the physical essence of the interaction between an atom and a quantum field at arbitrary coupling strength.

]]>Physics doi: 10.3390/physics1030030

Authors: Luca Graziani

Here we introduce the latest version of the GAMESH model, capable to consistently account for the formation and evolution of compact binary systems along the cosmic assembly of a Milky Way (MW)-like galaxy, centered on a local group volume resolving a large population of dwarf satellites. After describing the galaxy assembly process and how the formation of binary systems is accounted for, we summarize some recent findings on the properties and evolution of low-metallicity dwarf galaxies hosting the birth/coalescence of stellar/compact binaries generating GW150914-like signals. Finally, we focus on the mass and orbital properties of the above compact binary candidates assessing their impact on the resulting coalescence times and on selecting suitable galaxy hosts.

]]>Physics doi: 10.3390/physics1030029

Authors: Alessandro Sergi Roberto Grimaudo Gabriel Hanna Antonino Messina

When a quantum field is in contact with a thermal bath, the vacuum state of the field may be generalized to a thermal vacuum state, which takes into account the thermal noise. In thermo field dynamics, this is realized by doubling the dimensionality of the Fock space of the system. Interestingly, the representation of thermal noise by means of an augmented space is also found in a distinctly different approach based on the Wigner transform of both the field operators and density matrix, which we pursue here. Specifically, the thermal noise is introduced by augmenting the classical-like Wigner phase space by means of Nos&eacute;&ndash;Hoover chain thermostats, which can be readily simulated on a computer. In this paper, we illustrate how this may be achieved and discuss how non-equilibrium quantum thermal distributions of the field modes can be numerically simulated.

]]>Physics doi: 10.3390/physics1030028

Authors: Nathaniel K. Hicks Amanda Bowman Katarina Godden

Radio-frequency (RF) charged particle traps, such as the Paul trap or higher order RF multipole traps, may be used to trap quasi-neutral plasma. The presence of positive and negative plasma species mitigates the ejection of particles that occurs due to space charge repulsion. For symmetric species, such as a pair plasma, the trapped particle distribution is essentially equal for both species. For plasma with species of disparate charge-to-mass ratio, the RF parameters are chosen to directly trap the lighter species, leading to loss of the heavier species until sufficient net space charge develops to prevent further loss. Two-dimensional (2D) electrostatic particle-in-cell simulations are performed of cases with mass ratio m+/m&minus; = 10, and also with ion&ndash;electron plasma. Multipole cases including order N = 2 (quadrupole) and higher order N = 8 (hexadecapole) are considered. The light ion-heavy ion N = 8 case exhibits particles losses less than 5% over 2500 RF periods, but the N = 8 ion&ndash;electron case exhibits a higher loss rate, likely due to non-adiabaticity of electron trajectories at the boundary, but still with low total electron loss current on the order of 10 &mu;A. The N = 2 ion-electron case is adiabatic and stable, but is subject to a smaller trapping volume and greater initial perturbation of the bulk plasma by the trapping field.

]]>Physics doi: 10.3390/physics1030027

Authors: Robin Smith Jack Bishop

We present an open-source kinematic fitting routine designed for low-energy nuclear physics applications. Although kinematic fitting is commonly used in high-energy particle physics, it is rarely used in low-energy nuclear physics, despite its effectiveness. A FORTRAN and ROOT C++ version of the FUNKI_FIT kinematic fitting code have been developed and published open access. The FUNKI_FIT code is universal in the sense that the constraint equations can be easily modified to suit different experimental set-ups and reactions. Two case studies for the use of this code, utilising experimental and Monte&ndash;Carlo data, are presented: (1) charged-particle spectroscopy using silicon-strip detectors; (2) charged-particle spectroscopy using active target detectors. The kinematic fitting routine provides an improvement in resolution in both cases, demonstrating, for the first time, the applicability of kinematic fitting across a range of nuclear physics applications. The ROOT macro has been developed in order to easily apply this technique in standard data analysis routines used by the nuclear physics community.

]]>Physics doi: 10.3390/physics1030026

Authors: Riccardo Maria Liberati Alessio Del Paggio Massimiliano Rossi

We propose a method for the estimation of the spectral response of a photodetector, using only the variation of the temperature of a black body source without the need of an expensive monochromator or a circular filter. The proposed method is suitable especially for infrared detectors in which the cut-off wavelength and the responsivity vs. wavelength is not exactly known. The method provides a rough estimation of the spectral response solving a Fredholm integral equation of the first kind. The precision of this technique depends on the temperatures at which the detector output is measured. Some examples are given for illustration.

