Modern Physics Research Articles

The Dirac equation as a linear tensor equation for one component

The Dirac equation is one of the most fundamental equations of modern physics. It is a spinor equation, but some tensor equivalents of the equation were proposed previously. Those equivalents were either nonlinear or involved several components of the Dirac field. On the other hand, the author showed previously that the Dirac equation in electromagnetic field is equivalent to a fourth-order equation for one component of the Dirac spinor. The equivalency is used in this work to derive a linear tensor equivalent of the Dirac equation for just one component. This surprising result can be used in applications of the Dirac equation, for example, in general relativity or for lattice approximation of the Dirac field, and can improve our understanding of the Dirac equation.

Strongly correlated multielectron bunches from interaction with quantum light.

Strongly correlated electron systems are a cornerstone of modern physics, being responsible for groundbreaking phenomena from superconducting magnets to quantum computing. In most cases, correlations in electrons arise exclusively because of Coulomb interactions. In this work, we reveal that free electrons interacting simultaneously with a light field can become highly correlated via mechanisms beyond Coulomb interactions. In the case of two electrons, the resulting Pearson correlation coefficient for the joint probability distribution of the output electron energies is enhanced by more than 13 orders of magnitude compared to that of electrons interacting with the light field in succession (one after another). These highly correlated electrons are the result of momentum and energy exchange between the participating electrons via the external quantum light field. Our findings pave the way to the creation and control of highly correlated free electrons for applications including quantum information and ultrafast imaging.

Breaking and resurgence of symmetry in the non-Hermitian Su-Schrieffer-Heeger model in photonic waveguides

Symmetry is one of the cornerstones of modern physics and has profound implications in different areas. In symmetry-protected topological systems, symmetries are responsible for protecting surface states, which are at the heart of the fascinating properties exhibited by these materials. When the symmetry protecting the edge mode is broken, the topological phase becomes trivial. By engineering losses that break the symmetry protecting a topological Hermitian phase, we show that a new genuinely non-Hermitian symmetry emerges, which protects and selects one of the boundary modes: the topological monomode. Moreover, the topology of the non-Hermitian system can be characterized by an effective Hermitian Hamiltonian in a higher dimension. To corroborate the theory, we experimentally investigated the non-Hermitian one- and two-dimensional SSH models using photonic lattices and observed dynamically generated monomodes in both cases. We classify the systems in terms of the (non-Hermitian) symmetries that are present and calculate the corresponding topological invariants. Published by the American Physical Society 2024

Virtual experiment on platonic solids for teaching space-time quantization

The work presents the virtual experiment on Platonic solids in a complementary way, where its importance is crucially used for the treatment of the teaching of the quantization of space-time via loop quantum gravity. The research was part of one of the studies carried out with 23 students in the 3rd year of high school in São Cristóvão, Rio de Janeiro, Brazil. The project is part of several introduced subjects on modern and contemporary physics, as well as frontier research topics. The student starts to have a student-researcher posture and based on Ausubel and Bruner's learning theories, they develop significant learning and receive new information and concepts at the elementary level, conditioning them to a critical and reflective posture. We use the experiment in which students interactively learn three-dimensional shapes, calculate surface area and volume and discover mathematical properties of shapes, necessary knowledge that covers the discussion of the theory. Subsequently, they carried out the skills test and we collected data from the students' operations to present the scenario of innovation and reflection on the possibility of introducing research topics in physics, but with appropriate language for the audience of interest according to Bruner's learning theory.

HighNESS conceptual design report: Volume II. The NNBAR experiment.

A key aim of the HighNESS project for the European Spallation Source is to enable cutting-edge particle physics experiments. This volume presents a conceptual design report for the NNBAR experiment. NNBAR would exploit a new cold lower moderator to make the first search in over thirty years for free neutrons converting to anti-neutrons. The observation of such a baryon-number-violating signature would be of fundamental significance and tackle open questions in modern physics, including the origin of the matter-antimatter asymmetry. This report shows the design of the beamline, supermirror focusing system, magnetic and radiation shielding, and anti-neutron detector necessary for the experiment. A range of simulation programs are employed to quantify the performance of the experiment and show how background can be suppressed. For a search with full background suppression, a sensitivity improvement of three orders of magnitude is expected, as compared with the previous search. Civil engineering studies for the NNBAR beamline are also shown, as is a costing model for the experiment.

