{"title":"Fuzzy Gravity: Four-Dimensional Gravity on a Covariant Noncommutative Space and Unification with Internal Interactions","authors":"Danai Roumelioti, Stelios Stefas, George Zoupanos","doi":"10.1002/prop.202400126","DOIUrl":"10.1002/prop.202400126","url":null,"abstract":"<p>In the present work, an extended description of the covariant noncommutative space is presented, which accommodates the Fuzzy Gravity model constructed previously. It is based on the historical lesson that the use of larger algebras containing all generators of the isometry of the continuous one helped in formulating a fuzzy covariant noncommutative space. Specifically a further enlargement of the isometry group leads the authors, in addition to the construction of the covariant noncommutative space, also to the suggestion of the group that should be gauged on such a space in order to construct a Fuzzy Gravity theory. As a result, two Fuzzy Gravity models are obtained, one in de Sitter and one in anti-de Sitter space, depending on the extension of the isometry group, and their spontaneous symmetry breaking leading to fuzzy versions of the noncommutative <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>S</mi>\u0000 <mi>O</mi>\u0000 <mo>(</mo>\u0000 <mn>1</mn>\u0000 <mo>,</mo>\u0000 <mn>3</mn>\u0000 <mo>)</mo>\u0000 </mrow>\u0000 <annotation>$SO(1,3)$</annotation>\u0000 </semantics></math> gravity are discussed. In addition, how to introduce fermions in the fuzzy gravity is discussed for the first time, and even more importantly, how to unify the constructed noncommutative-fuzzy gravity with internal interactions based on <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>S</mi>\u0000 <mi>O</mi>\u0000 <mo>(</mo>\u0000 <mn>10</mn>\u0000 <mo>)</mo>\u0000 </mrow>\u0000 <annotation>$SO(10)$</annotation>\u0000 </semantics></math> or <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>S</mi>\u0000 <mi>U</mi>\u0000 <mo>(</mo>\u0000 <mn>5</mn>\u0000 <mo>)</mo>\u0000 </mrow>\u0000 <annotation>$SU(5)$</annotation>\u0000 </semantics></math> as grand unified theories.</p>","PeriodicalId":55150,"journal":{"name":"Fortschritte Der Physik-Progress of Physics","volume":"72 9-10","pages":""},"PeriodicalIF":5.6,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/prop.202400126","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141881271","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":"Form Invariance of Raychaudhuri Equation in the Presence of Inflaton-Type Fields","authors":"Arijit Panda, Debashis Gangopadhyay, Goutam Manna","doi":"10.1002/prop.202400134","DOIUrl":"10.1002/prop.202400134","url":null,"abstract":"<p>We show that the Raychaudhuri equation (RE) remains form invariant for certain solutions of scalar fields <span></span><math>\u0000 <semantics>\u0000 <mi>ϕ</mi>\u0000 <annotation>$phi$</annotation>\u0000 </semantics></math> whose Lagrangian is non-canonical and of the form <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>L</mi>\u0000 <mo>(</mo>\u0000 <mi>X</mi>\u0000 <mo>,</mo>\u0000 <mi>ϕ</mi>\u0000 <mo>)</mo>\u0000 <mo>=</mo>\u0000 <mo>−</mo>\u0000 <mi>V</mi>\u0000 <mo>(</mo>\u0000 <mi>ϕ</mi>\u0000 <mo>)</mo>\u0000 <mi>F</mi>\u0000 <mo>(</mo>\u0000 <mi>X</mi>\u0000 <mo>)</mo>\u0000 </mrow>\u0000 <annotation>$mathcal {L}(X,phi)=-V(phi)F(X)$</annotation>\u0000 </semantics></math>, with <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>X</mi>\u0000 <mo>=</mo>\u0000 <mfrac>\u0000 <mn>1</mn>\u0000 <mn>2</mn>\u0000 </mfrac>\u0000 <msub>\u0000 <mi>g</mi>\u0000 <mrow>\u0000 <mi>μ</mi>\u0000 <mi>ν</mi>\u0000 </mrow>\u0000 </msub>\u0000 <msup>\u0000 <mo>∇</mo>\u0000 <mi>μ</mi>\u0000 </msup>\u0000 <mi>ϕ</mi>\u0000 <msup>\u0000 <mo>∇</mo>\u0000 <mi>ν</mi>\u0000 </msup>\u0000 <mi>ϕ</mi>\u0000 </mrow>\u0000 <annotation>$X=frac{1}{2} g_{mu nu } nabla ^{mu }phi nabla ^{nu } phi$</annotation>\u0000 </semantics></math> and <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>V</mi>\u0000 <mo>(</mo>\u0000 <mi>ϕ</mi>\u0000 <mo>)</mo>\u0000 </mrow>\u0000 <annotation>$V(phi)$</annotation>\u0000 </semantics></math> the potential. Solutions exist for both homogeneous and inhomogeneous fields that are like inflatons. Certain recent observations indicate that the cosmos is inhomogeneous and thus their results are in sync with latest observations. So the RE can accommodate primordial inhomogeneities as well as cosmologically relevant scenarios.