]]>Physics doi: 10.3390/physics1030025

Authors: Malik Matwi

The canonical formulation of general relativity (GR) is based on decomposition space–time manifold M into R × Σ , where R represents the time, and Σ is the three-dimensional space-like surface. This decomposition has to preserve the invariance of GR, invariance under general coordinates, and local Lorentz transformations. These symmetries are associated with conserved currents that are coupled to gravity. These symmetries are studied on a three dimensional space-like hypersurface Σ embedded in a four-dimensional space–time manifold. This implies continuous symmetries and conserved currents by Noether’s theorem on that surface. We construct a three-form E i ∧ D A i (D represents covariant exterior derivative) in the phase space ( E i a , A a i ) on the surface Σ , and derive an equation of continuity on that surface, and search for canonical relations and a Lagrangian that correspond to the same equation of continuity according to the canonical field theory. We find that Σ i 0 a is a conjugate momentum of A a i and Σ i a b F a b i is its energy density. We show that there is conserved spin current that couples to A i , and show that we have to include the term F μ ν i F μ ν i in GR. Lagrangian, where F i = D A i , and A i is complex S O ( 3 ) connection. The term F μ ν i F μ ν i includes one variable, A i , similar to Yang–Mills gauge theory. Finally we couple the connection A i to a left-handed spinor field ψ , and find the corresponding beta function.

]]>Physics doi: 10.3390/physics1030024

Authors: Frans R. Klinkhamer Osvaldo P. Santillán Grigory E. Volovik Albert Zhou

We consider a finite-size spherical bubble with a nonequilibrium value of the q-field, where the bubble is immersed in an infinite vacuum with the constant equilibrium value q 0 for the q-field (this q 0 has already cancelled an initial cosmological constant). Numerical results are presented for the time evolution of such a q-bubble with gravity turned off and with gravity turned on. For small enough bubbles and a q-field energy scale sufficiently below the gravitational energy scale E Planck , the vacuum energy of the q-bubble is found to disperse completely. For large enough bubbles and a finite value of E Planck , the vacuum energy of the q-bubble disperses only partially and there occurs gravitational collapse near the bubble center.

]]>Physics doi: 10.3390/physics1020023

Authors: Anatoly Yu. Anikin Sergey Yu. Dobrokhotov Alexander I. Klevin Brunello Tirozzi

We study Gaussian wave beam and wave packet types of solutions to the linearized cold plasma system in a toroidal domain (tokamak). Such solutions are constructed with help of Maslov&rsquo;s complex germ theory (short-wave or semi-classical asymptotics with complex phases). The term &ldquo;semi-classical&rdquo; asymptotics is understood in a broad sense: asymptotic solutions of evolutionary and stationary partial differential equations from wave or quantum mechanics are expressed through solutions of the corresponding equations of classical mechanics. This, in particular, allows one to use useful geometric considerations. The small parameter of the expansion is h = &lambda; / 2 &pi; L where &lambda; is the wavelength and L the dimension of the system. In order to apply the asymptotic algorithm, we need this parameter to be small, so we deal only with high-frequency waves, which are in the range of lower hybrid waves used to heat the plasma. The asymptotic solution appears to be a Gaussian wave packet divided by the square root of the determinant of an appropriate Jacobi matrix (&ldquo;complex divergence&rdquo;). When this determinant is zero, focal points appear. Our approach allows one to write out asymptotics near focal points. We also claim that this approach is very practical and leads to formulas that can be used for numerical simulations in software like Wolfram Mathematica, Maple, etc. For the particular case of high-frequency beams, we present a recipe for constructing beams and packets and show the results of their numerical implementation. We also propose ideas to treat the more difficult general case of arbitrary frequency. We also explain the main ideas of asymptotic theory used to obtain such formulas.