Analysis of the strong decays of SU(3) partners of the $\Omega(2012)$ baryon

Abstract We estimate the coupling constants and decay widths of the $SU(3)$ partners of the $\Omega(2012)$ hyperon, as discovered by the BELLE Collaboration, using the distribution amplitudes of the octet baryons within light cone sum rules method. Our study includes a comparison of the obtained results for the relevant decay widths with those derived within the framework of the flavor $SU(3)$ analysis. We observe a good agreement between the predictions of both approaches. Moreover, our results on the decay width of the $\Omega \to \Xi K$ is compatible with the existing experimental result within the uncertainties of the model predictions. These results can provide helpful insights for determining the nature of the $SU(3)$ partners of the $\Omega(2012)$ baryon. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Article funded by SCOAP3 and published under licence by Chinese Physical Society and the Institute of High Energy Physics of the Chinese Academy of Science and the Institute of Modern Physics of the Chinese Academy of Sciences and IOP Publishing Ltd.

Learning Problems of Prospective Teachers in Lectures Modern Physics During the Covid-19 Pandemic

Since the COVID-19 pandemic hit the world, many problems have been caused by accompanying effects, including impacts in the field of education. This study aims to explore the problems faced by physics education study program students in modern physics lectures in online learning during the COVID-19 pandemic. The method used in this study is a qualitative description with a questionnaire as a data collection technique. A total of 28 students who contracted modern physics courses and two lecturers who taught modern physics courses were participants in this study. The collected data were analyzed descriptively-qualitatively. After data analysis, several problems faced by students in attending modern physics lectures can be identified, namely: difficulty mastering concepts, internet signal interference, less interesting/monotonous learning, and never doing modern physics practicum. Limited tools are the main factor in the inability to carry out practicum. Even though practicum allows students to master abstract concepts of modern physics. Based on these findings, further research can be carried out that can facilitate students to more easily master modern physics concepts that are integrated with a practicum in the learning process. Keywords: learning problems, prospective teachers, lectures modern physics, covid-19 pandemic

A 21st Century MONADOLOGY or Principles of Philosophy

This work presents a recasting and tribute to Gottfried Wilhelm Leibniz’s 1714 text, known as the Monadology_,_ on its 300th anniversary (first released in 2014 with some revisions in 2024), analysing it from a 21st century philosophical and scientific perspective. Leibniz’s monads are reinterpreted as indivisible dynamic modes of action as described by modern physics. His key insights regarding the relational and perspectival nature of reality, and the distinction between the telic causation of indivisible entities vs the efficient causation of aggregates, are highlighted as prescient of quantum physics and the correspondence principle. The practical biological application of his ideas requires updating, but even there, he shows some remarkably forward-looking thoughts. The traditional concept of an immortal human soul is replaced by an audience of ephemeral cellular “listeners” that apperceive the living story of a person. Leibniz’s principles are seen to contain powerful and still relevant insights into the nature of physical reality, human knowledge and ethics, meriting further exploration in light of contemporary science. In summary, while specific aspects of Leibniz’s synthesis require updating, his core logical principles and global vision retain surprising relevance and potential for reframing our understanding.

Calibration of the Cryogenic Measurement System of a Resonant Haloscope Cavity

Abstract Possible light bosonic dark matter interactions with the Standard Model photon have been searched by microwave resonant cavities. In this paper, we demonstrate the cryogenic readout system calibration of a 7.138 GHz copper cavity with a loaded quality factor $Q_l=10^4$, operated at 22 mK temperature based on a dilution refrigerator. Our readout system consists of High Electron Mobility Transistors as cryogenic amplifiers at 4 K, plus room-temperature amplifiers and a spectrum analyzer for signal power detection. We test the system with a superconducting two-level system as a single-photon source in the microwave frequency regime and report an overall 95.6 dB system gain and -71.4 dB attenuation in the cavity's input channel. The effective noise temperature of the measurement system is 7.5 K. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Article funded by SCOAP3 and published under licence by Chinese Physical Society and the Institute of High Energy Physics of the Chinese Academy of Science and the Institute of Modern Physics of the Chinese Academy of Sciences and IOP Publishing Ltd.