</p>","PeriodicalId":55150,"journal":{"name":"Fortschritte Der Physik-Progress of Physics","volume":"72 9-10","pages":""},"PeriodicalIF":5.6,"publicationDate":"2024-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141865981","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":"Thermodynamic Properties of Regular Phantom Black Hole","authors":"Maryam Haditale, Behrooz Malekolkalami","doi":"10.1002/prop.202300267","DOIUrl":"10.1002/prop.202300267","url":null,"abstract":"<p>The Regular Phantom Black Hole (<b>RPBH</b>)s are of theoretical and observational importance, some of their properties have been studied. In this work, some of thermodynamical properties such as entropy, temperature, etc., in three background cases, that is, flat, de–Sitter (<b>dS</b>) and Anti–de Sitter (<b>AdS</b>) are studied. Many of the RPBH properties, including horizon radius, are (directly or indirectly) dependent on a scale parameter <span></span><math>\u0000 <semantics>\u0000 <mi>b</mi>\u0000 <annotation>$b$</annotation>\u0000 </semantics></math>. Due to the slightly different structure from Schwarzschild—like metrics, the method to express relations between thermodynamical variables requires a new function of the scale parameter. The local and global stability through the Heat Capacity (<b>HC</b>) and Gibbs free Energy (<b>GE</b>), respectively are also treated. In the AdS case, the regularized metric allows a Hawking-Page like phase transition of first order. The calculations and graphs show the results in the flat background, are very similar to Schwarzschild black hole and the asymptotically AdS RPBH is more compatible with physical laws than the dS and flat backgrounds.</p>","PeriodicalId":55150,"journal":{"name":"Fortschritte Der Physik-Progress of Physics","volume":"72 9-10","pages":""},"PeriodicalIF":5.6,"publicationDate":"2024-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141865983","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":"Rényi Holographic Dark Energy","authors":"Ratchaphat Nakarachinda, Chakrit Pongkitivanichkul, Daris Samart, Lunchakorn Tannukij, Pitayuth Wongjun","doi":"10.1002/prop.202400073","DOIUrl":"10.1002/prop.202400073","url":null,"abstract":"<p>In this work, the holographic dark energy model is constructed by using the non-extensive nature of the Schwarzschild black hole via the Rényi entropy. Due to the non-extensivity, the black hole can be stable under the process of fixing the non-extensive parameter. A change undergoing such a process would then motivate us to define the energy density of the Rényi holographic dark energy (RHDE). As a result, the RHDE with choosing the characteristic length scale as the Hubble radius provides the late-time expansion without the issue of causality. Remarkably, the proposed dark energy model contains the non-extensive length scale parameter additional to the standard <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> model. The cosmic evolution can be characterized by comparing the size of the Universe to this length scale. Moreover, the preferable value of the non-extensive length scale is determined by fitting the model to recent observations. The results of this work would shed light on the interplay between the thermodynamic description of the black hole with non-extensivity and the classical gravity description of the evolution of the Universe.</p>","PeriodicalId":55150,"journal":{"name":"Fortschritte Der Physik-Progress of Physics","volume":"72 7-8","pages":""},"PeriodicalIF":5.6,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141769726","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}
Chris Fields, James F. Glazebrook, Antonino Marcianò
{"title":"Communication Protocols and QECC From the Perspective of TQFT, Part II: QECCs as Spacetimes","authors":"Chris Fields, James F. Glazebrook, Antonino Marcianò","doi":"10.1002/prop.202400050","DOIUrl":"10.1002/prop.202400050","url":null,"abstract":"<p>Topological quantum field theories (TQFTs) provide a general, minimal-assumption language for describing quantum-state preparation and measurement. They therefore provide a general language in which to express multi-agent communication protocols, e.g., local operations, classical communication (LOCC) protocols. In the accompanying Part I, we construct LOCC protocols using TQFT, and show that LOCC protocols induce quantum error-correcting codes (QECCs) on the agent-environment boundary. Such QECCs can be regarded as implementing or inducing the emergence of spacetimes on such boundaries. Here connection between inter-agent communication and spacetime is investigated, by exploiting different realizations of TQFT. The authors delved into TQFTs that support on their boundaries spin-networks as computational systems: these are known as topological quantum neural networks (TQNNs). TQNNs, which have a natural representation as tensor networks, implement QECC. The HaPPY code is recognized to be a paradigmatic example. How generic QECCs, as bulk-boundary codes, induce effective spacetimes is then shown. The effective spatial and temporal separations that take place in QECC enables LOCC protocols between spatially separated observers. The implementation of QECCs in BF and Chern-Simons theories are then considered, and QECC-induced spacetimes are shown to provide the classical redundancy required for LOCC. Finally, the topological M-theory is considered as an implementation of QECC in higher spacetime dimensions.</p>","PeriodicalId":55150,"journal":{"name":"Fortschritte Der Physik-Progress of Physics","volume":"72 7-8","pages":""},"PeriodicalIF":5.6,"publicationDate":"2024-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141769727","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}