]]>Physics doi: 10.3390/physics1020022

Authors: Denis Music Bastian Stelzer

Rutile TiO2, VO2, CrO2, MnO2, NbO2, RuO2, RhO2, TaO2, OsO2, IrO2, SnO2, PbO2, SiO2, and GeO2 (space group P42/mnm) were explored for thermal shock resistance applications using density functional theory in conjunction with acoustic phonon models. Four relevant thermomechanical properties were calculated, namely thermal conductivity, Poisson&rsquo;s ratio, the linear coefficient of thermal expansion, and elastic modulus. The thermal conductivity exhibited a parabolic relationship with the linear coefficient of thermal expansion and the extremes were delineated by SiO2 (the smallest linear coefficient of thermal expansion and the largest thermal conductivity) and PbO2 (vice versa). It is suggested that stronger bonding in SiO2 than PbO2 is responsible for such behavior. This also gave rise to the largest elastic modulus of SiO2 in this group of rutile oxides. Finally, the intrinsic thermal shock resistance was the largest for SiO2, exceeding some of the competitive phases such as Al2O3 and nanolaminated Ti3SiC2.

]]>Physics doi: 10.3390/physics1020021

Authors: Zurab Berezhiani Riccardo Biondi Yuri Kamyshkov Louis Varriano

We discuss the possibility of the transition magnetic moments (TMM) between the neutron n and its hypothetical sterile twin &ldquo;mirror neutron&rdquo; n&prime; from a parallel particle &ldquo;mirror&rdquo; sector. The neutron can be spontaneously converted into mirror neutron via the TMM (in addition to the more conventional transformation channel due to n&minus;n&prime; mass mixing) interacting with the magnetic field B as well as with mirror magnetic field B&prime;. We derive analytic formulae for the average probability of n&minus;n&prime; conversion and consider possible experimental manifestations of neutron TMM effects. In particular, we discuss the potential role of these effects in the neutron lifetime measurement experiments leading to new, testable predictions.

]]>Physics doi: 10.3390/physics1020020

Authors: Victor A. Abramovsky

The proof of the Abramovsky&mdash;Gribov&mdash;Kancheli (AGK) theorem for black hole physics is given. Based on the AGK relations, a formula for the luminosity of a black hole as a function of the mass of the black hole is derived. The correspondence to experimental data is considered. It is shown that the black holes of the galaxies NGC3842 and NGC4889 do not differ from those of the other galaxies.

]]>Physics doi: 10.3390/physics1020019

Authors: Sergey Adzhiev Janina Batishcheva Igor Melikhov Victor Vedenyapin

The question of constructing models for the evolution of clusters that differ in shape based on the Boltzmann&rsquo;s H-theorem is investigated. The first, simplest kinetic equations are proposed and their properties are studied: the conditions for fulfilling the H-theorem (the conditions for detailed and semidetailed balance). These equations are to generalize the classical coagulation&ndash;fragmentation type equations for cases when not only mass but also particle shape is taken into account. To construct correct (physically grounded) kinetic models, the fulfillment of the condition of detailed balance is shown to be necessary to monitor, since it is proved that for accepted frequency functions, the condition of detailed balance is fulfilled and the H-theorem is valid. It is shown that for particular and very important cases, the H-theorem holds: the fulfillment of the Arrhenius law and the additivity of the activation energy for interacting particles are found to be essential. In addition, based on the connection of the principle of detailed balance with the Boltzmann equation for the probability of state, the expressions for the reaction rate coefficients are obtained.

]]>Physics doi: 10.3390/physics1020018

Authors: Houri Ziaeepour

Gravitational Waves (GW) from coalescence of a Binary Neutron Star (BNS) and its accompanying short Gamma-Ray Burst (GRB) GW/GRB 170817A confirmed the presumed origin of these puzzling transients and opened up the way for relating properties of short GRBs to those of their progenitor stars and their surroundings. Here we review an extensive analysis of the prompt gamma-ray and late afterglows of this event. We show that a fraction of polar ejecta from the merger had been accelerated to ultra-relativistic speeds. This structured jet had an initial Lorentz factor of about 260 in our direction, which was O ( 10 ∘ ) from the jet&rsquo;s axis, and was a few orders of magnitude less dense than in typical short GRBs. At the time of arrival to circum-burst material the ultra-relativistic jet had a close to Gaussian profile and a Lorentz factor ≳ 130 in its core. It had retained in some extent its internal collimation and coherence, but had extended laterally to create mildly relativistic lobes&mdash;a cocoon. Its external shocks on the far from center inhomogeneous circum-burst material and low density of colliding shells generated slowly rising afterglows, which peaked more than 100 days after the prompt gamma-ray. The circum-burst material was somehow correlated with the merger. As non-relativistic outflows or tidally ejected material during BNS merger could not have been arrived to the location of the external shocks before the relativistic jet, circum-burst material might have contained recently ejected materials from resumption of internal activities, faulting and mass loss due to deformation and breaking of stars crusts by tidal forces during latest stages of their inspiral but well before their merger. By comparing these findings with the results of relativistic Magneto-Hydro-Dynamics (MHD) simulations and observed gravitational waves we conclude that progenitor neutron stars were most probably old, had close masses and highly reduced magnetic fields.

