Journal Description
Particles
Particles
is an international, open access, peer-reviewed journal covering all aspects of nuclear physics, particle physics and astrophysics science, and is published quarterly online by MDPI.
- Open Access— free for readers, with article processing charges (APC) paid by authors or their institutions.
- High Visibility: indexed within Scopus, ESCI (Web of Science), Inspec, CAPlus / SciFinder, and other databases.
- Journal Rank: CiteScore - Q2 (Physics and Astronomy (miscellaneous))
- Rapid Publication: manuscripts are peer-reviewed and a first decision is provided to authors approximately 19.6 days after submission; acceptance to publication is undertaken in 5.6 days (median values for papers published in this journal in the second half of 2023).
- Recognition of Reviewers: reviewers who provide timely, thorough peer-review reports receive vouchers entitling them to a discount on the APC of their next publication in any MDPI journal, in appreciation of the work done.
Impact Factor:
1.4 (2022);
5-Year Impact Factor:
1.3 (2022)
Latest Articles
Quantum Limit for the Emittance of Dirac Particles Carrying Orbital Angular Momentum
Particles 2024, 7(1), 264-274; https://doi.org/10.3390/particles7010015 - 17 Mar 2024
Abstract
In this article, we highlight that the interaction potential confining Dirac particles in a box must be invariant under the charge conjugation to avoid the Klein paradox, in which an infinite number of negative-energy particles are excited. Furthermore, we derive the quantization rules
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In this article, we highlight that the interaction potential confining Dirac particles in a box must be invariant under the charge conjugation to avoid the Klein paradox, in which an infinite number of negative-energy particles are excited. Furthermore, we derive the quantization rules for a relativistic particle in a cylindrical box, which emulates the volume occupied by a beam of particles with a non-trivial aspect ratio. We apply our results to the evaluation of the quantum limit for emittance in particle accelerators. The developed theory allows the description of quantum beams carrying Orbital Angular Momentum (OAM). We demonstrate how the degeneracy pressure is such to increase the phase–space area of Dirac particles carrying OAM. The results dramatically differ from the classical evaluation of phase–space areas, that would foresee no increase in emittance for beams in a coherent state of OAM. We discuss the quantization of the phase–space cell’s area for single Dirac particles carrying OAM, and, finally, provide an interpretation of the beam entropy as the measure of how much the phase–space area occupied by the beam deviates from its quantum limit.
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(This article belongs to the Special Issue Feature Papers for Particles 2023)
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New Aspect of Chiral SU(2) and U(1) Axial Breaking in QCD
by
Chuan-Xin Cui, Jin-Yang Li, Shinya Matsuzaki, Mamiya Kawaguchi and Akio Tomiya
Particles 2024, 7(1), 237-263; https://doi.org/10.3390/particles7010014 - 09 Mar 2024
Abstract
The violation of the axial symmetry in QCD is stricter than the chiral breaking simply because of the presence of the quantum axial anomaly. If the QCD gauge coupling is sent to zero (the
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The violation of the axial symmetry in QCD is stricter than the chiral breaking simply because of the presence of the quantum axial anomaly. If the QCD gauge coupling is sent to zero (the asymptotic free limit, where the axial anomaly does not exist), the strength of the axial breaking coincides with that of the chiral breaking, which we, in short, call an axial–chiral coincidence. This coincidence is trivial since QCD then becomes a non-interacting theory. Actually, there exists another limit in the QCD parameter space, where an axial–chiral coincidence occurs even with nonzero QCD gauge coupling, which can be dubbed a nontrivial coincidence: it is the case with the massive light quarks and the massless strange quark ( ) due to the flavor-singlet nature of the topological susceptibility. This coincidence is robust and tied to the anomalous chiral Ward–Takahashi identity, which is operative even at hot QCD. This implies that the chiral symmetry is restored simultaneously with the axial symmetry at high temperatures. This simultaneous restoration is independent of and, hence, is irrespective of the order of the chiral phase transition. In this paper, we discuss how the real-life QCD can be evolved from the nontrivial chiral–axial coincidence limit by working on a Nambu–Jona–Lasinio model with the axial anomaly contribution properly incorporated. It is shown that, at high temperatures, the large differences between the restorations of the chiral symmetry and the axial symmetry for two light quarks and a sufficiently large current mass for the strange quark are induced by a significant interference of the topological susceptibility. Thus, the deviation from the nontrivial coincidence, which is monitored by the strange quark mass controlling the topological susceptibility, provides a new way of understanding the chiral and axial breaking in QCD.