Chris Fields, James F. Glazebrook, Antonino Marcianò
{"title":"Communication Protocols and QECCs from the Perspective of TQFT, Part I: Constructing LOCC Protocols and QECCs from TQFTs","authors":"Chris Fields, James F. Glazebrook, Antonino Marcianò","doi":"10.1002/prop.202400049","DOIUrl":"10.1002/prop.202400049","url":null,"abstract":"<p>Topological quantum field theories (TQFTs) provide a general, minimal-assumption language for describing quantum-state preparation and measurement. They therefore provide a general language in which to express multi-agent communication protocols, e.g., local operations, classical communication (LOCC) protocols. Here, LOCC protocols are constructed using TQFT and it is shown that LOCC protocols generically induce quantum error-correcting codes (QECCs). Using multi-observer scenarios described by quantum Darwinism and Bell/EPR experiments as examples, it is shown how these LOCC-induced QECCs effectively convert entanglement into classical redundancy. In the accompanying Part II, it is shown that such QECCs can be regarded as implementing, or inducing the emergence of, spacetimes on the boundaries between interacting systems. The connection between inter-agent communication and spacetime using BF and Chern-Simons theories, and then using topological M-theory is investigated.</p>","PeriodicalId":55150,"journal":{"name":"Fortschritte Der Physik-Progress of Physics","volume":"72 7-8","pages":""},"PeriodicalIF":5.6,"publicationDate":"2024-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141769728","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}
Fabiano F. Santos, Moisés Bravo-Gaete, Manoel M. Ferreira, Rodolfo Casana
{"title":"Magnetized AdS/BCFT Correspondence in Horndeski Gravity","authors":"Fabiano F. Santos, Moisés Bravo-Gaete, Manoel M. Ferreira, Rodolfo Casana","doi":"10.1002/prop.202400088","DOIUrl":"10.1002/prop.202400088","url":null,"abstract":"<p>This work examines the thermodynamics and hydrodynamics behaviors of a five-dimensional black hole under the influence of an external magnetic field. The solution is the gravity dual to the Anti-de Sitter/Boundary Conformal Field Theory correspondence, enabling the study of properties within an anisotropic fluid framework. Utilizing holographic renormalization, the free energy and the holographic stress tensor residing on the boundary denoted as <span></span><math>\u0000 <semantics>\u0000 <mi>Q</mi>\u0000 <annotation>$Q$</annotation>\u0000 </semantics></math> are computed. Within the fluid/gravity correspondence framework, authors have a class of boundary extensions in <span></span><math>\u0000 <semantics>\u0000 <mi>Q</mi>\u0000 <annotation>$Q$</annotation>\u0000 </semantics></math>, where the stress-energy tensor describes a magnetizing conformal fluid. The characteristics of this special solution as well as its thermodynamic properties, including the bulk and shear viscosity, the square of the speed of sound, as well as the anisotropic effects induced by the magnetic field in the magnetized conformal plasma are discussed.</p>","PeriodicalId":55150,"journal":{"name":"Fortschritte Der Physik-Progress of Physics","volume":"72 7-8","pages":""},"PeriodicalIF":5.6,"publicationDate":"2024-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141576822","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":"Gravastar Model in Krori–Barua Metric Under \u0000 \u0000 \u0000 f\u0000 (\u0000 Q\u0000 )\u0000 \u0000 $f(mathcal {Q})$\u0000 Gravity","authors":"Debasmita Mohanty, Pradyumn K. Sahoo","doi":"10.1002/prop.202400082","DOIUrl":"10.1002/prop.202400082","url":null,"abstract":"<p>In this paper, the characteristics of a gravastar in <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>f</mi>\u0000 <mo>(</mo>\u0000 <mi>Q</mi>\u0000 <mo>)</mo>\u0000 </mrow>\u0000 <annotation>$f(mathcal {Q})$</annotation>\u0000 </semantics></math> gravity, which is upheld by Krori–Barua (KB) metric are explored. The authors have used KB metric for the interior and shell regions of the gravastar. The field equations are deduced by using KB metric. In the outside regions of the gravastar, two regular black hole metrics are taken. Additionally, the Israel junction condition to calculate the potential difference across the thin shell concerning different types of regular black holes, such as Bardeen and Hayward is applied. The physical properties like proper length, entropy, energy, equation of state, and stability are also discussed. </p>","PeriodicalId":55150,"journal":{"name":"Fortschritte Der Physik-Progress of Physics","volume":"72 7-8","pages":""},"PeriodicalIF":5.6,"publicationDate":"2024-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/prop.202400082","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141576830","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}