Pub Date : 2025-02-01DOI: 10.1016/j.physletb.2025.139265
G.G.L. Nashed
In this study, we introduce a toroidal solution for charged anti-de Sitter black holes in N dimensions within the framework of the quadratic form of gravity, employing the coincident gauge condition [1]. We assume to take the form , where . These black hole solutions are characterized by flat or cylindrical horizons. A notable feature of these solutions is the presence of both electric monopole and quadrupole components in the potential field. These monopole and quadrupole components are inseparable and exhibit interconnected momenta, distinguishing them from the known charged solutions in the linear case of non-metricity theory. Furthermore, we demonstrate that the curvature singularities of these solutions are less severe than those in charged general relativity solutions. Finally, we calculate thermodynamic parameters, including entropy, Hawking temperature, and Gibbs free energy. These calculations confirm the stability of our model.
{"title":"Special N-dimensional charged anti-de-Sitter black holes in f(Q) gravitational theory","authors":"G.G.L. Nashed","doi":"10.1016/j.physletb.2025.139265","DOIUrl":"10.1016/j.physletb.2025.139265","url":null,"abstract":"<div><div>In this study, we introduce a toroidal solution for charged anti-de Sitter black holes in <em>N</em> dimensions within the framework of the quadratic form of <span><math><mi>f</mi><mo>(</mo><mi>Q</mi><mo>)</mo></math></span> gravity, employing the coincident gauge condition <span><span>[1]</span></span>. We assume <span><math><mi>f</mi><mo>(</mo><mi>Q</mi><mo>)</mo></math></span> to take the form <span><math><mi>f</mi><mo>(</mo><mi>Q</mi><mo>)</mo><mo>=</mo><mi>Q</mi><mo>+</mo><mfrac><mrow><mn>1</mn></mrow><mrow><mn>2</mn></mrow></mfrac><mi>α</mi><msup><mrow><mi>Q</mi></mrow><mrow><mn>2</mn></mrow></msup><mo>−</mo><mn>2</mn><mi>Λ</mi></math></span>, where <span><math><mi>N</mi><mo>≥</mo><mn>4</mn></math></span>. These black hole solutions are characterized by flat or cylindrical horizons. A notable feature of these solutions is the presence of both electric monopole and quadrupole components in the potential field. These monopole and quadrupole components are inseparable and exhibit interconnected momenta, distinguishing them from the known charged solutions in the linear case of non-metricity theory. Furthermore, we demonstrate that the curvature singularities of these solutions are less severe than those in charged general relativity solutions. Finally, we calculate thermodynamic parameters, including entropy, Hawking temperature, and Gibbs free energy. These calculations confirm the stability of our model.</div></div>","PeriodicalId":20162,"journal":{"name":"Physics Letters B","volume":"861 ","pages":"Article 139265"},"PeriodicalIF":4.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143035210","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01DOI: 10.1016/j.physletb.2025.139263
Prudhvi N. Bhattiprolu, James D. Wells
We argue that a measurement of the Higgs boson self-coupling becomes particularly meaningful in a large and important class of theories when its sensitivity is within 40% of its Standard Model value. This constitutes a target for a future impactful experimental achievement. It is derived from recently obtained results of how extreme the differences can be between effective field theory operator coefficients when their origins are from reasonable custodial-violating theories beyond the Standard Model.
