Astroparticle Physics最新文献

{"title":"Atmospheric muons and their variations with temperature","authors":"S. Verpoest ,&nbsp;D. Soldin ,&nbsp;P. Desiati","doi":"10.1016/j.astropartphys.2024.102985","DOIUrl":"https://doi.org/10.1016/j.astropartphys.2024.102985","url":null,"abstract":"<div><p>Seasonal variations of atmospheric muons are traditionally interpreted in terms of an effective temperature that relates the atmospheric temperature profile at a given time to the dependence of muon production on atmospheric depth. This paper aims to review and generalize the treatment of muon production and effective temperature that has been used to interpret seasonal variations of atmospheric muons by many experiments. The formalism is developed both in integral form – for application to compact detectors at a fixed depth that record all muons with <span><math><mrow><msub><mrow><mi>E</mi></mrow><mrow><mi>μ</mi></mrow></msub><mo>&gt;</mo><msubsup><mrow><mi>E</mi></mrow><mrow><mi>μ</mi></mrow><mrow><mi>min</mi></mrow></msubsup></mrow></math></span> – and in differential form — for application to extended detectors like IceCube, KM3NeT, and Baikal-GVD, where the rates are proportional to energy-dependent effective areas.</p></div>","PeriodicalId":55439,"journal":{"name":"Astroparticle Physics","volume":"161 ","pages":"Article 102985"},"PeriodicalIF":3.5,"publicationDate":"2024-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140948741","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Loaded layer-cake model for cosmic ray interaction around exploding super-giant stars making black holes","authors":"M.L. Allen ,&nbsp;P.L. Biermann ,&nbsp;A. Chieffi ,&nbsp;D. Frekers ,&nbsp;L.Á. Gergely ,&nbsp;B. Harms ,&nbsp;I. Jaroschewski ,&nbsp;P.S. Joshi ,&nbsp;P.P. Kronberg ,&nbsp;E. Kun ,&nbsp;A. Meli ,&nbsp;E.-S. Seo ,&nbsp;T. Stanev","doi":"10.1016/j.astropartphys.2024.102976","DOIUrl":"https://doi.org/10.1016/j.astropartphys.2024.102976","url":null,"abstract":"&lt;div&gt;&lt;p&gt;The experiment AMS on the International Space-Station has produced accurate cosmic ray spectra for many chemical elements, both primaries like He, C, O, Fe, other cosmic ray (CR) primaries like Ne, Mg, and Si, secondaries like Li, Be, B, and of mixed provenance, like N, Na, and Al. The AMS spectra demonstrate that interaction is seriously diminishing fluxes up to a rigidity of about 100 GV, and so the existing models for CR interaction have to be re-examined. Based on earlier well-established ideas a model is proposed here that focusses on the cosmic ray interaction first in the wind shock shell of super giant stars, when the supernova driven shock races through, and second in the OB-Superbubble surrounding the SN: These stars include both red super-giant stars and blue super-giant stars; both produce black holes in their explosion, and drive winds and jets with electric currents. Variability of these winds or jets gives rise to temporary electric fields, as has recently been demonstrated, and discharge (so lightning) acceleration gives steep spectra, with synchrotron losses to &lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;p&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;−&lt;/mo&gt;&lt;mn&gt;5&lt;/mn&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt; in momentum &lt;span&gt;&lt;math&gt;&lt;mi&gt;p&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt;; these spectra are typically observed in both Galactic and some extragalactic radio filaments. Analogous hadron spectra &lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;p&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;−&lt;/mo&gt;&lt;mn&gt;4&lt;/mn&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt; excite a flat spectrum of magnetic irregularities in the bubble zone, which in turn yields a steep dependence of residence time versus energy, with power &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mo&gt;−&lt;/mo&gt;&lt;mspace&gt;&lt;/mspace&gt;&lt;mn&gt;5&lt;/mn&gt;&lt;mo&gt;/&lt;/mo&gt;&lt;mn&gt;3&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;. This spectrum is indicated by the AMS data and appears to be required to explain the CR spectra below 100 GV. The emphasis in this paper is to work out the interaction of the freshly accelerated cosmic ray particles. In the model presented here the interaction is derived as a function of time, and then integrated, or developed to long times. The model gives a rigidity dependence of the secondary/primary ratio of slope &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mo&gt;−&lt;/mo&gt;&lt;mspace&gt;&lt;/mspace&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;mo&gt;/&lt;/mo&gt;&lt;mn&gt;3&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; as well as the strong reduction of the primary fluxes below a rigidity of about 100 GV, relative to a power-law injection spectrum, with slope &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;mspace&gt;&lt;/mspace&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;. The two key aspects based on blue super-giant stars and a magnetic irregularity spectrum in the bubble zone given by lightning are (i) a much larger column of interaction, allowed because of heavy element enrichment of the interaction zone, and (ii) even He, C, and O may have a small secondary contribution, as the difference to the Fe spectrum suggests; this small secondary component is visible in the &lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;3&lt;/mn&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt;He/&lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;4&lt;/mn&gt;&lt;/mrow&gt;&lt;/msup&gt;","PeriodicalId":55439,"journal":{"name":"Astroparticle Physics","volume":"161 ","pages":"Article 102976"},"PeriodicalIF":3.5,"publicationDate":"2024-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140879410","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Some inflationary models under the light of Planck 2018 results","authors":"Daniel Pozo ,&nbsp;Jordan Zambrano ,&nbsp;Ismael Villegas ,&nbsp;Rafael Hernández–Jiménez ,&nbsp;Clara Rojas","doi":"10.1016/j.astropartphys.2024.102977","DOIUrl":"https://doi.org/10.1016/j.astropartphys.2024.102977","url":null,"abstract":"<div><p>In this work we study four well-known inflationary scenarios that are reported by the most recent Planck observations: Natural inflation, Hilltop quartic inflation, Starobinsky inflationary model, and Large field power-law potentials <span><math><mrow><mi>V</mi><mrow><mo>(</mo><mi>ϕ</mi><mo>)</mo></mrow><mo>∼</mo><msup><mrow><mi>ϕ</mi></mrow><mrow><mi>p</mi></mrow></msup></mrow></math></span>, considering <span><math><mrow><mi>p</mi><mo>=</mo><mfrac><mrow><mn>2</mn></mrow><mrow><mn>3</mn></mrow></mfrac><mo>,</mo><mfrac><mrow><mn>4</mn></mrow><mrow><mn>3</mn></mrow></mfrac></mrow></math></span>. The analysis is done using both the slow-roll approximation and the numerical solution to the background and perturbation equations. We show that the numerical solution improved the precision of these models with respect to the contour plot <span><math><mi>r</mi></math></span> vs. <span><math><msub><mrow><mi>n</mi></mrow><mrow><mi>S</mi></mrow></msub></math></span>, having a lower <span><math><mi>r</mi></math></span> in each model compared to the value calculated from the slow-roll approximation.</p></div>","PeriodicalId":55439,"journal":{"name":"Astroparticle Physics","volume":"161 ","pages":"Article 102977"},"PeriodicalIF":3.5,"publicationDate":"2024-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140816300","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On possible traversable wormhole solutions supported by Karmarkar condition in R2−gravity within the f(R,T)−formalism","authors":"Abdelghani Errehymy ,&nbsp;S.K. Maurya ,&nbsp;Gabriel-Eduard Vîlcu ,&nbsp;Meraj Ali Khan ,&nbsp;Mohammed Daoud","doi":"10.1016/j.astropartphys.2024.102972","DOIUrl":"https://doi.org/10.1016/j.astropartphys.2024.102972","url":null,"abstract":"<div><p>In