Fortschritte Der Physik-Progress of Physics最新文献

{"title":"Thermodynamic Constraints and Future Singularities in Unimodular Gravity Driven by Phantom and Non-Phantom Fluids","authors":"Norman Cruz, Samuel Lepe, Guillermo Palma, Miguel Cruz","doi":"10.1002/prop.70158","DOIUrl":"https://doi.org/10.1002/prop.70158","url":null,"abstract":"<div>\u0000 \u0000 <p>This work investigates future cosmological singularities in a flat FLRW universe filled with a single barotropic fluid, (<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>p</mi>\u0000 <mo>=</mo>\u0000 <mo>(</mo>\u0000 <mi>γ</mi>\u0000 <mo>−</mo>\u0000 <mn>1</mn>\u0000 <mo>)</mo>\u0000 <mi>ρ</mi>\u0000 </mrow>\u0000 <annotation>$p = (gamma - 1)rho$</annotation>\u0000 </semantics></math>), within the framework of unimodular gravity. In this setting, the non-conservation of the energy–momentum tensor is encoded through an energy diffusion function <span></span><math>\u0000 <semantics>\u0000 <mi>Q</mi>\u0000 <annotation>$Q$</annotation>\u0000 </semantics></math>. While a constant diffusion term leads to an effective cosmological constant and preserves adiabatic evolution, a time-dependent <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>Q</mi>\u0000 <mo>(</mo>\u0000 <mi>t</mi>\u0000 <mo>)</mo>\u0000 </mrow>\u0000 <annotation>$Q(t)$</annotation>\u0000 </semantics></math> induces non-adiabatic dynamics. We consider a power-law Ansatz for <span></span><math>\u0000 <semantics>\u0000 <mi>Q</mi>\u0000 <annotation>$Q$</annotation>\u0000 </semantics></math> as a function of the redshift and impose the condition of positive entropy production. In particular, within the thermodynamically allowed sector, we show that Big Rip singularities are excluded for non-phantom fluids when the cosmological constant is positive. For phantom fluids, the model reproduces the expected Big Rip behavior, whereas non-phantom fluids with a negative cosmological constant end in a Big Crunch. Diffusion can induce an effective phantom behavior of the fluid itself, but it is always compensated by the decrease of the effective vacuum energy <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>Λ</mi>\u0000 <mo>+</mo>\u0000 <mi>Q</mi>\u0000 </mrow>\u0000 <annotation>$Lambda +Q$</annotation>\u0000 </semantics></math>, so the total effective equation of state never crosses the phantom divide. Moreover, positive entropy production forces the diffusion term to decrease in time. When it decreases without bound (<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>β</mi>\u0000 <mo><</mo>\u0000 <mn>0</mn>\u0000 </mrow>\u0000 <annotation>$beta <0$</annotation>\u0000 </semantics></math>), the effective vacuum energy becomes negative and the universe recollapses into a Big Crunch even for <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>Λ</mi>\u0000 <","PeriodicalId":55150,"journal":{"name":"Fortschritte Der Physik-Progress of Physics","volume":"74 10","pages":""},"PeriodicalIF":5.4,"publicationDate":"2026-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149205859","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":"Foundations of Wilson Lines and Loops From Basic Concepts to Gauge Field Reconstruction","authors":"Shokoufe Faraji","doi":"10.1002/prop.70156","DOIUrl":"https://doi.org/10.1002/prop.70156","url":null,"abstract":"<p>This review presents a concise and unified treatment of Wilson lines and Wilson loops in continuum gauge theory, emphasizing their interpretation as parallel transport and their status as gauge covariant transporters and gauge invariant loop observables. Starting from the problem of comparing charged fields at separated points, we derive the path ordered exponential formulation and collect the key kinematical identities: gauge covariance, composition under path concatenation, inversion, and base point dependence. We then explain how local information is encoded in suitable small segment and small loop limits, and how these limits enter reconstruction questions for the underlying gauge connection. Seen as an inverse problem, this perspective clarifies how much of the gauge connection is encoded in loop observables and why traced Wilson loops, while gauge invariant, are intrinsically lossy without additional input. Special attention is given to clarifying common sources of confusion, in particular the distinction between untraced holonomies and traced Wilson loops, and the role of reference path choices when relating open transports to based loop data. The presentation is intended to serve both as an entry point for newcomers and as a compact reference for readers in high energy theory, mathematical physics, and related fields.