{"title":"A sensitivity target for an impactful Higgs boson self coupling measurement","authors":"Prudhvi N. Bhattiprolu, James D. Wells","doi":"10.1016/j.physletb.2025.139263","DOIUrl":"10.1016/j.physletb.2025.139263","url":null,"abstract":"<div><div>We argue that a measurement of the Higgs boson self-coupling becomes particularly meaningful in a large and important class of theories when its sensitivity is within 40% of its Standard Model value. This constitutes a target for a future impactful experimental achievement. It is derived from recently obtained results of how extreme the differences can be between effective field theory operator coefficients when their origins are from reasonable custodial-violating theories beyond the Standard Model.</div></div>","PeriodicalId":20162,"journal":{"name":"Physics Letters B","volume":"861 ","pages":"Article 139263"},"PeriodicalIF":4.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143035237","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01DOI: 10.1016/j.physletb.2025.139261
Subhasis Nalui, Subhra Bhattacharya
In this work we investigate the effect of complexity factor on the formation of photon spheres for spherically symmetric compact objects. The complexity factor obtained from the orthogonal splitting of the Riemann curvature tensor connects the geometric attributes of a compact spherically symmetric gravitating object with its matter inhomogeneity and pressure anisotropy via a scalar term. The novelty of the complexity factor is the inherent simple definition that identifies the evolution of matter tensors inside a given region of space-time. Such identification helps to obtain an equivalence class of gravitating compact objects based on their degree of complexity with zero complexity identified as the simplest system. On the other hand shadows and photon rings have become essential for identifying compact regions of space time characterised by massive gravity. Advanced observational data analysis tools augments the hope for identification of exotic gravitational objects, like the so called “black hole mimickers” and may serve as testing ground for other gravity theories. In this context we explore how complexity of compact objects (a fundamentally theoretical classification) is connected to the photon ring (an astrophysical observable in the universe) and its stability. We consider zero complexity systems and discuss its significance with respect to (wrt) formation of photon rings and hence shadows.
{"title":"Herrera complexity and shadows of spherically symmetric compact objects","authors":"Subhasis Nalui, Subhra Bhattacharya","doi":"10.1016/j.physletb.2025.139261","DOIUrl":"10.1016/j.physletb.2025.139261","url":null,"abstract":"<div><div>In this work we investigate the effect of complexity factor on the formation of photon spheres for spherically symmetric compact objects. The complexity factor obtained from the orthogonal splitting of the Riemann curvature tensor connects the geometric attributes of a compact spherically symmetric gravitating object with its matter inhomogeneity and pressure anisotropy via a scalar term. The novelty of the complexity factor is the inherent simple definition that identifies the evolution of matter tensors inside a given region of space-time. Such identification helps to obtain an equivalence class of gravitating compact objects based on their degree of complexity with zero complexity identified as the simplest system. On the other hand shadows and photon rings have become essential for identifying compact regions of space time characterised by massive gravity. Advanced observational data analysis tools augments the hope for identification of exotic gravitational objects, like the so called “black hole mimickers” and may serve as testing ground for other gravity theories. In this context we explore how complexity of compact objects (a fundamentally theoretical classification) is connected to the photon ring (an astrophysical observable in the universe) and its stability. We consider zero complexity systems and discuss its significance with respect to (wrt) formation of photon rings and hence shadows.</div></div>","PeriodicalId":20162,"journal":{"name":"Physics Letters B","volume":"861 ","pages":"Article 139261"},"PeriodicalIF":4.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143035238","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01DOI: 10.1016/j.physletb.2024.139229
Nadir Ijaz, Mansoor Ur Rehman
This study investigates the realization of R-symmetric Higgs inflation within the framework of no-scale-like supergravity, aiming to elucidate the formation of primordial black holes and observable gravitational waves within a class of GUT models. We explore the possibility of an ultra-slow-roll phase in a hybrid inflation framework, where the GUT Higgs field primarily takes on the role of the inflaton. The amplification of the scalar power spectrum gives rise to scalar-induced gravitational waves and the generation of primordial black holes. The predicted stochastic gravitational wave background falls within the sensitivity range of existing and upcoming gravitational wave detectors, while primordial black holes hold the potential to explain the abundance of dark matter. Furthermore, we highlight the significance of the leading-order nonrenormalizable term in the superpotential of achieving inflationary observables consistent with the latest experimental data. Additionally, the predicted range of the tensor-to-scalar ratio, a key measure of primordial gravitational waves, lies within the observational window of future experiments searching for B-mode polarization patterns in cosmic microwave background data.