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(This article belongs to the Collection High Energy Physics)
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Open AccessCommunication
Experimental Study of Cold Dense Nuclear Matter
by
Maria Patsyuk, Timur Atovullaev, Goran Johansson, Dmitriy Klimanskiy, Vasilisa Lenivenko, Sergey Nepochatykh and Eli Piasetzky
Particles 2024, 7(1), 229-236; https://doi.org/10.3390/particles7010013 - 08 Mar 2024
Abstract
The fundamental theory of nuclear interactions, Quantum Chromodynamics (QCD), operates in terms of quarks and gluons at higher resolution. At low resolution the relevant degrees of freedom are nucleons. Two-nucleon Short-Range Correlations (SRC) help to interconnect these two descriptions. SRCs are temporary fluctuations
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The fundamental theory of nuclear interactions, Quantum Chromodynamics (QCD), operates in terms of quarks and gluons at higher resolution. At low resolution the relevant degrees of freedom are nucleons. Two-nucleon Short-Range Correlations (SRC) help to interconnect these two descriptions. SRCs are temporary fluctuations of strongly interacting close pairs of nucleons. The distance between the two nucleons is comparable to their radii and their relative momenta are larger than the fermi sea level. According to the electron scattering experiments held in the last decade, SRCs have far-reaching impacts on many-body systems, the nucleon-nucleon interactions, and nuclear substructure. The modern experiments with ion beams and cryogenic liquid hydrogen target make it possible to study properties of the nuclear fragments after quasi-elastic knockout of a single nucleon or an SRC pair. Here we review the status and perspectives of the SRC program in so-called inverse kinematics at JINR (Dubna, Russia). The first SRC experiment at the BM@N spectrometer (2018) with 4 GeV/c/nucleon carbon beam has shown that detection of an intact 11B nucleus after interaction selects out the quasi-elastic knockout reaction with minimal contribution of initial- and final-state interactions. Also, 25 events of SRC-breakups showed agreement in SRC properties as known from electron beam experiments. The analysis of the second measurement of SRC at BM@N held in 2022 with an improved setup is currently ongoing. The SRC project at JINR moved to a new experimental area in 2023, where the next measurement is being planned in terms of experimental setup and physics goals.
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(This article belongs to the Special Issue Infinite and Finite Nuclear Matter (INFINUM))
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Open AccessArticle
Surface Vibrations of Bubble-like Superheavy Nuclei
by
Şerban Mişicu
Particles 2024, 7(1), 214-228; https://doi.org/10.3390/particles7010012 - 05 Mar 2024
Abstract
The shape vibrations of a superheavy nucleus with a complete (bubble) or a partially (semi-bubble) depleted density in its central region and sharp-edge inner and outer surfaces are investigated in the frame of the Liquid-Drop Model. The quadrupole oscillations of the two existing
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The shape vibrations of a superheavy nucleus with a complete (bubble) or a partially (semi-bubble) depleted density in its central region and sharp-edge inner and outer surfaces are investigated in the frame of the Liquid-Drop Model. The quadrupole oscillations of the two existing surfaces are coupled in both velocity and coordinate and, upon decoupling, a low-energy and a high-energy component are predicted. The electric transition probabilities are estimated for the decay of the low-lying mode first state to the ground state for the entire range of the radius and density of the depleted core.