</p>","PeriodicalId":55150,"journal":{"name":"Fortschritte Der Physik-Progress of Physics","volume":"74 10","pages":""},"PeriodicalIF":5.4,"publicationDate":"2026-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/prop.70156","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149146556","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":"Issue Information: Fortschritte der Physik 10 / 2026","authors":"","doi":"10.1002/prop.70155","DOIUrl":"https://doi.org/10.1002/prop.70155","url":null,"abstract":"","PeriodicalId":55150,"journal":{"name":"Fortschritte Der Physik-Progress of Physics","volume":"74 10","pages":""},"PeriodicalIF":5.4,"publicationDate":"2026-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/prop.70155","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149084100","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":"Revisiting the S8 Gap: Non-Metricity in Light of DESI DR2 and Gravitational Wave Standard Sirens","authors":"Devaraja Mallesha Naik","doi":"10.1002/prop.70152","DOIUrl":"https://doi.org/10.1002/prop.70152","url":null,"abstract":"&lt;div&gt;\u0000 \u0000 &lt;p&gt;The &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;Λ&lt;/mi&gt;\u0000 &lt;mi&gt;CDM&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt;$Lambda{rm CDM}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; model faces persistent discrepancies between early- and late-Universe measurements of the Hubble constant (&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;H&lt;/mi&gt;\u0000 &lt;mn&gt;0&lt;/mn&gt;\u0000 &lt;/msub&gt;\u0000 &lt;annotation&gt;$H_0$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;) and matter clustering (&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;S&lt;/mi&gt;\u0000 &lt;mn&gt;8&lt;/mn&gt;\u0000 &lt;/msub&gt;\u0000 &lt;annotation&gt;$S_8$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;). We investigate whether the metric-affine framework of &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;f&lt;/mi&gt;\u0000 &lt;mo&gt;(&lt;/mo&gt;\u0000 &lt;mi&gt;Q&lt;/mi&gt;\u0000 &lt;mo&gt;)&lt;/mo&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt;$f(Q)$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; symmetric teleparallel gravity can accommodate these tensions. Constraining the reciprocal &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;f&lt;/mi&gt;\u0000 &lt;mo&gt;(&lt;/mo&gt;\u0000 &lt;mi&gt;Q&lt;/mi&gt;\u0000 &lt;mo&gt;)&lt;/mo&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt;$f(Q)$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; model with DESI DR2 BAO, Pantheon+ Supernovae, and RSD data, our joint MCMC analysis reveals a mild preference for a negative geometric density parameter (&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;Ω&lt;/mi&gt;\u0000 &lt;mi&gt;Q&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;mo&gt;=&lt;/mo&gt;\u0000 &lt;mo&gt;−&lt;/mo&gt;\u0000 &lt;mn&gt;0.164&lt;/mn&gt;\u0000 &lt;mo&gt;±&lt;/mo&gt;\u0000 &lt;mn&gt;0.070&lt;/mn&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt;$Omega _Q = -0.164 pm 0.070$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;). Within the reciprocal &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;f&lt;/mi&gt;\u0000 &lt;mo&gt;(&lt;/mo&gt;\u0000 &lt;mi&gt;Q&lt;/mi&gt;\u0000 &lt;mo&gt;)&lt;/mo&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt;$f(Q)$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; framework, such values modify the late-time growth history through a reduction of the effective gravitational coupling, yielding an intermediate clustering amplitude (&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;S&lt;/mi&gt;\u0000 &lt;mn&gt;8&lt;/mn&gt;\u0000 &lt;/msub&gt;\u0000 &lt;mo&gt;=&lt;/mo&gt;\u0000 &lt;mn&gt;0.815&lt;/mn&gt;\u0000 &lt;mo&gt;±&lt;/mo&gt;\u0000 &lt;mn&gt;0.029&lt;/mn&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;an","PeriodicalId":55150,"journal":{"name":"Fortschritte Der Physik-Progress of Physics","volume":"74 10","pages":""},"PeriodicalIF":5.4,"publicationDate":"2026-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149084101","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":"Stable Three-Dimensional Lattice Solitons in Spin-Orbit-Coupled Bose-Einstein Condensates","authors":"Liangwei Zeng,&nbsp;Boris A. Malomed,&nbsp;Yaroslav V. Kartashov,&nbsp;Xing