{"title":"Ringdown Modulation of Acceleration Radiation in the Schwarzschild Background","authors":"Reggie C. Pantig","doi":"10.1002/prop.70128","DOIUrl":"https://doi.org/10.1002/prop.70128","url":null,"abstract":"<p>We derive an analytic first-order description of how Schwarzschild ringdown affects a detector-based detailed-balance diagnostic in a near-horizon, single-mode setting. A freely falling two-level system couples to a cavity-filtered outgoing mode of fixed asymptotic frequency, whose static Schwarzschild response gives geometric photon statistics and a detailed-balance ratio governed by the surface gravity. We perturb this baseline by an even-parity, axisymmetric quadrupolar quasinormal mode and work in ingoing Eddington–Finkelstein coordinates, which are regular at the future horizon. The perturbation shifts the outgoing eikonal through the double-null contraction of the metric perturbation along the outgoing congruence. After fixing the residual endpoint phase calibration on the cavity worldtube, this redshift-map deformation induces a first-order decaying-oscillatory correction to the detector detailed-balance exponent at the quasinormal frequency. We express the geometric response through a closed boundary formula at the sampling radius and state the adiabatic, narrowband, and linear-response conditions under which the result applies. Detector details, including the gap, switching, and wavepacket profile, enter only through a smooth prefactor, while the ringdown dependence is carried by the quasinormal frequency and calibrated response coefficient. The modulation vanishes in the zero-amplitude, late-time, and stationary quadrupolar limits. The result is not a modification of the Hawking temperature, global Hawking flux, or dynamical horizon thermality, but a controlled correction to an operational detector/cavity detailed-balance observable.</p>","PeriodicalId":55150,"journal":{"name":"Fortschritte Der Physik-Progress of Physics","volume":"74 6","pages":""},"PeriodicalIF":5.4,"publicationDate":"2026-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/prop.70128","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148325008","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Abdulla Al Mamon, Andronikos Paliathanasis, Subhajit Saha
{"title":"Unifying the Dark Sector With the New Generalized Chaplygin Gas: Observational Constraints","authors":"Abdulla Al Mamon, Andronikos Paliathanasis, Subhajit Saha","doi":"10.1002/prop.70127","DOIUrl":"https://doi.org/10.1002/prop.70127","url":null,"abstract":"<div>\u0000 \u0000 <p>In light of recent cosmological observations, we examine a generalized Chaplygin gas model with a redshift-dependent exponent as a framework for describing the dark energy and dark matter content of the Universe. Specifically, we treat this fluid as a single unified component and test it against late-time background observational data. We employ Type Ia supernova data, cosmic chronometers, and baryon acoustic oscillations from the second data release of the Dark Energy Spectroscopic Instrument. We perform a Bayesian analysis for parameter estimation and compare the model with <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>Λ</mi>\u0000 <mi>CDM</mi>\u0000 </mrow>\u0000 <annotation>$Lambda{rm CDM}$</annotation>\u0000 </semantics></math>. We find that the generalized Chaplygin gas provides systematically higher values of the combined likelihood; nevertheless, once the larger number of free parameters is taken into account, both the Bayesian evidence and the Akaike Information Criterion suggest that the model is statistically indistinguishable from <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>Λ</mi>\u0000 <mi>CDM</mi>\u0000 </mrow>\u0000 <annotation>$Lambda{rm CDM}$</annotation>\u0000 </semantics></math>.