their seminal work, Morris and Thorne (1988) introduced the concept of traversable wormholes (WHs), which are geometric structures serving as bridges to connect two distinct spacetimes or different points within the same spacetime. The properties of these WHs are determined by the choice of the shape function. Extensive research has been conducted in the literature on WHs within modified theories of gravity, considering various types of shape functions. In this paper, we focus on deriving the simplest solutions for traversable WHs within the framework of <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>R</mi><mo>,</mo><mi>T</mi><mo>)</mo></mrow></mrow></math></span> gravity. Our specific focus lies on the functional form <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>R</mi><mo>,</mo><mi>T</mi><mo>)</mo></mrow><mo>=</mo><mi>R</mi><mo>+</mo><mi>α</mi><msup><mrow><mi>R</mi></mrow><mrow><mn>2</mn></mrow></msup><mo>+</mo><mi>λ</mi><mi>T</mi></mrow></math></span>, where <span><math><mi>R</mi></math></span> represents the Ricci scalar and <span><math><mi>T</mi></math></span> denotes the trace of the energy–momentum tensor. By incorporating quadratic geometric and linear material corrections, we demonstrate that the matter content of WHs can obediently conform to the energy conditions (ECs). This study significantly advances our understanding of WHs within the context of modified gravity. Our findings shed new light on the behavior and properties of WHs, highlighting their compatibility with the <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>R</mi><mo>,</mo><mi>T</mi><mo>)</mo></mrow></mrow></math></span> gravity framework. By unveiling the ability of WHs to adhere to ECs through the inclusion of geometric and material corrections, we provide groundbreaking insights into these intriguing objects. Overall, our research contributes to the broader field of gravitational physics by presenting a unique perspective on WH modeling. By exploring WHs within the <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>R</mi><mo>,</mo><mi>T</mi><mo>)</mo></mrow></mrow></math></span> gravity framework and demonstrating their conformity to ECs, we expand our knowledge of these fascinating structures and pave the way for further investigations in this area.</p></div>","PeriodicalId":55439,"journal":{"name":"Astroparticle Physics","volume":"160 ","pages":"Article 102972"},"PeriodicalIF":3.5,"publicationDate":"2024-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140557892","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evidence of jet-caused 12-year optical periodicity of blazar OJ 287","authors":"Gorbachev M.A.,&nbsp;Butuzova M.S.,&nbsp;Nazarov S.V.,&nbsp;Zhovtan A.V.","doi":"10.1016/j.astropartphys.2024.102965","DOIUrl":"https://doi.org/10.1016/j.astropartphys.2024.102965","url":null,"abstract":"<div><p>Blazar OJ 287 is one of the first candidates with the assumed compact system of two supermassive black holes in the center. Orbital interaction in this system has been used to explain the for over a century light curve, in which optical flares are repeated with a quasi-period of 12 years and have almost yearly duration. The absence of the predicted flare in 2022 casts doubt on the dominant model of a close system of binary black holes. The detection of optical flares outside the 12-year period and their interpretation by processes in the jet complicates the construction of a complete picture of the blazar OJ 287 optical variability. Here, we analyze the 50-year evolution of the optical spectrum and prove that the changing coefficient of relativistic boosting of two regions in a helical jet subject to an age-long orientation change forms all flares. Our findings indicate the absence of the compact binary black hole system and the impossibility of drawing reliable conclusions about the central engine of active galactic nuclei based only on the quasi-periodic brightness variability of blazars.