]]>Physics doi: 10.3390/physics1020017

Authors: Vitalii A. Okorokov

The magnetic field created in proton&ndash;proton and nucleus&ndash;nucleus collisions at ultra-high energies are studied with models of point-like charges and hard sphere for distribution of the constituents for vacuum conditions. The various beam ions are considered from light to heavy nuclei at energies corresponding to the nominal energies of the proton beam within the projects of further accelerator facilities high-energy Large Hadron Collider (HE-LHC) and Future Circular Collider (FCC). The magnetic-field strength immediately after collisions reaches the value tens of GeV 2 , while in the approach with point-like charges, some overestimate the amplitude of the field in comparison with more realistic hard-sphere model. The absolute value of the magnetic field rapidly decreases with time and increases with growth of atomic number. The amplitude for e B is estimated at level 100 GeV 2 to provide magnitude for quark&ndash;quark collisions at energies corresponding to the nominal energies of proton beams. These estimations are close to the range for onset of W boson condensation.

]]>Physics doi: 10.3390/physics1010016

Authors: Gianni Tallarita Moritz McGarrie

We determine the effective gravitational couplings in superspace whose components reproduce the supergravity Higgs effect for the constrained Goldstino multiplet. It reproduces the known Gravitino sector while constraining the off-shell completion. We show that these couplings arise by computing them as quantum corrections. This may be useful for phenomenological studies and model-building. We give an example of its application to multiple Goldstini.

]]>Physics doi: 10.3390/physics1010015

Authors: Ndolane Sene

In this paper, the integral balance methods of the Stokes’ first equation have been presented. The approximate solution of the fractional Stokes’ first equation using the heat balance integral method has been proposed. The approximate solution of the fractional Stokes’ first equation using the double integral methods has been proposed. The generalized fractional time derivative operator has been used. The graphical representations of the cubic profile and the quadratic profile for the Stokes’ first problem have been provided. The impacts of the orders of the generalized fractional derivative in the Stokes’ first problem have been investigated. The exponent of the assumed profile for the Stokes’ first equation has been discussed.

]]>Physics doi: 10.3390/physics1010014

Authors: Salvatore Capotosto Bailey Smoot Randal Hallford Preet Sharma

It is rather difficult to understand biological systems from a physics point of view, and understanding systems such as cancer is even more challenging. There are many factors affecting the dynamics of a cancer cell, and they can be understood approximately. We can apply the principles of non-equilibrium statistical mechanics and thermodynamics to have a greater understanding of such systems. Very much like other systems, living systems also transform energy and matter during metabolism, and according to the First Law of Thermodynamics, this could be described as a capacity to transform energy in a controlled way. The properties of cancer cells are different from regular cells. Cancer is a name used for a set of malignant cells that lost control over normal growth. Cancer can be described as an open, complex, dynamic, and self-organizing system. Cancer is considered as a non-linear dynamic system, which can be explained to a good degree using techniques from non-equilibrium statistical mechanics and thermodynamics. We will also look at such a system through its entropy due to to the interaction with the environment and within the system itself. Here, we have studied the entropy generation versus the entropy production approach, and have calculated the entropy of growth of cancer cells using Fokker-Planck equations.

]]>Physics doi: 10.3390/physics1010013

Authors: Syed Jamal Anwar M. Usman M. Ramzan M. Khalid Khan

We have investigated numerically the dynamics of quantum Fisher information (QFI) and quantum entanglement (QE) of a two moving two-level atomic systems interacting with a coherent and thermal field in the presence of intrinsic decoherence (ID) and Kerr (non-linear medium) and Stark effects. The state of the entire system interacting with coherent and thermal fields is evaluated numerically under the influence of ID and Kerr (nonlinear) and Stark effects. QFI and von Neumann entropy (VNE) decrease in the presence of ID when the atomic motion is neglected. QFI and QE show an opposite response during its time evolution in the presence of a thermal environment. QFI is found to be more susceptible to ID as compared to QE in the presence of a thermal environment. The decay of QE is further damped at greater time-scales, which confirms the fact that ID heavily influences the system&rsquo;s dynamics in a thermal environment. However, a periodic behavior of entanglement is observed due to atomic motion, which becomes modest under environmental effects. It is found that a non-linear Kerr medium has a prominent effect on the VNE but not on the QFI. Furthermore, it has been observed that QFI and QE decay soon under the influence of the Stark effect in the absence of atomic motion. The periodic response of QFI and VNE is observed for both the non-linear Kerr medium and the Stark effect in the presence of atomic motion. It is observed that the Stark, Kerr, ID, and thermal environment have significant effects during the time evolution of the quantum system.