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(This article belongs to the Special Issue Feature Papers for Particles 2023)
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Exploring the Distribution and Impact of Bosonic Dark Matter in Neutron Stars
by
Davood Rafiei Karkevandi, Mahboubeh Shahrbaf, Soroush Shakeri and Stefan Typel
Particles 2024, 7(1), 201-213; https://doi.org/10.3390/particles7010011 - 03 Mar 2024
Abstract
The presence of dark matter (DM) within neutron stars (NSs) can be introduced by different accumulation scenarios in which DM and baryonic matter (BM) may interact only through the gravitational force. In this work, we consider asymmetric self-interacting bosonic DM, which can reside
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The presence of dark matter (DM) within neutron stars (NSs) can be introduced by different accumulation scenarios in which DM and baryonic matter (BM) may interact only through the gravitational force. In this work, we consider asymmetric self-interacting bosonic DM, which can reside as a dense core inside the NS or form an extended halo around it. It is seen that depending on the boson mass ( ), self-coupling constant ( ) and DM fraction ( ), the maximum mass, radius and tidal deformability of NSs with DM admixture will be altered significantly. The impact of DM causes some modifications in the observable features induced solely by the BM component. Here, we focus on the widely used nuclear matter equation of state (EoS) called DD2 for describing NS matter. We show that by involving DM in NSs, the corresponding observational parameters will be changed to be consistent with the latest multi-messenger observations of NSs. It is seen that for MeV and , DM-admixed NSs with are consistent with the maximum mass and tidal deformability constraints.
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(This article belongs to the Special Issue Selected Papers from “Dark Matter and Stars: Multi-Messenger Probes of Dark Matter and Modified Gravity”)
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The Impact of Asymmetric Dark Matter on the Thermal Evolution of Nucleonic and Hyperonic Compact Stars
by
Edoardo Giangrandi, Afonso Ávila, Violetta Sagun, Oleksii Ivanytskyi and Constança Providência
Particles 2024, 7(1), 179-200; https://doi.org/10.3390/particles7010010 - 27 Feb 2024
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We investigate the impact of asymmetric fermionic dark matter (DM) on the thermal evolution of neutron stars (NSs), considering a scenario where DM interacts with baryonic matter (BM) through gravity. Employing the two-fluid formalism, our analysis reveals that DM accrued within the NS
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We investigate the impact of asymmetric fermionic dark matter (DM) on the thermal evolution of neutron stars (NSs), considering a scenario where DM interacts with baryonic matter (BM) through gravity. Employing the two-fluid formalism, our analysis reveals that DM accrued within the NS core exerts an inward gravitational pull on the outer layers composed of BM. This gravitational interaction results in a noticeable increase in baryonic density within the core of the NS. Consequently, it strongly affects the star’s thermal evolution by triggering the early onsets of the direct Urca (DU) processes, causing enhanced neutrino emission and rapid star cooling. Moreover, the photon emission from the star’s surface is modified due to a reduction in radius. We demonstrate the effect of DM gravitational pull on nucleonic and hyperonic DU processes that become kinematically allowed even for NSs of low mass. We then discuss the significance of observing NSs at various distances from the Galactic center. Given that the DM distribution peaks toward the Galactic center, NSs within this central region are expected to harbor higher fractions of DM, potentially leading to distinct cooling behaviors.
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A New Look at b → s Observables in 331 Models
by
Francesco Loparco
Particles 2024, 7(1), 161-178; https://doi.org/10.3390/particles7010009 - 27 Feb 2024
Abstract
Flavour changing neutral current (FCNC) processes are described by loop diagrams in the Standard Model (SM), while in 331 models, based on the gauge group ,
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Flavour changing neutral current (FCNC) processes are described by loop diagrams in the Standard Model (SM), while in 331 models, based on the gauge group , they are dominated by tree-level exchanges of a new heavy neutral gauge boson . By exploiting this feature, observables related to FCNC decays of K, and mesons can be considered in several variants of 331 models. The variants are distinguished by the value of a parameter that plays a key role in this framework. Imposing constraints on the observables, we select possible ranges for the mass of the boson in correspondence to the values , with . The results are used to determine the impact of 331 models on processes and on the correlations among them, in the light of new experimental data recently released.