</p></div>","PeriodicalId":55150,"journal":{"name":"Fortschritte Der Physik-Progress of Physics","volume":"74 6","pages":""},"PeriodicalIF":5.4,"publicationDate":"2026-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148324185","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":"Background Instability of Quintessence Model in Light of Entropy and Distance Conjecture","authors":"Min-Seok Seo","doi":"10.1002/prop.70125","DOIUrl":"https://doi.org/10.1002/prop.70125","url":null,"abstract":"<p>We apply the covariant entropy bound argument supporting the de Sitter swampland conjecture to the quintessence model, to find out the condition for the background to be unstable. More concretely, the background is unstable when the matter entropy given by the species number of the effective field theory increases more rapidly than the geometrical entropy proportional to the apparent horizon area, since it contradicts the covariant entropy bound. The rapid increase in the matter entropy is proposed by the distance conjecture, which states that the time evolution of some scalar field along the geodesic in the field space brings about the descent of a tower of states from UV. From this, we find that for the quintessence model, the unstable background admits the event horizon of finite size, and the converse is also true when the string tower is taken into account. Here, the presence of the event horizon implies that the trans-Planckian modes can be classicalized, violating the trans-Planckian censorship bound. We also point out that the scale separation between the Kaluza–Klein mass scale and the Hubble parameter can be realized when the product between the increasing rates of the matter and the geometrical entropies is bounded from below, which is consistent with the AdS distance conjecture. Our study suggests that various swampland conjectures can be comprehensively understood in the language of the entropy.</p>","PeriodicalId":55150,"journal":{"name":"Fortschritte Der Physik-Progress of Physics","volume":"74 6","pages":""},"PeriodicalIF":5.4,"publicationDate":"2026-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/prop.70125","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148281992","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Xuanke Zeng, Zhipeng Zhang, Han Kou, Milivoj R. Belić, Dumitru Mihalache, Jingzhen Li, Xing Zhu, Liangwei Zeng
{"title":"Ring-Shaped Gap Solitons and Vortices in Saturable Nonlinear Media","authors":"Xuanke Zeng, Zhipeng Zhang, Han Kou, Milivoj R. Belić, Dumitru Mihalache, Jingzhen Li, Xing Zhu, Liangwei Zeng","doi":"10.1002/prop.70123","DOIUrl":"https://doi.org/10.1002/prop.70123","url":null,"abstract":"<div>\u0000 \u0000 <p>We demonstrate that ring-shaped gap solitons can be stabilized in the nonlinear Schrödinger equation with saturable nonlinearity and a radially periodic linear lattice, encompassing both fundamental solitons and their vortex counterparts. Two types of solitons, distinguished by different numbers of ring peaks—specifically, single-ring and three-ring solitons, as well as their vortex analogues—are studied. By solving the governing equation, we establish the existence, properties, and stability of these localized solutions, complemented with direct propagation simulations. The power of all these soliton families decreases as the propagation constant increases, satisfying the anti-Vakhitov–Kolokolov criterion for soliton stability. Both stable and unstable examples of soliton propagation are displayed. Although they resemble truncated linear Bloch waves, the profiles of these annular solitons are intriguing, as minor peak rings become evident near the edges of the band gaps, causing instabilities. Notably, the phase profiles of ring-shaped vortex solitons differ from the conventional ones; that is, they exhibit spiraling patterns in the central region that alternate periodically in the radial direction.</p>\u0000 </div>","PeriodicalId":55150,"journal":{"name":"Fortschritte Der Physik-Progress of Physics","volume":"74 6","pages":""},"PeriodicalIF":7.8,"publicationDate":"2026-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148237950","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":"Charged Schwarzschild–Levi-Civita Black Hole via the Hassan–Sen Transformation in Heterotic String Theory","authors":"S. Habib Mazharimousavi","doi":"10.1002/prop.70121","DOIUrl":"https://doi.org/10.1002/prop.70121","url":null,"abstract":"<div>\u0000 \u0000 <p>We apply the Hassan–Sen transformation to the Schwarzschild–Levi-Civita vacuum solution and construct its charged generalization within the low-energy effective field theory of heterotic string theory. Starting from a static, axially symmetric seed metric, we obtain an exact Einstein–Maxwell-dilaton black hole in the Einstein frame and verify explicitly that it satisfies the full set of field equations. The resulting spacetime is