]]>Physics doi: 10.3390/physics1010012

Authors: Basant Kumar Jha Yusuf Ya’u Gambo

In this paper, we have obtained an analytical solution to the problem of unsteady free convection and mass transfer flow of an incompressible fluid through a vertical channel in the presence of Dufour effect (or diffusion thermo). The bounding plates are assumed to have ramped wall temperature as well as specie concentration. The mathematical model responsible for the physical situation is presented in dimensionless form and solved analytically using the powerful Laplace Transform Technique (LTT) under relevant initial and boundary conditions. In order to cross check the accuracy of the analytical results, numerical solutions are obtained using PDEPE solver in MATLAB. The expressions for temperature, concentration, and velocity are obtained. The effects of Dufour parameter, Prandtl number ( P r ) , Schmidt number ( S c ) , and dimensionless time are described during the course of these discussions. The temperature, concentration, and velocity profiles are graphically presented for some realistic values of P r = 0.025 , &nbsp; 0.71 , &nbsp; 7.0 , &nbsp; 11.62 , &nbsp; 100.0 and S c = 0.22 , &nbsp; 0.60 , &nbsp; 1.00 , &nbsp; 2.62 , while the values of all other parameters are arbitrarily taken.

]]>Physics doi: 10.3390/physics1010011

Authors: Airton Deppman Eugenio Megías

In this work, we investigate fractal properties in Yang&ndash;Mills fields, in particular their Hausdorff fractal dimension. Fractal properties of quantum chromodynamics (QCD) have been suggested as the origin of power-law distributions in high energy collisions, as well as of non-extensive properties that have been observed experimentally. The fractal dimension obtained here can be calculated directly from the properties of the field theory.

]]>Physics doi: 10.3390/physics1010010

Authors: Andrea Addazi Antonino Marcianò Roman Pasechnik

We propose direct tests of very high energy first-order phase transitions, which are elusive to collider physics, deploying the gravitational waves&rsquo; measurements. We show that first-order phase transitions lying in a large window of critical temperatures, which is considerably larger than the electroweak energy scale, can be tested from advanced LIGO (aLIGO) and the Einstein Telescope. This provides the possibility to probe several inflationary mechanisms ending with the inflaton in a false minimum and high-energy first order phase transitions that are due to new scalar bosons, beyond the Standard Model of particle physics. As an important example, we consider the axion monodromy inflationary scenario and analyze the potential for its experimental verification, deploying the gravitational wave interferometers.

]]>Physics doi: 10.3390/physics1010009

Authors: Miguel-Angel Sanchis-Lozano Edward K. Sarkisyan-Grinbaum

In this paper, we consider the possibility that a new stage of matter stemming from hidden/dark sectors beyond the Standard Model, to be formed in p p collisions at the LHC (Large Hadron Collider), can significantly modify the correlations among final-state particles. In particular, two-particle azimuthal correlations are studied by means of a Fourier series sensitive to the near-side ridge effect while assuming that hidden/dark particles decay on top of the conventional parton shower. Then, new (fractional) harmonic terms should be included in the Fourier analysis of the azimuthal anisotropies, encoding the hypothetical new physics contribution and enabling its detection in a complementary way to other signatures.

]]>Physics doi: 10.3390/physics1010008

Authors: Peter Vadasz

The problem of nonlinear natural convection in a fluid saturated porous layer heated from below is reviewed focusing on the specific result of a collapse of the wave function. When the conditions for the onset of convection are met, a wave function is obtained as the solution of the linearized equations expressed in terms of a Fourier expansion. Only one mode of this expansion survives at the onset of convection, a result that can be seen as the “collapse of the wave function” in a very similar fashion as in quantum mechanics, although the explanations of the latter are very distinct from the ones in quantum mechanics. The reasons behind the “collapse of the wave function” result in natural convection are discussed and the analysis is extended into the nonlinear domain of convection, by using a weak nonlinear analysis.