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(This article belongs to the Special Issue Feature Papers for Particles 2023)
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Testing Higher Derivative Gravity through Tunnelling
by
Ruth Gregory and Shi-Qian Hu
Particles 2024, 7(1), 144-160; https://doi.org/10.3390/particles7010008 - 16 Feb 2024
Abstract
Higher derivative terms in the gravitational action are natural from the perspective of quantum gravity, but are perceived as leading to a lack of well-posedness. The Gauss–Bonnet term has second-order equations of motion, but does not impact gravitational dynamics in 4D, so one
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Higher derivative terms in the gravitational action are natural from the perspective of quantum gravity, but are perceived as leading to a lack of well-posedness. The Gauss–Bonnet term has second-order equations of motion, but does not impact gravitational dynamics in 4D, so one might expect that it is not physically relevant. We discuss how signatures can show up in tunnelling processes and whether these will likely be physically accessible in Higgs vacuum decay.
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(This article belongs to the Special Issue Selected Papers from “Testing Gravity 2023”)
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Numerical Modeling of Erosion in Hall Effect Thrusters
by
Matteo Passet, Mario Panelli and Francesco Battista
Particles 2024, 7(1), 121-143; https://doi.org/10.3390/particles7010007 - 30 Jan 2024
Abstract
The erosion of the accelerating chamber walls is one of the main factors limiting the operational life of Hall effect thrusters (HETs), and it is mainly related to the sputtering of ceramic walls due to the impacting energetic ion particles. The erosion phenomenon
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The erosion of the accelerating chamber walls is one of the main factors limiting the operational life of Hall effect thrusters (HETs), and it is mainly related to the sputtering of ceramic walls due to the impacting energetic ion particles. The erosion phenomenon is investigated by means of a numerical model that couples the plasma model HYPICFLU2, used for evaluating the local distributions of ion energies and incidence angles, and a sputtering model specific for the xenon–Borosil pair, which is the most used in HETs application. The sputtering yield model is based on the measurements by Ranjan et al. that are improved with a linear factor to include wall temperature effect, recently studied by Parida et al. The experimental eroded profiles of SPT100 walls are selected as benchmark. The results show that there is a decrease in erosion speed with time, in accordance with experimental measurements, but the model underestimates, by about 50–60%, the erosion at the channel exit, which suggests a stronger dependence of sputter yield on surface temperature. Thus, the need for new experimental measurements of sputtering in the range of impact energy, angle, and wall temperature, respectively, of 10–250 eV, 0–85°, 30–600 °C, arises.
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(This article belongs to the Special Issue Feature Papers for Particles 2023)
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Searching for Dark Matter Axions via Atomic Excitations
by
J. D. Vergados, S. Cohen, F. T. Avignone and R. Creswick
Particles 2024, 7(1), 96-120; https://doi.org/10.3390/particles7010006 - 27 Jan 2024
Abstract
Axions can be considered as good dark matter candidates. The detection of such light particles can be achieved by observing axion-induced atomic excitations. The target is in a magnetic field so that the m-degeneracy is removed, and the energy levels can be
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Axions can be considered as good dark matter candidates. The detection of such light particles can be achieved by observing axion-induced atomic excitations. The target is in a magnetic field so that the m-degeneracy is removed, and the energy levels can be suitably adjusted. Using an axion-electron coupling indicated by the limit obtained by the Borexino experiment, which is quite stringent, reasonable axion absorption rates have been obtained for various atomic targets The obtained results depend, of course, on the atom considered through the parameters (the spin−orbit splitting) as well as ( the energy splitting due to the magnetic moment interaction). This assumption allows axion masses in the tens of eV if the transition occurs between members of the same multiplet, i.e., , and axion masses in the range 1 meV–1 eV for transitions of the spin−orbit splitting type , i.e., three types of transition. The axion mass that can be detected is very close to the excitation energy involved, which can vary by adjusting the magnetic field. Furthermore, since the axion is absorbed by the atom, the calculated cross-section exhibits the behavior of a resonance, which can be exploited by experiments to minimize any background events.