</p></div>","PeriodicalId":55439,"journal":{"name":"Astroparticle Physics","volume":"160 ","pages":"Article 102965"},"PeriodicalIF":3.5,"publicationDate":"2024-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140537132","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Thomas K. Gaisser, a pioneer of particle astrophysics","authors":"Francis Halzen ,&nbsp;Paolo Lipari","doi":"10.1016/j.astropartphys.2024.102963","DOIUrl":"https://doi.org/10.1016/j.astropartphys.2024.102963","url":null,"abstract":"<div><p>We describe the pioneering contributions of Thomas K. Gaisser to the birth and development of particle astrophysics, a new field of research at the intersection of cosmic ray physics, astronomy, astrophysics, and particle physics that has emerged in the last few decades. We will especially focus on his studies of natural beams of neutrinos: those generated by the interactions of cosmic rays in the Earth’s atmosphere and those emitted by astrophysical sources. Tom actively participated in the discovery of these cosmic neutrinos as well. His contributions also extend to gamma-ray astronomy, the study of the cosmic ray spectra and composition, and the modeling of cosmic ray interactions in the atmosphere and in astrophysical environments. Tom invariably focused his research on the theoretical and phenomenological problems of greatest interest at the time, producing frameworks that transparently interpreted often complex data. These studies have been very influential and have shaped the development of the field.</p></div>","PeriodicalId":55439,"journal":{"name":"Astroparticle Physics","volume":"159 ","pages":"Article 102963"},"PeriodicalIF":3.5,"publicationDate":"2024-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140320808","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sibyll★","authors":"Felix Riehn ,&nbsp;Anatoli Fedynitch ,&nbsp;Ralph Engel","doi":"10.1016/j.astropartphys.2024.102964","DOIUrl":"https://doi.org/10.1016/j.astropartphys.2024.102964","url":null,"abstract":"<div><p>In the last decade, an increasing number of datasets have revealed a consistent discrepancy between the number of muons measured in ultra-high-energy extensive air showers (EAS) and the numbers predicted by simulations. This gap persists despite incorporating Large Hadron Collider (LHC) data into the tuning of current hadronic interaction models, leading to the phenomenon often termed the “muon puzzle”. To gain a deeper understanding of the potential origins of this muon puzzle, we have developed Sibyll<span><math><msup><mrow></mrow><mrow><mo>★</mo></mrow></msup></math></span>, a series of phenomenologically modified versions of Sibyll 2.3d. In these models, we have increased muon production by altering <span><math><msup><mrow><mi>ρ</mi></mrow><mrow><mn>0</mn></mrow></msup></math></span>, baryon–antibaryon pair, or kaon production in hadronic multiparticle production processes. These variants remain within bounds from provided by accelerator measurements, including those from the LHC and fixed-target experiments, notably NA49 and NA61, showing a level of consistency comparable to Sibyll 2.3d. Our findings show that these modifications can increase the muon count in EAS by up to 35%, while minimally affecting the depth of shower maximum (<span><math><msub><mrow><mi>X</mi></mrow><mrow><mi>max</mi></mrow></msub></math></span>) and other shower variables. Additionally, we assess the impact of these modifications on various observables, including inclusive muon and neutrino fluxes and the multiplicities of muon bundles in deep underground and water/ice Cherenkov detectors. We aim for at least one of these model variants to offer a more accurate representation of EAS data at the highest energies, thereby enhancing the quality of Monte Carlo predictions used in training neural networks. This improvement is crucial for achieving more reliable data analyses and interpretations.