{"title":"Exploring primordial black holes and gravitational waves with R-symmetric GUT Higgs inflation","authors":"Nadir Ijaz, Mansoor Ur Rehman","doi":"10.1016/j.physletb.2024.139229","DOIUrl":"10.1016/j.physletb.2024.139229","url":null,"abstract":"<div><div>This study investigates the realization of R-symmetric Higgs inflation within the framework of no-scale-like supergravity, aiming to elucidate the formation of primordial black holes and observable gravitational waves within a class of GUT models. We explore the possibility of an ultra-slow-roll phase in a hybrid inflation framework, where the GUT Higgs field primarily takes on the role of the inflaton. The amplification of the scalar power spectrum gives rise to scalar-induced gravitational waves and the generation of primordial black holes. The predicted stochastic gravitational wave background falls within the sensitivity range of existing and upcoming gravitational wave detectors, while primordial black holes hold the potential to explain the abundance of dark matter. Furthermore, we highlight the significance of the leading-order nonrenormalizable term in the superpotential of achieving inflationary observables consistent with the latest experimental data. Additionally, the predicted range of the tensor-to-scalar ratio, a key measure of primordial gravitational waves, lies within the observational window of future experiments searching for B-mode polarization patterns in cosmic microwave background data.</div></div>","PeriodicalId":20162,"journal":{"name":"Physics Letters B","volume":"861 ","pages":"Article 139229"},"PeriodicalIF":4.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142925273","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01DOI: 10.1016/j.physletb.2024.139234
S. Habib Mazharimousavi
Inspired by the geometry of the Ernst black hole which interpolates the static spherically symmetric Schwarzschild black hole and the static axially symmetric magnetic Melvin spacetime, in this paper, we aim to present a solution to Einstein's field equation in vacuum to interpolate the Schwarzschild black hole and the Levi-Civita spacetime. Hence, we shall call the solution the Schwarzschild-Levi-Civita black hole. Effectively the solution is a two-parameter non-asymptotically flat black hole that is static, axially symmetric, and singular in its axis of symmetry.
{"title":"Schwarzschild-Levi-Civita black hole","authors":"S. Habib Mazharimousavi","doi":"10.1016/j.physletb.2024.139234","DOIUrl":"10.1016/j.physletb.2024.139234","url":null,"abstract":"<div><div>Inspired by the geometry of the Ernst black hole which interpolates the static spherically symmetric Schwarzschild black hole and the static axially symmetric magnetic Melvin spacetime, in this paper, we aim to present a solution to Einstein's field equation in vacuum to interpolate the Schwarzschild black hole and the Levi-Civita spacetime. Hence, we shall call the solution the Schwarzschild-Levi-Civita black hole. Effectively the solution is a two-parameter non-asymptotically flat black hole that is static, axially symmetric, and singular in its axis of symmetry.</div></div>","PeriodicalId":20162,"journal":{"name":"Physics Letters B","volume":"861 ","pages":"Article 139234"},"PeriodicalIF":4.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142925282","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01DOI: 10.1016/j.physletb.2024.139235
Si-Wei Han , Zhichun Ouyang , Zhiyao Hu , Jun Feng
We revisit the problem of the thermalization process in an entropic formulation for the Unruh-DeWitt (UDW) detector outside a Schwarzschild black hole. We derive the late-time dynamics of the detector in the context of open quantum system, and capture the path distinguishability and thermodynamic irreversibility of detector thermalization process by using quantum relative entropy (QRE). We find that beyond the Planckian transition rate, the refined thermalization process in detector Hilbert space can be distinguished by the time behavior of the related QRE. We show that the exotic position-dependent behaviors of the QRE emerge corresponding to different choices of black hole vacua (i.e., the Boulware, Hartle-Hawking, and Unruh vacua). Finally, from a perspective of quantum thermodynamics, we recast the free energy change of the UDW detector undergoing Hawking radiation into an entropic combination form, where the classical Kullback-Leibler divergence and quantum coherence are presented in specific QRE-like forms. With growing Hawking temperature, we find that the consumption rate of quantum coherence is larger than that of its classical counterpart.