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(This article belongs to the Special Issue Feature Papers for Particles 2023)
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Towards Uncovering Dark Matter Effects on Neutron Star Properties: A Machine Learning Approach
by
Prashant Thakur, Tuhin Malik and Tarun Kumar Jha
Particles 2024, 7(1), 80-95; https://doi.org/10.3390/particles7010005 - 15 Jan 2024
Cited by 2
Abstract
Over the last few years, researchers have become increasingly interested in understanding how dark matter affects neutron stars, helping them to better understand complex astrophysical phenomena. In this paper, we delve deeper into this problem by using advanced machine learning techniques to find
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Over the last few years, researchers have become increasingly interested in understanding how dark matter affects neutron stars, helping them to better understand complex astrophysical phenomena. In this paper, we delve deeper into this problem by using advanced machine learning techniques to find potential connections between dark matter and various neutron star characteristics. We employ Random Forest classifiers to analyze neutron star (NS) properties and investigate whether these stars exhibit characteristics indicative of dark matter admixture. Our dataset includes 32,000 sequences of simulated NS properties, each described by mass, radius, and tidal deformability, inferred using recent observations and theoretical models. We explore a two-fluid model for the NS, incorporating separate equations of state for nucleonic and dark matter, with the latter considering a fermionic dark matter scenario. Our classifiers are trained and validated in a variety of feature sets, including the tidal deformability for various masses. The performance of these classifiers is rigorously assessed using confusion matrices, which reveal that NS with admixed dark matter can be identified with approximately 17% probability of misclassification as nuclear matter NS. In particular, we find that additional tidal deformability data do not significantly improve the precision of our predictions. This article also delves into the potential of specific NS properties as indicators of the presence of dark matter. Radius measurements, especially at extreme mass values, emerge as particularly promising features. The insights gained from our study are pivotal for guiding future observational strategies and enhancing the detection capabilities of dark matter in NS. This study is the first to show that the radii of neutron stars at 1.4 and 2.07 solar masses, measured using NICER data from pulsars PSR J0030+0451 and PSR J0740+6620, strongly suggest that the presence of dark matter in a neutron star is more likely than only hadronic composition.
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(This article belongs to the Special Issue Selected Papers from “Dark Matter and Stars: Multi-Messenger Probes of Dark Matter and Modified Gravity”)
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Fermion Proca Stars: Vector-Dark-Matter-Admixed Neutron Stars
by
Cédric Jockel and Laura Sagunski
Particles 2024, 7(1), 52-79; https://doi.org/10.3390/particles7010004 - 09 Jan 2024
Cited by 2
Abstract
Dark matter could accumulate around neutron stars in sufficient amounts to affect their global properties. In this work, we study the effect of a specific model for dark matter—a massive and self-interacting vector (spin-1) field—on neutron stars. We describe the combined systems of
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Dark matter could accumulate around neutron stars in sufficient amounts to affect their global properties. In this work, we study the effect of a specific model for dark matter—a massive and self-interacting vector (spin-1) field—on neutron stars. We describe the combined systems of neutron stars and vector dark matter using Einstein–Proca theory coupled to a nuclear matter term and find scaling relations between the field and metric components in the equations of motion. We construct equilibrium solutions of the combined systems, compute their masses and radii, and also analyze their stability and higher modes. The combined systems admit dark matter (DM) core and cloud solutions. Core solutions compactify the neutron star component and tend to decrease the total mass of the combined system. Cloud solutions have the inverse effect. Electromagnetic observations of certain cloud-like configurations would appear to violate the Buchdahl limit. This could make Buchdahl-limit-violating objects smoking gun signals for dark matter in neutron stars. The self-interaction strength is found to significantly affect both mass and radius. We also compare fermion Proca stars to objects where the dark matter is modeled using a complex scalar field. We find that fermion Proca stars tend to be more massive and geometrically larger than their scalar field counterparts for equal boson masses and self-interaction strengths. Both systems can produce degenerate masses and radii for different amounts of DM and DM particle masses.