characterized by a nontrivial dilaton field, an electric Maxwell field, and a strong angular anisotropy inherited from the Schwarzschild–Levi-Civita geometry. A detailed study of null geodesics reveals the impact of the electric field-dilaton-induced deformation on photon propagation, including the absence of circular photon orbits outside the horizon. In the special massless limit, we uncover the charged Levi-Civita spacetime with a line singularity aligned with the symmetry axis, exhibiting pronounced stretching and squashing behavior in different asymptotic regimes. These results demonstrate that the Hassan–Sen transformation provides a powerful mechanism for generating highly anisotropic charged solutions beyond the standard black hole sector of string-inspired gravity.</p>\u0000 </div>","PeriodicalId":55150,"journal":{"name":"Fortschritte Der Physik-Progress of Physics","volume":"74 6","pages":""},"PeriodicalIF":7.8,"publicationDate":"2026-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148173868","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":"Issue Information: Fortschritte der Physik 6 / 2026","authors":"","doi":"10.1002/prop.70122","DOIUrl":"https://doi.org/10.1002/prop.70122","url":null,"abstract":"","PeriodicalId":55150,"journal":{"name":"Fortschritte Der Physik-Progress of Physics","volume":"74 6","pages":""},"PeriodicalIF":7.8,"publicationDate":"2026-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/prop.70122","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148100397","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
{"title":"Einstein–Maxwell Equivalence in the \u0000 \u0000 λ\u0000 $lambda$\u0000 –\u0000 \u0000 R\u0000 $R$\u0000 Hořava–Lifshitz Model","authors":"Francisco Tello-Ortiz","doi":"10.1002/prop.70120","DOIUrl":"https://doi.org/10.1002/prop.70120","url":null,"abstract":"<div>\u0000 \u0000 <p>In this work, we analyze the <span></span><math>\u0000 <semantics>\u0000 <mi>λ</mi>\u0000 <annotation>$lambda$</annotation>\u0000 </semantics></math>–<span></span><math>\u0000 <semantics>\u0000 <mi>R</mi>\u0000 <annotation>$R$</annotation>\u0000 </semantics></math> model within the anisotropic electromagnetic–gravitational Hořava–Lifshitz theory. Starting from the Hamiltonian formulation of the electromagnetic–gravitational–dilaton system in <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mn>3</mn>\u0000 <mo>+</mo>\u0000 <mn>1</mn>\u0000 </mrow>\u0000 <annotation>$3+1$</annotation>\u0000 </semantics></math> dimensions obtained through a Kaluza–Klein reduction of the <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mn>4</mn>\u0000 <mo>+</mo>\u0000 <mn>1</mn>\u0000 </mrow>\u0000 <annotation>$4+1$</annotation>\u0000 </semantics></math> Hořava–Lifshitz theory, we consider the infrared regime with coupling constants <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>α</mi>\u0000 <mo>=</mo>\u0000 <mn>0</mn>\u0000 </mrow>\u0000 <annotation>$alpha =0$</annotation>\u0000 </semantics></math>, <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>β</mi>\u0000 <mo>=</mo>\u0000 <mn>1</mn>\u0000 </mrow>\u0000 <annotation>$beta =1$</annotation>\u0000 </semantics></math>, and the dilaton fixed at its ground state <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>ϕ</mi>\u0000 <mo>=</mo>\u0000 <mn>1</mn>\u0000 </mrow>\u0000 <annotation>$phi =1$</annotation>\u0000 </semantics></math>. We show that the Hamiltonian can be written as the Einstein–Maxwell Hamiltonian plus a term proportional to the square of the trace of the canonical momentum <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>P</mi>\u0000 <mo>=</mo>\u0000 <msub>\u0000 <mi>γ</mi>\u0000 <mrow>\u0000 <mi>i</mi>\u0000 <mi>j</mi>\u0000 </mrow>\u0000 </msub>\u0000 <msup>\u0000 <mi>p</mi>\u0000 <mrow>\u0000 <mi>i</mi>\u0000 <mi>j</mi>\u0000 </mrow>\u0000 </msup>\u0000 </mrow>\u0000 <annotation>$P=gamma _{ij}p^{ij}$</annotation>\u0000 </semantics></math>. The preservation in time of the Hamiltonian constraint leads to an elliptic equation whose only asymptotically flat solution is <span></span><math>\u0000 <semantics>\u0000 ","PeriodicalId":55150,"journal":{"name":"Fortschritte Der Physik-Progress of Physics","volume":"74 6","pages":""},"PeriodicalIF":7.8,"publicationDate":"2026-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148098477","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}