{"title":"Relative entropy formulation of thermalization process in a Schwarzschild spacetime","authors":"Si-Wei Han , Zhichun Ouyang , Zhiyao Hu , Jun Feng","doi":"10.1016/j.physletb.2024.139235","DOIUrl":"10.1016/j.physletb.2024.139235","url":null,"abstract":"<div><div>We revisit the problem of the thermalization process in an entropic formulation for the Unruh-DeWitt (UDW) detector outside a Schwarzschild black hole. We derive the late-time dynamics of the detector in the context of open quantum system, and capture the path distinguishability and thermodynamic irreversibility of detector thermalization process by using quantum relative entropy (QRE). We find that beyond the Planckian transition rate, the refined thermalization process in detector Hilbert space can be distinguished by the time behavior of the related QRE. We show that the exotic position-dependent behaviors of the QRE emerge corresponding to different choices of black hole vacua (i.e., the Boulware, Hartle-Hawking, and Unruh vacua). Finally, from a perspective of quantum thermodynamics, we recast the free energy change of the UDW detector undergoing Hawking radiation into an entropic combination form, where the classical Kullback-Leibler divergence and quantum coherence are presented in specific QRE-like forms. With growing Hawking temperature, we find that the consumption rate of quantum coherence is larger than that of its classical counterpart.</div></div>","PeriodicalId":20162,"journal":{"name":"Physics Letters B","volume":"861 ","pages":"Article 139235"},"PeriodicalIF":4.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142967777","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01DOI: 10.1016/j.physletb.2025.139262
Boris Tomášik , Marcus Bleicher
We calculate the contribution of the decay products of excited nuclear cluster states to the event-by-event fluctuations of protons in the energy range from GeV within the statistical model. We find that the inclusion of the excited nuclear clusters yields corrections to all cumulant ratios, ranging from 1% for ratio of second to first-order cumulant to 100% for the sixth to second order cumulant towards the lowest inspected energy. As expected the contribution of excited cluster states is most important at low energies GeV and becomes negligible at higher collision energies. Especially in light of the expected ultra-high precision data from CBM at FAIR, this new contribution is important to allow for a quantitative comparison with (potentially later available) lattice QCD or effective model results.
{"title":"Excited cluster states: A new source for proton number fluctuations in the high baryon density regime","authors":"Boris Tomášik , Marcus Bleicher","doi":"10.1016/j.physletb.2025.139262","DOIUrl":"10.1016/j.physletb.2025.139262","url":null,"abstract":"<div><div>We calculate the contribution of the decay products of excited nuclear cluster states to the event-by-event fluctuations of protons in the energy range from <span><math><msqrt><mrow><msub><mrow><mi>s</mi></mrow><mrow><mi>N</mi><mi>N</mi></mrow></msub></mrow></msqrt><mo>=</mo><mn>2</mn><mo>−</mo><mn>5</mn></math></span> GeV within the statistical model. We find that the inclusion of the excited nuclear clusters yields corrections to all cumulant ratios, ranging from 1% for ratio of second to first-order cumulant to 100% for the sixth to second order cumulant towards the lowest inspected energy. As expected the contribution of excited cluster states is most important at low energies <span><math><msqrt><mrow><msub><mrow><mi>s</mi></mrow><mrow><mi>N</mi><mi>N</mi></mrow></msub></mrow></msqrt><mo><</mo><mn>3.5</mn></math></span> GeV and becomes negligible at higher collision energies. Especially in light of the expected ultra-high precision data from CBM at FAIR, this new contribution is important to allow for a quantitative comparison with (potentially later available) lattice QCD or effective model results.</div></div>","PeriodicalId":20162,"journal":{"name":"Physics Letters B","volume":"861 ","pages":"Article 139262"},"PeriodicalIF":4.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142989371","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01DOI: 10.1016/j.physletb.2025.139257
B. Huang , F.P. Bai , J.G. Li , D.Q. Fang , S.M. Wang
Two-proton (2p) radioactivity represents a rare decay mode that has been experimentally observed only in a selected few nuclei. The exploration of 2p emission is crucial for elucidating the structure, mass, and nucleon-nucleon interactions within exotic proton-rich nuclei. 39Ti has long been postulated as a potential candidate for 2p emission; however, experimental investigations have yet to confirm its 2p decay. To provide more accurate information for further studies, we utilize the Gamow shell model (GSM) and the Gamow coupled channel (GCC) method to analyze the prospective 2p radioactivity of isotopes 38,39Ti. Our calculations suggest that 39Ti is indeed a viable candidate for 2p emission. Notably, the estimated partial 2p decay width for 39Ti, predicted from the three-body GCC method, suggests that its 2p decay could rival its β decay in likelihood, although this is highly dependent on the specific 2p decay energy. Additionally, our analysis indicates a propensity for pairing between the valence protons in 39Ti. A similar investigative approach reveals that 38Ti exhibits a higher 2p decay energy and a broader decay width than 39Ti, positioning it as a more promising candidate for 2p decay.