</p></div>","PeriodicalId":55439,"journal":{"name":"Astroparticle Physics","volume":"160 ","pages":"Article 102964"},"PeriodicalIF":3.5,"publicationDate":"2024-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140348008","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Observations of the Crab Nebula with MACE (Major Atmospheric Cherenkov Experiment)","authors":"Borwankar C. ,&nbsp;Sharma M. ,&nbsp;Hariharan J. ,&nbsp;Venugopal K. ,&nbsp;Godambe S. ,&nbsp;Mankuzhyil N. ,&nbsp;Chandra P. ,&nbsp;Khurana M. ,&nbsp;Pathania A. ,&nbsp;Chouhan N. ,&nbsp;Dhar V.K. ,&nbsp;Thubstan R. ,&nbsp;Norlha S. ,&nbsp;Keshavanand ,&nbsp;Sarkar D. ,&nbsp;Dar Z.A. ,&nbsp;Kotwal S.V. ,&nbsp;Godiyal S. ,&nbsp;Kushwaha C.P. ,&nbsp;Singh K.K. ,&nbsp;Yadav K.K.","doi":"10.1016/j.astropartphys.2024.102960","DOIUrl":"10.1016/j.astropartphys.2024.102960","url":null,"abstract":"<div><p>The Major Atmospheric Cherenkov Experiment (MACE) is a large size (21 m) Imaging Atmospheric Cherenkov Telescope (IACT) installed at an altitude of 4270 m above sea level at Hanle, Ladakh in northern India. Here we report the detection of Very High Energy (VHE) <span><math><mi>γ</mi></math></span>-ray emission from Crab Nebula above 80 GeV. We analyzed <span><math><mo>∼</mo></math></span> 15 h of data collected at low zenith angle between November 2022 and February 2023. The energy spectrum is well described by a log-parabola function with a flux of <span><math><mrow><mo>∼</mo><mrow><mo>(</mo><mn>3</mn><mo>.</mo><mn>46</mn><mo>±</mo><mn>0</mn><mo>.</mo><mn>2</mn><msub><mrow><mn>6</mn></mrow><mrow><mi>s</mi><mi>t</mi><mi>a</mi><mi>t</mi></mrow></msub><mo>)</mo></mrow><mo>×</mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mo>−</mo><mn>10</mn></mrow></msup></mrow></math></span> <span><math><mrow><msup><mrow><mi>TeV</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup><msup><mrow><mi>cm</mi></mrow><mrow><mo>−</mo><mn>2</mn></mrow></msup><msup><mrow><mi>s</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math></span>, at 400 GeV with spectral index of <span><math><mrow><mn>2</mn><mo>.</mo><mn>09</mn><mo>±</mo><mn>0</mn><mo>.</mo><mn>0</mn><msub><mrow><mn>6</mn></mrow><mrow><mi>s</mi><mi>t</mi><mi>a</mi><mi>t</mi></mrow></msub></mrow></math></span> and a curvature parameter of <span><math><mrow><mn>0</mn><mo>.</mo><mn>08</mn><mo>±</mo><mn>0</mn><mo>.</mo><mn>0</mn><msub><mrow><mn>7</mn></mrow><mrow><mi>s</mi><mi>t</mi><mi>a</mi><mi>t</mi></mrow></msub></mrow></math></span>. The <span><math><mi>γ</mi></math></span>-rays are detected in an energy range spanning from 80<!--> <!-->GeV to <span><math><mo>∼</mo></math></span>5<!--> <!-->TeV. The energy resolution improves from <span><math><mo>∼</mo></math></span> 34% at an analysis energy threshold of 80<!--> <!-->GeV to <span><math><mo>∼</mo></math></span> 21% above 1<!--> <!-->TeV. The daily light curve and the spectral energy distribution obtained for the Crab Nebula is in agreement with previous measurements, considering statistical and systematic uncertainties.</p></div>","PeriodicalId":55439,"journal":{"name":"Astroparticle Physics","volume":"159 ","pages":"Article 102960"},"PeriodicalIF":3.5,"publicationDate":"2024-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140282874","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Curvature Quantization based on the Ehrenfest Paradox in the Bohr Atomic Model","authors":"Fima Ardianto Putra ,&nbsp;Ahmad Khalil Yaqubi ,&nbsp;Riza Ibnu Adam ,&nbsp;Vandan Wiliyanti ,&nbsp;Puzi Anigrahawati","doi":"10.1016/j.astropartphys.2024.102950","DOIUrl":"10.1016/j.astropartphys.2024.102950","url":null,"abstract":"<div><p>Ehrenfest Paradox has been studied in the Bohr Atomic Model as a theoretical procedure for expressing the atomic coordinate curvature in the term of electromagnetic fine structure/coupling constant α = 1/137. The strength of the curvature corresponding to the gravitational aspect depends on the principal quantum number via a new constant <span><math><mrow><mfrac><mrow><mn>16</mn><msup><mrow><mi>α</mi></mrow><mn>2</mn></msup></mrow><msubsup><mi>a</mi><mn>0</mn><mn>2</mn></msubsup></mfrac><mo>=</mo><mn>3</mn><mo>,</mo><mn>0348</mn><mspace></mspace><mo>×</mo><msup><mrow><mn>10</mn></mrow><mn>17</mn></msup><msup><mrow><mi>m</mi></mrow><mrow><mo>−</mo><mn>2</mn></mrow></msup></mrow></math></span>, which shows that the value of the curvature is quantised. For instance <em>n</em> = 1, the value is 3, 0349  × 10¹⁷ <em>m</em>⁻². The curvature value in the Bohr atomic model can be used as a standard to compare how strong the curvatures of all systems are. This procedure can also be generalized to the strong and weak interactions in such a way that the value of the curvature can be represented by their own coupling constants. In the real situation, we can take the case of the atom near supermassive objects such as: blackhole, neutron star, white dwarf, etc. In this case, the atom is in the curved space-time, while the space-time curvature is quantized by the atom. Principally, the idea of the curvature and quantization are correlated. The excitation (the change of the state) of the atom or the atomic nuclei will generate the change of the space-time curvature Δ<em>G</em>_μν(α)_<em>n</em> that manifests a quantized curvature propagation (curvaton) through the space-time coordinate in the form of quantum stress tensor <span><math><mrow><mstyle><mi>Δ</mi></mstyle><msubsup><mi>T</mi><mrow><mi>μ</mi><mi>ν</mi></mrow><mrow><mo>(</mo><mrow><mi>q</mi><mn>2</mn><mi>B</mi></mrow><mo>)</mo></mrow></msubsup><mo>=</mo><mi>ℏ</mi><mstyle><mi>Δ</mi></mstyle><msub><mi>σ</mi><mi>n</mi></msub><mstyle><mi>Δ</mi></mstyle><msub><mi>G</mi><mrow><mi>μ</mi><mi>ν</mi></mrow></msub><msub><mrow><mo>(</mo><mi>α</mi><mo>)</mo></mrow><mi>n</mi></msub></mrow></math></span>. It can be viewed as a unit of moving curvature reduced to a gravitational wave. This theory can be considered to expand the unification between quantum mechanics and gravitation.</p></div>","PeriodicalId":55439,"journal":{"name":"Astroparticle Physics","volume":"159 ","pages":"Article 102950"},"PeriodicalIF":3.5,"publicationDate":"2024-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140149663","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The exact solution approach to warm inflation","authors":"Oem Trivedi","doi":"10.1016/j.astropartphys.2024.102951","DOIUrl":"https://doi.org/10.1016/j.astropartphys.2024.102951","url":null,"abstract":"<div><p>The theory of cosmic inflation has received a great amount of deserved attention in recent years due to it’s stunning predictions about the early universe. Alongside the usual cold inflation paradigm, warm inflation has garnered a huge amount of interest in modern inflationary studies. It’s peculiar features and specifically different predictions from cold inflation have led to a substantial amount of literature about it. Various modified cosmological scenarios have also been studied in the warm inflationary regime. In this work, we introduce the exact solution approach for warm inflation. This approach allows one to directly study warm inflationary regime in a variety of modified cosmological scenarios. We begin by outlining our method and show that it generalizes the modified Friedmann approach of Del Campo, and reduces to the well known Hamilton–Jacobi formalism for inflation in particular limits. We also find the perturbation spectra for cosmological and tensor perturbations in the early universe, and then apply our method to study warm inflation in a Tsallis entropy modified Friedmann universe. We end our paper with some concluding remarks on the domain of applicability of our work.</p></div>","PeriodicalId":55439,"journal":{"name":"Astroparticle Physics","volume":"158 ","pages":"Article 102951"},"PeriodicalIF":3.5,"publicationDate":"2024-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140024007","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}