]]>Physics doi: 10.3390/physics1010007

Authors: Revaz Beradze Merab Gogberashvili

In this paper we consider the properties of the 10 confirmed by the LIGO (Laser Interferometer Gravitational-Wave Observatory) Collaboration gravitational wave signals from the black hole mergers. We want to explain non-observation of electromagnetic counterpart and higher then expected merging rates of these events, assuming the existence of their sources in the hidden mirror universe. Mirror matter, which interacts with our world only through gravity, is a candidate of dark matter and its density can exceed ordinary matter density five times. Since mirror world is considered to be colder, star formation there started earlier and mirror black holes had more time to pick up the mass and to create more binary systems within the LIGO reachable zone. In total, we estimate factor of 15 amplification of black holes merging rate in mirror world with respect to our world, which is consistent with the LIGO observations.

]]>Physics doi: 10.3390/physics1010006

Authors: Gideon Alexander Boris Blok

It is shown that &alpha; s ( E ) , the strong coupling constant, can be determined in the non-perturbative regime from Bose-Einstein correlations (BEC). The obtained &alpha; s ( E ) , where E is the energy of the hadron in the center of mass reference frame of the di-hadron pair, is in agreement with the prescriptions dealt with in the Analytic Perturbative Theory approach. It also extrapolates smoothly to the standard perturbative &alpha; s ( E ) at higher energies. Our results indicate that BEC dimension can be considered as an alternative approach to the short-range correlations between hadrons.

]]>Physics doi: 10.3390/physics1010005

Authors: Maike A. F. dos Santos

In this work, we investigate a series of mathematical aspects for the fractional diffusion equation with stochastic resetting. The stochastic resetting process in Evans&ndash;Majumdar sense has several applications in science, with a particular emphasis on non-equilibrium physics and biological systems. We propose a version of the stochastic resetting theory for systems in which the reset point is in motion, so the walker does not return to the initial position as in the standard model, but returns to a point that moves in space. In addition, we investigate the proposed stochastic resetting model for diffusion with the fractional operator of Prabhakar. The derivative of Prabhakar consists of an integro-differential operator that has a Mittag&ndash;Leffler function with three parameters in the integration kernel, so it generalizes a series of fractional operators such as Riemann&ndash;Liouville&ndash;Caputo. We present how the generalized model of stochastic resetting for fractional diffusion implies a rich class of anomalous diffusive processes, i.e., &lang; ( &Delta; x ) 2 &rang; &prop; t &alpha; , which includes sub-super-hyper-diffusive regimes. In the sequence, we generalize these ideas to the fractional Fokker&ndash;Planck equation for quadratic potential U ( x ) = a x 2 + b x + c . This work aims to present the generalized model of Evans&ndash;Majumdar&rsquo;s theory for stochastic resetting under a new perspective of non-static restart points.

]]>Physics doi: 10.3390/physics1010004

Authors: Igor Dremin

The unitarity condition in the impact parameter space is used to obtain some information about the shape of the interaction region of colliding protons. It is shown that, strictly speaking, a reliable conclusion can be gained only if the behavior of the elastic scattering amplitude (especially, its imaginary part) at all transferred momenta is known. This information is currently impossible to obtain from experimentation. In practice, several assumptions and models are used. They lead to different results as shown below.

]]>Physics doi: 10.3390/physics1010003

Authors: Alessandro Strumia

The Born postulate can be reduced to its deterministic content that only applies to eigenvectors of observables: The standard probabilistic interpretation of generic states then follows from algebraic properties of repeated measurements and states. Extending this reasoning suggests an interpretation of quantum mechanics generalized with indefinite quantum norm.

]]>Physics doi: 10.3390/physics1010002

Authors: Chao Li Andrey Miroshnichenko

We construct a generalized system by introducing an additional long-range hopping to the well-known Su-Schrieffer-Heeger (SSH) model. This system exhibits richer topological properties including non-trivial topological phases and associated localized edge states. We study the zero-energy edge states in detail and derive the edge-state wave functions using two different methods. Furthermore, we propose a possible setup using octupole moments optically excited on an array of dielectric particles for the realization of the system, and by adjusting the coupling strengths between neighboring particles we can control the hotspots (near-field enhancement) in such structures.

]]>Physics doi: 10.3390/physics1010001

Authors: Edward K. Sarkisyan-Grinbaum

Herewith, we launch a new MDPI journal, Physics, for which I am honored to serve as Editor-in-Chief. [...]

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