A 95 GeV light Higgs in the top-pair-associated diphoton channel at the LHC in the Minimal Dilaton Model

Abstract Motivated by experimental hints and theoretical frameworks indicating the existence of an extended Higgs sector, we undertake a study to explore the feasibility of detecting a 95 GeV light Higgs boson decaying into diphoton within the Minimal Dilaton Model (MDM) at the 14 TeV LHC. Initially, we identify the correlations between the production cross section, decay branching ratios, and model parameters, e.g., the scalar mixing angle $\sin\theta_S$. Subsequently, we utilize Monte Carlo simulations to generate the signal of the light Higgs boson via the process $pp \to t\bar{t}(s\to \gamma\gamma)$, along with the corresponding backgrounds. To effectively separate the signal from the dominant backgrounds $tt\gamma\gamma$, we employ a meticulous cut-based selection process. Ultimately, we find that with an integrated luminosity of $L = 3000 \fbm$, the regions of $|\sin\theta_S|>0.2$ can be covered at over a $3\sigma$ level. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Article funded by SCOAP3 and published under licence by Chinese Physical Society and the Institute of High Energy Physics of the Chinese Academy of Science and the Institute of Modern Physics of the Chinese Academy of Sciences and IOP Publishing Ltd.

Space, Gravity-Time

Space and time, from Newton's point of view, were considered as two separate and absolute concepts, and gravity was also defined as a force that varies according to the mass of two objects and their distance from each other. However, Hermann Minkowski, using Einstein's theory of relativity, offered a geometric interpretation of special relativity, integrating time and the three dimensions of space into a unified four-dimensional model now known as Minkowski space. In the theory of general relativity, gravity is also defined as a geometric function and a consequence of the curvature of space-time, which itself arises from the uneven distribution of mass and energy. One of the key outcomes of the theory of general relativity is that the motion of celestial bodies orbiting around other bodies in curved paths is not driven by a force known as gravity. Instead, bodies are actually following the closest objects to them through curved space-time, a bending that gravity is a result of. This movement happens along the shortest path, known as a geodesic. In contrast to Newton's view, the theory of relativity has shown that the speed at which gravity acts is limited to the speed of light. Modern physics proposes that this transmission of gravity might be carried out by hypothetical particles called gravitons. Another prediction of this theory is the concept of a gravitational potential well, which explains why the frequency of light increases or decreases as it falls into or escapes from this well, due to the curvature of space-time caused by a massive object. Time dilation near a massive object is also a phenomenon that occurs due to the strong gravitational field of that object. In this regard, Einstein's theory of special relativity explains how the laws of physics are the same for all observers moving at the same velocity and how the speed of light is constant in a vacuum. One of the consequences of this theory is that mass and energy are considered equivalent and interchangeable according to the famous E=mc2 equation. However, in the theories of T-Consciousness Cosmology, space is conceptualized independently and as a principle, in the form of a mesh, and time is described as an entropic force that acts opposite to gravity to break down objects that cause space to contract. In other words, the entropic force of time is introduced as a force that arises from mass to release space from stress, not as a fourth dimension perpendicular to the dimensions of space. Furthermore, this perspective considers varying viscosities for the space surrounding celestial objects. It introduces gravity as a force that is equivalent to the viscosity of space, rather than as a consequence of curved geometry, as typically presented in relativity. Gravity functions in accordance with the structure of space mesh. Consequently, phenomena such as gravitational redshift or blueshift are interpreted as outcomes of the viscosity of space. This perspective states that as light enters black holes, the mass-energy equivalence principle is violated because of the energetic resonance of the wave during its gravitational blackshift; implying that black holes are matter production factories. Furthermore, the mass-energy equivalence principle and the law of conservation of matter and energy do not hold true in the Cosmic Black Hole, which is the beginning of the cosmos, or after the final stage of space Rebound.

Deep learning-based spatiotemporal multi-event reconstruction for delay line detectors

Accurate observation of two or more particles within a very narrow time window has always been a challenge in modern physics. It creates the possibility of correlation experiments, such as the ground-breaking Hanbury Brown–Twiss experiment, leading to new physical insights. For low-energy electrons, one possibility is to use a Microchannel plate with subsequent delay lines for the readout of the incident particle hits, a setup called a Delay Line Detector. The spatial and temporal coordinates of more than one particle can be fully reconstructed outside a region called the dead radius. For interesting events, where two electrons are close in space and time, the determination of the individual positions of the electrons requires elaborate peak finding algorithms. While classical methods work well with single particle hits, they fail to identify and reconstruct events caused by multiple nearby particles. To address this challenge, we present a new spatiotemporal machine learning model to identify and reconstruct the position and time of such multi-hit particle signals. This model achieves a much better resolution for nearby particle hits compared to the classical approach, removing some of the artifacts and reducing the dead radius a factor of eight. We show that machine learning models can be effective in improving the spatiotemporal performance of delay line detectors.