Zhu","doi":"10.1002/prop.70153","DOIUrl":"https://doi.org/10.1002/prop.70153","url":null,"abstract":"<div>\u0000 \u0000 <p>We address three-dimensional (3D) solitons maintained by spin-orbit coupling (SOC) in the binary self-interacting Bose-Einstein condensate (BEC) held in the 3D optical lattice (OL). The analysis reveals that the SOC-OL interplay results in the formation of stable full-vortex (FV) solitons, built as sets of four density peaks residing in neighboring wells of the lattice potential, with the superimposed global vortical phase, and site-centered semi-vortices (SVs), in which the vorticity is present in only one component. The FV solitons, with their specific phase textures, do not exist in a uniform BEC with SOC. FV and SV states in the binary self-attractive BEC are stable despite the possibility of the supercritical collapse in the 3D system. Such states also exist, as gap solitons, in the self-repulsive 3D system. In terms of the chemical potential and number of particles, the stability regions of the 3D FV solitons and SVs expand with the increase of the SOC strength and OL depth. The results open the route to the creation of 3D complexes of vorticity-carrying condensates that can be realized with existing experimental techniques.</p>\u0000 </div>","PeriodicalId":55150,"journal":{"name":"Fortschritte Der Physik-Progress of Physics","volume":"74 9","pages":""},"PeriodicalIF":5.4,"publicationDate":"2026-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149146954","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 Black Holes From a Novel Nonlinear Electrodynamics Model Based on Electric Potential Regularization","authors":"S. Habib Mazharimousavi,&nbsp;H. Karyal","doi":"10.1002/prop.70154","DOIUrl":"https://doi.org/10.1002/prop.70154","url":null,"abstract":"<div>\u0000 \u0000 <p>We propose a nonlinear electrodynamics (NED) model constructed by regularizing the electric scalar potential of a point charge rather than its electric field. The motivation for this potential-based construction is that an elementary closed-form electrostatic potential can be employed directly in atomic and other quantum-mechanical bound-state problems, whereas in several established NED models the point-charge potential is non-elementary and such applications generally require approximations or numerical treatments. Additionally, the resulting electrostatic configuration is nonsingular, has finite self-energy, and recovers Maxwell electrodynamics asymptotically. We derive the corresponding parametric NED model and energy–momentum tensor and show that the weak, null, and dominant energy conditions are satisfied, while the strong energy condition is violated. By minimally coupling the model to Einstein gravity, we obtain an exact static and spherically symmetric charged black-hole solution with a rich horizon structure, including simple, double, and triple horizons as well as naked singularities, depending on the mass and charge parameters. The geometry approaches Reissner–Nordström asymptotically but exhibits significant strong-field deviations. We further analyze null and timelike geodesics of the background metric and identify parameter regimes admitting exterior stable metric-null circular orbits and static equilibrium configurations (Dyson-like shells). Thus, the construction provides an analytically tractable potential-based NED framework that connects charged black-hole solutions with possible future applications to quantum bound-state systems.</p>\u0000 </div>","PeriodicalId":55150,"journal":{"name":"Fortschritte Der Physik-Progress of Physics","volume":"74 9","pages":""},"PeriodicalIF":5.4,"publicationDate":"2026-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149048503","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":"Kaniadakis Holographic Dark Energy: UV–IR Duality, Horizon Thermodynamics, and Cosmological Constraints","authors":"Manuel Gonzalez-Espinoza,&nbsp;Samuel Lepe,&nbsp;Joel F. Saavedra,&nbsp;Francisco Tello-Ortiz","doi":"10.1002/prop.70151","DOIUrl":"https://doi.org/10.1002/prop.70151","url":null,"abstract":"&lt;div&gt;\u0000 \u0000 &lt;p&gt;We investigate the cosmological and thermodynamic implications of holographic dark energy derived from the Kaniadakis deformation of the Bekenstein–Hawking entropy. In a spatially flat FLRW universe, the generalized entropy generates an effective dark-energy density with an infrared correction proportional to &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;msup&gt;\u0000 &lt;mi&gt;H&lt;/mi&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mo&gt;−&lt;/mo&gt;\u0000 &lt;mn&gt;2&lt;/mn&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/msup&gt;\u0000 &lt;annotation&gt;$H^{-2}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;, naturally producing an ultraviolet–infrared structure in the cosmological dynamics. Using the Hayward–Kodama formulation of apparent-horizon thermodynamics, we derive a geometric equation of state and identify Van der Waals-type criticality, characterized by an inverted first-order phase transition and an inverted swallowtail Gibbs potential. We interpret this behavior as the thermodynamic signature of a geometric phase transition of the apparent horizon rather than standard fluid coexistence. We also consider an extended model with a &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mover&gt;\u0000 &lt;mi&gt;H&lt;/mi&gt;\u0000 &lt;mo&gt;̇&lt;/mo&gt;\u0000 &lt;/mover&gt;\u0000 &lt;annotation&gt;$dot{H}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; contribution inspired by the Granda–Oliveros cutoff and show that this unconventional critical behavior persists. At the perturbative level, the same ultraviolet–infrared competition controls the effective sound speed and dark-energy response through a dimensionless coupling &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;A&lt;/mi&gt;\u0000 &lt;mo&gt;(&lt;/mo&gt;\u0000 &lt;mi&gt;z&lt;/mi&gt;\u0000 &lt;mo&gt;)&lt;/mo&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt;$A(z)$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;, which acts as a geometric order parameter. In the minimal model, &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;A&lt;/mi&gt;\u0000 &lt;mo&gt;(&lt;/mo&gt;\u0000 &lt;mi&gt;z&lt;/mi&gt;\u0000 &lt;mo&gt;)&lt;/mo&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt;$A(z)$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; may cross zero during matter domination, marking a transition between infrared- and ultraviolet-dominated regimes, whereas the extended scenario remains ultraviolet dominated. Finally, we confront both models with cosmic chronometers, PantheonPlus Type Ia supernovae, DESI DR2 baryon acoustic oscillations, and redshift-space distortion data. Bayesian comparison with &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;Λ&lt;/mi&gt;\u0000 &lt;mi&gt;CDM&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt;$Lambda{rm CDM}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;, CPL, and standard holographic dark energy strongly disfavo","PeriodicalId":55150,"journal":{"name":"Fortschritte Der Physik-Progress of Physics","volume":"74 9","pages":""},"PeriodicalIF":5.4,"publicationDate":"2026-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149048198","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":"Modular Theory and Affine Representations on the Rindler Horizon","authors":"Michele Arzano,&nbsp;Paolo Palumbo","doi":"10.1002/prop.70150","DOIUrl":"https://doi.org/10.1002/prop.70150","url":null,"abstract":"<div>\u0000 \u0000 <p>We develop a group-theoretic interpretation of the Unruh effect based on affine symmetry on a light ray and relate it to modular theory. For a massless scalar field in two spacetime dimensions, inertial and uniformly accelerated observers select two different flows within the same chiral one-particle structure, respectively, null translations and dilations. Minkowski modes are adapted to translations, while Rindler modes are adapted to dilations, with the Mellin transform providing the natural bridge between them. When a Minkowski positive-frequency mode is restricted to a single Rindler wedge, its comparison with Rindler modes is non-unitary within the positive-frequency sector. Modular theory gives the corresponding operator-algebraic interpretation: on the horizon the modular flow of the half-line algebra is implemented by dilations, and the restricted vacuum satisfies the KMS condition. The affine group thus appears as the minimal symmetry structure underlying thermality on the Rindler horizon.