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(This article belongs to the Special Issue Selected Papers from “Dark Matter and Stars: Multi-Messenger Probes of Dark Matter and Modified Gravity”)
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First Results of Studying EAS Cores Using a High-Mountain Ionization Calorimeter
by
Turlan Sadykov, Rauf Mukhamedshin, Vladimir Galkin, Alia Argynova, Aidana Almenova, Korlan Argynova, Khanshaiym Makhmet, Olga Novolodskaya, Tunyk Idrissova, Valery Zhukov, Vyacheslav Piscal and Zhakypbek Sadykov
Particles 2024, 7(1), 40-51; https://doi.org/10.3390/particles7010003 - 28 Dec 2023
Abstract
In high-altitude experiments to study the central cores of EAS at E0 ≳ 1016 eV (√s ≳ 5 TeV) using X-ray emulsion chambers and ionization calorimeters, phenomena such as the coplanarity of the arrival of the most energetic particles in super
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In high-altitude experiments to study the central cores of EAS at E0 ≳ 1016 eV (√s ≳ 5 TeV) using X-ray emulsion chambers and ionization calorimeters, phenomena such as the coplanarity of the arrival of the most energetic particles in super families of γ-rays and hadrons and a so-called Tien Shan effect (too slow absorption of cascades initiated by high-energy hadrons in the calorimeter) were observed. These effects could not be reproduced within the framework of theoretical models of the 80s and 90s. The coplanarity is explained via a process of coplanar generation of the most energetic secondary particles in interactions of super high-energy hadrons with nuclei of air atoms. Perhaps the Tien Shan effect could be explained using a high cross section for the generation of fragmentation-region charmed hadrons. To study these phenomena, a new set of detectors has been developed, including the world’s highest high-mountain ionization calorimeter, “Hadron-55”. This paper presents the initial experimental results.
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(This article belongs to the Special Issue Innovative Techniques for Particle Physics in Space)
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Stationary Schrödinger Equation and Darwin Term from Maximal Entropy Random Walk
by
Manfried Faber
Particles 2024, 7(1), 25-39; https://doi.org/10.3390/particles7010002 - 26 Dec 2023
Cited by 1
Abstract
We describe particles in a potential by a special diffusion process, the maximal entropy random walk (MERW) on a lattice. Since MERW originates in a variational problem, it shares the linear algebra of Hilbert spaces with quantum mechanics. The Born rule appears from
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We describe particles in a potential by a special diffusion process, the maximal entropy random walk (MERW) on a lattice. Since MERW originates in a variational problem, it shares the linear algebra of Hilbert spaces with quantum mechanics. The Born rule appears from measurements between equilibrium states in the past and the same equilibrium states in the future. Introducing potentials by the observation that time, in a gravitational field running in different heights with a different speed, MERW respects the rule that all trajectories of the same duration are counted with equal probability. In this way, MERW allows us to derive the Schrödinger equation for a particle in a potential and the Darwin term of the nonrelativistic expansion of the Dirac equation. Finally, we discuss why quantum mechanics cannot be simply a result of MERW, but, due to the many analogies, MERW may pave the way for further understanding.