Detecting Neutrinos from Supernova Bursts in PandaX-4T

Abstract Neutrinos from core-collapse supernovae are essential for the understanding of neutrino physics and stellar evolution. The dual-phase xenon dark matter detectors can provide a way to track explosions of galactic supernovae by detecting neutrinos through coherent elastic neutrino-nucleus scatterings. In this study, a variation of progenitor masses as well as explosion models are assumed to predict the neutrino fluxes and spectra, which result in the number of expected neutrino events ranging from 6.6 to 13.7 at a distance of 10 kpc over a 10-second duration with negligible backgrounds at PandaX-4T. Two specialized triggering alarms for monitoring supernova burst neutrinos are built. The efficiency of detecting supernova explosions at various distances in the Milky Way is estimated. These alarms will be implemented in the real-time supernova monitoring system at PandaX-4T in the near future, providing the astronomical communities with supernova early warnings. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Article funded by SCOAP3 and published under licence by Chinese Physical Society and the Institute of High Energy Physics of the Chinese Academy of Science and the Institute of Modern Physics of the Chinese Academy of Sciences and IOP Publishing Ltd.

Prospects to study hyperon-nucleon interactions at BESIII

Abstract The prospects to study hyperon-nuclei/nucleon interactions at BESIII and similar $e^+ e^-$ colliders are proposed in this work. Utilizing the large quantity of hyperons produced by the decay of 10 billion $J/\psi$ and 2.7 billion $\psi(3686)$ collected at BESIII, the cross sections of several specific elastic or inelastic hyperon-nuclei reactions can be measured via the scattering between the hyperons and the nucleus in the dense objects of BESIII detector. Subsequently, the cross sections of corresponding hyperon-nucleon interactions are able to be extracted with further phenomenological calculation. Furthermore, the interactions between antihyperon and nuclei/nucleon, including scattering and annihilation, can also be studied via the method proposed in this paper. The results will definitely benefit a lot the precise probe of the hyperon-nuclei/nucleon interactions and provide constraints for the studies of the potential of strong interaction, the origin of color confinement, the unified model for baryon-baryon interactions, and the internal structure of neutron stars. In addition, the desirable prospects of corresponding studies in the future Super Tau-Charm Factory (STCF) are discussed and estimated in this work. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Article funded by SCOAP3 and published under licence by Chinese Physical Society and the Institute of High Energy Physics of the Chinese Academy of Science and the Institute of Modern Physics of the Chinese Academy of Sciences and IOP Publishing Ltd.

Masses of the conjectured H-dibaryon at different temperatures

Abstract We present a lattice QCD determination of masses of the conjectured H-dibaryon $m_H$ at nine different temperatures
 $T/T_c =0.24, 0.63, 0.76, 0.84, 0.95, 1.09, 1.27, 1.52, 1.90$. In the meantime, the masses of baryon $N$, $\Sigma$, $\Xi$ and $\Lambda$ at different temperatures
 are also computed.
 The simulation is performed on anisotropic lattice with $N_f=2+1$ flavours of clover fermion at quark mass
 which corresponds to $m_\pi=384(4) {\rm MeV} $. The thermal ensembles were provided by the FASTSUM
 collaboration and the zero temperature ensembles by the Hadspec collaboration. We also calculate the spectral density of the correlation function of those particles.
 The spectral density distributions show rich peak structure at the lowest temperature, while at intermediate temperatures, the mass values of those particles obtained by extrapolation method reflect a two-peak structure.
 While the spectral density for octet baryon becomes smooth at $T/T_c = 1.27, 1.52, 1.90$, the spectral density for H-dibaryon becoms smooth at $T/T_c = 1.90$.
 At $T/T_c =0.24 $, the mass difference of H-dibaryon
 and
 $\Lambda$ pair $\Delta m = m_H - 2\,m_{\Lambda} $ is estimated to be $\Delta m = -14.6(6.2) {\rm MeV}$ which suggests there exists a bound H-dibaryon state. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Article funded by SCOAP3 and published under licence by Chinese Physical Society and the Institute of High Energy Physics of the Chinese Academy of Science and the Institute of Modern Physics of the Chinese Academy of Sciences and IOP Publishing Ltd.