</p></div>","PeriodicalId":55150,"journal":{"name":"Fortschritte Der Physik-Progress of Physics","volume":"74 9","pages":""},"PeriodicalIF":5.4,"publicationDate":"2026-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148994147","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":"Mach's Principle: The Alternative to Dark Energy for Cosmological Inflation","authors":"Shubhen BISWAS","doi":"10.1002/prop.70147","DOIUrl":"https://doi.org/10.1002/prop.70147","url":null,"abstract":"<div>\u0000 \u0000 <p>For the last few decades, the standard Lambda cold dark matter (∧-CDM) model and its variants have been in vogue to describe cosmological inflation following the Friedmann equation. In the apparently flat universe, any distance between two points can be considered as the radial extent of a Newton–Birkhoff's blob that is under co-expansion. Following Mach's principle, the potential of the universe must undergo repulsive interaction with a blob that relies on post-Newtonian gravity. This fact can easily mimic the influence of dark energy needed to sustain cosmological inflation. Taking the time-dependent modified Friedmann–Lemaitre–Robertson–Walker (FLRW) metric element, Einstein's field equation results in the Hubble parameter <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mspace></mspace>\u0000 <mn>72.2</mn>\u0000 <mspace></mspace>\u0000 <mi>k</mi>\u0000 <mi>m</mi>\u0000 <mo>.</mo>\u0000 <msup>\u0000 <mi>s</mi>\u0000 <mrow>\u0000 <mo>−</mo>\u0000 <mn>1</mn>\u0000 </mrow>\u0000 </msup>\u0000 <mo>.</mo>\u0000 <mi>M</mi>\u0000 <mi>p</mi>\u0000 <msup>\u0000 <mi>c</mi>\u0000 <mrow>\u0000 <mo>−</mo>\u0000 <mn>1</mn>\u0000 </mrow>\u0000 </msup>\u0000 </mrow>\u0000 <annotation>$ 72.2 km.{{s}^{ - 1}}.Mp{{c}^{ - 1}}$</annotation>\u0000 </semantics></math>, free from Hubble tension. It portrays a self-consistent and amicable alternative to the dark energy theory in exploring inflation solely on the baryonic density of the universe. This model predicts the age of our universe at 13.54 billion years with an expected total lifespan of 38.30 billion years at the Big Crunch.</p>\u0000 </div>","PeriodicalId":55150,"journal":{"name":"Fortschritte Der Physik-Progress of Physics","volume":"74 9","pages":""},"PeriodicalIF":5.4,"publicationDate":"2026-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148942872","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":"Observer Agreement and Entanglement Decay From Stochastic Relational Time Correlations","authors":"Pradosh Keshav MV","doi":"10.1002/prop.70148","DOIUrl":"https://doi.org/10.1002/prop.70148","url":null,"abstract":"<div>\u0000 \u0000 <p>We show that gravitational coarse-graining renders relational time a spatially correlated Gaussian stochastic field, with consequences for observer agreement and entanglement decay in spatially separated systems. Working in the ADM formulation of linearized gravity with a massless scalar field, we integrate out the transverse–traceless (TT) graviton sector within an effective field theory regulated at a coarse-graining scale. The Gaussian structure of the TT sector renders the path integral exact within the quadratic truncation, and the resulting influence functional admits an exact Hubbard–Stratonovich representation in terms of a Gaussian stochastic field. The accumulated relational time shift is a diffusive stochastic process whose variance grows linearly with observation time and carries an overall <span></span><math>\u0000 <semantics>\u0000 <msubsup>\u0000 <mi>M</mi>\u0000 <mi>Pl</mi>\u0000 <mrow>\u0000 <mo>−</mo>\u0000 <mn>4</mn>\u0000 </mrow>\u0000 </msubsup>\u0000 <annotation>$M_{rm Pl}^{-4}$</annotation>\u0000 </semantics></math> suppression. The normalized spatial correlation between clock fluctuations exhibits an <span></span><math>\u0000 <semantics>\u0000 <msup>\u0000 <mi>r</mi>\u0000 <mrow>\u0000 <mo>−</mo>\u0000 <mn>3</mn>\u0000 </mrow>\u0000 </msup>\u0000 <annotation>$r^{-3}$</annotation>\u0000 </semantics></math> decay and is independent of the overall gravitational coupling strength. These correlations enter two physical observables with opposite dependence: the visibility of observer agreement decays as a function of one minus the spatial correlation, while the concurrence of a spatially separated Bell pair decays as a function of one plus it. This asymmetry arises because observer agreement is governed by the difference of relational time shifts, whereas Bell-pair coherence is governed by their sum. Spatial correlations therefore improve observer agreement while accelerating entanglement decay.</p>\u0000 </div>","PeriodicalId":55150,"journal":{"name":"Fortschritte Der Physik-Progress of Physics","volume":"74 9","pages":""},"PeriodicalIF":5.4,"publicationDate":"2026-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148942762","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}