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(This article belongs to the Special Issue Feature Papers for Particles 2023)
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From Scalar Clouds to Rotating Hairy Black Holes
by
Gustavo García, Marcelo Salgado, Philippe Grandclément and Eric Gourgoulhon
Particles 2024, 7(1), 1-24; https://doi.org/10.3390/particles7010001 - 21 Dec 2023
Abstract
First, we review the solutions of a complex-valued scalar field, termed scalar clouds, with and without electric charge, when coupled to a rotating Kerr–Newman (electrically charged) or Kerr (neutral) black hole (BH), respectively. To this aim, we determine the conditions and parameters
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First, we review the solutions of a complex-valued scalar field, termed scalar clouds, with and without electric charge, when coupled to a rotating Kerr–Newman (electrically charged) or Kerr (neutral) black hole (BH), respectively. To this aim, we determine the conditions and parameters that characterize the existence of solutions that represent bound states, with an energy-momentum tensor that respect the symmetries of the underlying spacetimes, even if the backreaction of the field is not taken into account at this stage. In particular, we show that in the extremal Kerr scenario the cloud solutions exist only when the mass of the BH satisfies certain bounds, which are obtained by analyzing an effective potential associated with the radial dependency of the scalar clouds that leads to a Schrödinger-like equation. Second, when the backreaction of the field in the spacetime is taken into account, we present a family of stationary, axisymmetric and asymptotically flat solutions of the Einstein–Klein–Gordon system that represent genuine rotating hairy black holes (RHBHs) and provide different values of some global quantities associated with them, such as the Komar mass and the Komar angular momentum. We also compute RHBH solutions with nodes in the radial part of the scalar field and also for a higher azimuthal number m.
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(This article belongs to the Special Issue Selected Papers from “Testing Gravity 2023”)
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Open AccessArticle
Finiteness of
by
Igor Kondrashuk and Ivan Schmidt
Particles 2023, 6(4), 993-1008; https://doi.org/10.3390/particles6040063 - 08 Nov 2023
Cited by 7
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We argue in favor of the independence on any scale, ultraviolet or infrared, in kernels of the effective action expressed in terms of dressed superfields for the case of super-Yang–Mills theory. Under “scale independence” of the effective
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We argue in favor of the independence on any scale, ultraviolet or infrared, in kernels of the effective action expressed in terms of dressed superfields for the case of super-Yang–Mills theory. Under “scale independence” of the effective action of dressed mean superfields, we mean its “finiteness in the off-shell limit of removing all the regularizations”. This off-shell limit is scale independent because no scale remains inside these kernels after removing the regularizations. We use two types of regularization: regularization by dimensional reduction and regularization by higher derivatives in its supersymmetric form. Based on the Slavnov–Taylor identity, we show that dressed fields of matter and of vector multiplets can be introduced to express the effective action in terms of them. Kernels of the effective action expressed in terms of such dressed effective fields do not depend on the ultraviolet scale. In the case of dimensional reduction, by using the developed technique, we show how the problem of inconsistency of the dimensional reduction can be solved. Using Piguet and Sibold formalism, we indicate that the dependence on the infrared scale disappears off shell in both the regularizations.
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Open AccessReview
Neutrino Masses in Supersymmetric Models with R-Symmetry
by
Marcos Cardoso Rodriguez and Ion Vasile Vancea
Particles 2023, 6(4), 975-992; https://doi.org/10.3390/particles6040062 - 08 Nov 2023
Abstract
In this article, we give a brief review of the origin of the neutrino mass in some interesting non-linear supersymmetric models with R-symmetry. These models are able to address and solve the most important problems of particle physics and provide mechanisms for
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In this article, we give a brief review of the origin of the neutrino mass in some interesting non-linear supersymmetric models with R-symmetry. These models are able to address and solve the most important problems of particle physics and provide mechanisms for neutrino mass generation and their mixing parameters in agreement with the current experimental data. Their prediction could be experimentally tested in the near future by collider experiments.
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Off-Shell Duality Invariance of Schwarzschild Perturbation Theory
by
Adam R. Solomon
Particles 2023, 6(4), 943-974; https://doi.org/10.3390/particles6040061 - 07 Nov 2023
Abstract
We explore the duality invariance of the Maxwell and linearized Einstein–Hilbert actions on a non-rotating black hole background. On-shell, these symmetries are electric–magnetic duality and Chandrasekhar duality, respectively. Off-shell, they lead to conserved quantities; we demonstrate that one of the consequences of these
[...] Read more.