Amplitude Analysis of the Decays D0→π+π-π+π- and π+π-π0π0

Abstract Using e+e- annihilation data corresponding to an integrated luminosity of 2.93 fb-1 taken at the center-of-mass energy √s=3.773 GeV with the BESIII detector, a joint amplitude analysis is performed on the decays D0→π+π-π+π- and D0→π+π-π0π0(non-η). The fit fractions of individual components are obtained, and large interferences among the dominant components of the decays D0→a1(1260)π, D0→π(1300)π, D0→ρ(770)ρ(770) and D0→2(ππ)S are found in both channels. With the obtained amplitude model, the CP-even fractions of D0→π+π-π+π- and D0→π+π-π0π0(non-η) are determined to be (75.2 ± 1.1stat. ± 1.5syst.)% and (68.9 ± 1.5stat. ± 2.4syst.)%, respectively. The branching fractions of D0→π+π-π+π- and D0→π+π-π0π0(non-η) are measured to be (0.688 ± 0.010stat. ± 0.010syst.)% and (0.951 ± 0.025stat. ± 0.021syst.)%, respectively. The amplitude analysis provides an important model for binning strategy in the measurements of the strong phase parameters of D0→4π when used to determine the CKM angle γ(Φ3) via the B-→DK- decay. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Article funded by SCOAP3 and published under licence by Chinese Physical Society and the Institute of High Energy Physics of the Chinese Academy of Science and the Institute of Modern Physics of the Chinese Academy of Sciences and IOP Publishing Ltd.

Microscopic ensemble bootstrap in phase space

Abstract The bootstrap method which has been studied under many quantum mechanical models turns out feasible in microcanonical ensemble as well. While the approach in [Y. Nakayama, Modern Physics Letters A 37, 10.1142/s0217732322500547 (2022)] produces a sector when energy is negative, in this paper we report a method that has stronger constraints and results in a smaller region. We also study other models to demonstrate the effectiveness of our method.

From Spherical Cows to Schrödinger’s Cat: what students want to learn in physics

This paper reflects on feedback received from 161 Ontario grade 12 physics students between 2017–2018 and 2020–2023, on the content and delivery in different modes (face-to-face, online, hybrid) of the 2008 Ontario Grade 12 Physics—University Preparation course (SPH4U). Across modes, students considered Revolutions in Modern Physics significantly more interesting and less stressful than any of the other four units. Students also identified Dynamics as significantly less interesting than all of the units, and found it significantly more stressful than all units other than Fields. Students were most interested in topics not previously studied (e.g. Special Theory of Relativity) that they felt promoted new ways of thinking. Adjusting to grade 12 expectations combined with more challenging course concepts were the primary contributors of stress. Included is a discussion of physics education reform, and the role of physics education in science, technology, engineering and mathematics.

On some novel solitonic structures for the Zhiber–Shabat model in modern physics

Abstract In this article, the modified Kudryashov and extended simple equation methods are employed to obtain analytical solutions for the Zhiber–Shabat problem. The outcomes of this study clearly indicate that the provided methodologies are appropriate techniques for generating some new exact solutions for nonlinear evolution equations. Furthermore, the nature of the solutions would be presented in three dimensions for various parameters applying the most advanced scientific instruments. The physical behavior of the solutions are graphically displayed, and it is established that the acquired solutions are newly constructed in the form of bright, dark, optical, singular, and bell-shaped periodic soliton wave structures. The properties of the nonlinear model have been illustrated using 3D, 2D, and contour plots by selecting an appropriate set of parameters, which is demonstrated to visualize the physical structures more productively. Finally, it is concluded that similar strategies can also be implemented to study many contemporary models. To the best of our knowledge, the current work presents a novel case study that has not been previously studied in order to generate several new solutions to the governing model appearing in diverse disciplines. The results show that the strategies that have been employed are more effective and capable than the traditional methods found in previous research.

Quantum Bullshit: How to Ruin Your Life With Advice From Quantum Physics & Farewell to Reality: How Modern Physics Has Betrayed The Search for Scientific Truth

Two reviews of two books. Title to be changed.