{"title":"Exploring the possible two-proton radioactivity of 38,39Ti","authors":"B. Huang , F.P. Bai , J.G. Li , D.Q. Fang , S.M. Wang","doi":"10.1016/j.physletb.2025.139257","DOIUrl":"10.1016/j.physletb.2025.139257","url":null,"abstract":"<div><div>Two-proton (2<em>p</em>) radioactivity represents a rare decay mode that has been experimentally observed only in a selected few nuclei. The exploration of 2<em>p</em> emission is crucial for elucidating the structure, mass, and nucleon-nucleon interactions within exotic proton-rich nuclei. <sup>39</sup>Ti has long been postulated as a potential candidate for 2<em>p</em> emission; however, experimental investigations have yet to confirm its 2<em>p</em> decay. To provide more accurate information for further studies, we utilize the Gamow shell model (GSM) and the Gamow coupled channel (GCC) method to analyze the prospective 2<em>p</em> radioactivity of isotopes <sup>38,39</sup>Ti. Our calculations suggest that <sup>39</sup>Ti is indeed a viable candidate for 2<em>p</em> emission. Notably, the estimated partial 2<em>p</em> decay width for <sup>39</sup>Ti, predicted from the three-body GCC method, suggests that its 2<em>p</em> decay could rival its <em>β</em> decay in likelihood, although this is highly dependent on the specific 2<em>p</em> decay energy. Additionally, our analysis indicates a propensity for pairing between the valence protons in <sup>39</sup>Ti. A similar investigative approach reveals that <sup>38</sup>Ti exhibits a higher 2<em>p</em> decay energy and a broader decay width than <sup>39</sup>Ti, positioning it as a more promising candidate for 2<em>p</em> decay.</div></div>","PeriodicalId":20162,"journal":{"name":"Physics Letters B","volume":"861 ","pages":"Article 139257"},"PeriodicalIF":4.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142989372","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01DOI: 10.1016/j.physletb.2025.139272
Iver H. Brevik , Moshe M. Chaichian , Anca Tureanu
A magnetic field above the Schwinger critical value Tesla is much higher than any magnetic field known by now in the interstellar bulk except in the vicinity of observed magnetars having magnetic fields between 109 and 1011 Tesla. Above the critical magnetic field limit, calculated by Schwinger in the lowest order perturbation in quantum electrodynamics (QED), one reaches the threshold for electron-positron pair creation (through the intermediate electric field, as known also from standard electrodynamics), which has interesting consequences. Therefore, finding out whether one could encounter some consequences of interest also for the values of the magnetic field below the Schwinger critical point, we invoke the next higher-order effect in QED, which is emerging from the Quantum Vacuum Effect. The latter is equivalent to the use of the Euler-Heisenberg effective theory in nonlinear electrodynamics, where the Lagrangian has now a term with a higher power, . In this case, in the region , we show that interesting effects appear, among them the Cherenkov radiation and the reduction in the speed of light. The latter effects appear due to the quantum vacuum mimicking a medium. We also present quantitative arguments for such a close analogy. As a rough estimate, we show that the time delay τ of gamma-ray bursts (GRB) having traveled through the entire cosmological distances in an average strong magnetic field such as 106 Tesla, reaches an experimentally considerable value of hours. Of course in the vicinity of magnetars, the magnetic field is much stronger, of the order of Tesla. However, in this case the linear scale of GRB trajectory through such regions would be much smaller. For the latter, we also give a corresponding estimate for the number of the magnetars along the trajectory and also for the delay. Finally, we shall dwell on the recently raised issue in the literature, namely the Lorentz invariance violation (LIV).