We explore the duality invariance of the Maxwell and linearized Einstein–Hilbert actions on a non-rotating black hole background. On-shell, these symmetries are electric–magnetic duality and Chandrasekhar duality, respectively. Off-shell, they lead to conserved quantities; we demonstrate that one of the consequences of these conservation laws is that even- and odd-parity metric perturbations have equal Love numbers. Along the way, we derive an action principle for the Fackerell–Ipser equation and Teukolsky–Starobinsky identities in electromagnetism.
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(This article belongs to the Special Issue Selected Papers from “Testing Gravity 2023”)
Open AccessArticle
Order, Chaos and Born’s Distribution of Bohmian Particles
by
Athanasios C. Tzemos and George Contopoulos
Particles 2023, 6(4), 923-942; https://doi.org/10.3390/particles6040060 - 01 Nov 2023
Abstract
We study order, chaos and ergodicity in the Bohmian trajectories of a 2D quantum harmonic oscillator. We first present all the possible types (chaotic, ordered) of Bohmian trajectories in wavefunctions made of superpositions of two and three energy eigenstates of the oscillator. There
[...] Read more.
We study order, chaos and ergodicity in the Bohmian trajectories of a 2D quantum harmonic oscillator. We first present all the possible types (chaotic, ordered) of Bohmian trajectories in wavefunctions made of superpositions of two and three energy eigenstates of the oscillator. There is no chaos in the case of two terms and in some cases of three terms. Then, we show the different geometries of nodal points in bipartite Bohmian systems of entangled qubits. Finally, we study multinodal wavefunctions and find that a large number of nodal points does not always imply the dominance of chaos. We show that, in some cases, the Born distribution is dominated by ordered trajectories, something that has a significant impact on the accessibility of Born’s rule by initial distributions of Bohmian particles with .
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(This article belongs to the Special Issue Feature Papers for Particles 2023)
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Poincaré–Chetaev Equations in Dirac’s Formalism of Constrained Systems
by
Alexei A. Deriglazov
Particles 2023, 6(4), 913-922; https://doi.org/10.3390/particles6040059 - 13 Oct 2023
Cited by 5
Abstract
We single out a class of Lagrangians on a group manifold, for which one can introduce non-canonical coordinates in the phase space, which simplify the construction of the Poisson structure without explicitly calculating the Dirac bracket. In the case of the
[...] Read more.
We single out a class of Lagrangians on a group manifold, for which one can introduce non-canonical coordinates in the phase space, which simplify the construction of the Poisson structure without explicitly calculating the Dirac bracket. In the case of the manifold, the application of this formalism leads to the Poincaré–Chetaev equations. The general solution to these equations is written in terms of an exponential of the Hamiltonian vector field.
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Particles
Infinite and Finite Nuclear Matter (INFINUM)
Guest Editors: David Blaschke, Evgeni Kolomeitsev, Nikolai Antonenko, Victor Braguta, Isaac VidañaDeadline: 15 April 2024
Special Issue in
Particles
Innovative Techniques for Particle Physics in Space
Guest Editors: Francesco Maria Follega, Francesco NozzoliDeadline: 21 May 2024
Special Issue in
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Feature Papers for Particles 2023
Guest Editor: Armen SedrakianDeadline: 20 June 2024
Special Issue in
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Selected Papers from "The Modern Physics of Compact Stars and Relativistic Gravity 2023"
Guest Editor: Aram SaharianDeadline: 31 October 2024
Topical Collections
Topical Collection in
Particles
The 50 Years of Relativistic Heavy Ion Experiments Using Accelerator Systems
Collection Editor: Alexandru Jipa
Topical Collection in
Particles
Dark Matter and New Physics of Hidden Particles
Collection Editors: Alexey S. Zhevlakov, Valery E. Lyubovitskij, Dmitry V. Kirpichnikov