{"title":"Below the Schwinger critical magnetic field value, quantum vacuum and gamma-ray bursts delay","authors":"Iver H. Brevik , Moshe M. Chaichian , Anca Tureanu","doi":"10.1016/j.physletb.2025.139272","DOIUrl":"10.1016/j.physletb.2025.139272","url":null,"abstract":"<div><div>A magnetic field above the Schwinger critical value <span><math><msub><mrow><mi>B</mi></mrow><mrow><mi>crit</mi></mrow></msub><mo>=</mo><msup><mrow><mn>10</mn></mrow><mrow><mn>9</mn></mrow></msup></math></span> Tesla is much higher than any magnetic field known by now in the interstellar bulk except in the vicinity of observed magnetars having magnetic fields between 10<sup>9</sup> and 10<sup>11</sup> Tesla. Above the critical magnetic field limit, calculated by Schwinger in the lowest order perturbation in quantum electrodynamics (QED), one reaches the threshold for electron-positron pair creation (through the intermediate electric field, as known also from standard electrodynamics), which has interesting consequences. Therefore, finding out whether one could encounter some consequences of interest also for the values of the magnetic field below the Schwinger critical point, we invoke the next higher-order effect in QED, which is emerging from the <em>Quantum Vacuum Effect</em>. The latter is equivalent to the use of the Euler-Heisenberg effective theory in nonlinear electrodynamics, where the Lagrangian has now a term with a higher power, <span><math><msup><mrow><mi>B</mi></mrow><mrow><mn>4</mn></mrow></msup></math></span>. In this case, in the region <span><math><mi>B</mi><mo><</mo><msub><mrow><mi>B</mi></mrow><mrow><mi>crit</mi></mrow></msub></math></span>, we show that interesting effects appear, among them the Cherenkov radiation and the reduction in the speed of light. The latter effects appear due to the quantum vacuum mimicking a medium. We also present quantitative arguments for such a close analogy. As a rough estimate, we show that the time delay <em>τ</em> of gamma-ray bursts (GRB) having traveled through the entire cosmological distances in an average strong magnetic field such as 10<sup>6</sup> Tesla, reaches an experimentally considerable value of <span><math><mi>τ</mi><mo>=</mo><mn>2.4</mn></math></span> hours. Of course in the vicinity of magnetars, the magnetic field is much stronger, of the order of <span><math><msup><mrow><mn>10</mn></mrow><mrow><mn>9</mn></mrow></msup><mo>−</mo><msup><mrow><mn>10</mn></mrow><mrow><mn>11</mn></mrow></msup></math></span> Tesla. However, in this case the linear scale of GRB trajectory through such regions would be much smaller. For the latter, we also give a corresponding estimate for the number of the magnetars along the trajectory and also for the delay. Finally, we shall dwell on the recently raised issue in the literature, namely the Lorentz invariance violation (LIV).</div></div>","PeriodicalId":20162,"journal":{"name":"Physics Letters B","volume":"861 ","pages":"Article 139272"},"PeriodicalIF":4.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143035212","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01DOI: 10.1016/j.physletb.2025.139249
Hemant Rathi , Dibakar Roychowdhury
We present a JT gravity setup coupled with and Yang-Mills fields in two dimensions that reveals the onset of a small black hole to large black hole phase transition at finite chemical potential(s). We identify these black hole solutions as “topological defects” in the thermodynamic phase space and calculate the associated topological numbers following the standard procedure. We confirm the robustness of our model by estimating perturbative corrections to the bulk free energy at an arbitrary order in the Yang-Mills coupling. We also construct the Schwarzian for the boundary theory using the 2D gravitational action in the bulk and comment on the dual SYK like model where similar observations can be made.
{"title":"Topology of black hole phase transition in JT gravity","authors":"Hemant Rathi , Dibakar Roychowdhury","doi":"10.1016/j.physletb.2025.139249","DOIUrl":"10.1016/j.physletb.2025.139249","url":null,"abstract":"<div><div>We present a JT gravity setup coupled with <span><math><mi>U</mi><mo>(</mo><mn>1</mn><mo>)</mo></math></span> and <span><math><mi>S</mi><mi>U</mi><mo>(</mo><mn>2</mn><mo>)</mo></math></span> Yang-Mills fields in two dimensions that reveals the onset of a small black hole to large black hole phase transition at finite chemical potential(s). We identify these black hole solutions as “topological defects” in the thermodynamic phase space and calculate the associated topological numbers following the standard procedure. We confirm the robustness of our model by estimating perturbative corrections to the bulk free energy at an arbitrary order in the Yang-Mills coupling. We also construct the Schwarzian for the boundary theory using the 2D gravitational action in the bulk and comment on the dual SYK like model where similar observations can be made.</div></div>","PeriodicalId":20162,"journal":{"name":"Physics Letters B","volume":"861 ","pages":"Article 139249"},"PeriodicalIF":4.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143035244","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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