Pub Date : 2024-11-01DOI: 10.1016/j.aop.2024.169829
Saurya Das , S. Shajidul Haque , Seturumane Tema
A bouncing Universe avoids the big-bang singularity. Using the time-like and null Raychaudhuri equations, we explore whether the bounce near the big-bang, within a broad spectrum of modified theories of gravity, allows for cosmologically relevant power-law solutions under reasonable physical conditions. Our study shows that certain modified theories of gravity, such as Stelle gravity, do not demonstrate singularity resolution under any reasonable conditions, while others including gravity and Brans–Dicke theory can demonstrate singularity resolution under suitable conditions. For these theories, we show that the accelerating solution is slightly favored over ekypyrosis.
{"title":"Cosmological singularity and power-law solutions in modified gravity","authors":"Saurya Das , S. Shajidul Haque , Seturumane Tema","doi":"10.1016/j.aop.2024.169829","DOIUrl":"10.1016/j.aop.2024.169829","url":null,"abstract":"<div><div>A bouncing Universe avoids the big-bang singularity. Using the time-like and null Raychaudhuri equations, we explore whether the bounce near the big-bang, within a broad spectrum of modified theories of gravity, allows for cosmologically relevant power-law solutions under reasonable physical conditions. Our study shows that certain modified theories of gravity, such as Stelle gravity, do not demonstrate singularity resolution under any reasonable conditions, while others including <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>R</mi><mo>)</mo></mrow></mrow></math></span> gravity and Brans–Dicke theory can demonstrate singularity resolution under suitable conditions. For these theories, we show that the accelerating solution is slightly favored over ekypyrosis.</div></div>","PeriodicalId":8249,"journal":{"name":"Annals of Physics","volume":"470 ","pages":"Article 169829"},"PeriodicalIF":3.0,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142571522","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}
Pub Date : 2024-11-01DOI: 10.1016/j.aop.2024.169833
M.H. Macêdo , J. Furtado , G. Alencar , R.R. Landim
In this study, we investigate the thermodynamic properties and quasinormal modes of Dymnikova black holes within the context of higher dimensions in Einstein’s general theory of relativity. We calculate the thermodynamic parameters, including the Hawking temperature and heat capacity, which allowed us to investigate the black hole’s stability. Lastly the quasinormal modes with the WKB formula were calculated.
{"title":"Thermodynamics and quasinormal modes of the Dymnikova black hole in higher dimensions","authors":"M.H. Macêdo , J. Furtado , G. Alencar , R.R. Landim","doi":"10.1016/j.aop.2024.169833","DOIUrl":"10.1016/j.aop.2024.169833","url":null,"abstract":"<div><div>In this study, we investigate the thermodynamic properties and quasinormal modes of Dymnikova black holes within the context of higher dimensions in Einstein’s general theory of relativity. We calculate the thermodynamic parameters, including the Hawking temperature and heat capacity, which allowed us to investigate the black hole’s stability. Lastly the quasinormal modes with the WKB formula were calculated.</div></div>","PeriodicalId":8249,"journal":{"name":"Annals of Physics","volume":"471 ","pages":"Article 169833"},"PeriodicalIF":3.0,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142587058","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}
Pub Date : 2024-10-31DOI: 10.1016/j.aop.2024.169835
Seng Ghee Tan , Che Chun Huang , Mansoor B.A. Jalil , Zhuobin Siu
We provide a general formulation of the spin-orbit coupling on a 2D curved surface. Considering the wide applicability of spin-orbit effect in spinor-based condensed matter physics, a general spin-orbit formulation could aid the study of spintronics, Dirac graphene, topological systems, and quantum information on curved surfaces. Particular attention is then devoted to the development of an important spin-orbit quantity known as the spin-orbit torque. As devices trend smaller in dimension, the physics of local geometries on spin-orbit torque, hence spin and magnetic dynamics shall not be neglected. We derived the general expression of a spin-orbit anisotropy field for the curved surfaces and provided explicit solutions in the special contexts of the spherical, cylindrical and flat coordinates. Our expressions allow spin-orbit anisotropy fields and hence spin-orbit torque to be computed over the entire surfaces of devices of any geometry.
{"title":"Spin orbit torque on a curved surface","authors":"Seng Ghee Tan , Che Chun Huang , Mansoor B.A. Jalil , Zhuobin Siu","doi":"10.1016/j.aop.2024.169835","DOIUrl":"10.1016/j.aop.2024.169835","url":null,"abstract":"<div><div>We provide a general formulation of the spin-orbit coupling on a 2D curved surface. Considering the wide applicability of spin-orbit effect in spinor-based condensed matter physics, a general spin-orbit formulation could aid the study of spintronics, Dirac graphene, topological systems, and quantum information on curved surfaces. Particular attention is then devoted to the development of an important spin-orbit quantity known as the spin-orbit torque. As devices trend smaller in dimension, the physics of local geometries on spin-orbit torque, hence spin and magnetic dynamics shall not be neglected. We derived the general expression of a spin-orbit anisotropy field for the curved surfaces and provided explicit solutions in the special contexts of the spherical, cylindrical and flat coordinates. Our expressions allow spin-orbit anisotropy fields and hence spin-orbit torque to be computed over the entire surfaces of devices of any geometry.</div></div>","PeriodicalId":8249,"journal":{"name":"Annals of Physics","volume":"471 ","pages":"Article 169835"},"PeriodicalIF":3.0,"publicationDate":"2024-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142651356","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}
Pub Date : 2024-10-28DOI: 10.1016/j.aop.2024.169827
David Dudal , Thomas Oosthuyse , Sebbe Stouten , Aaron Gobeyn , Bruno W. Mintz
We reconsider four-dimensional scalar field theory in presence of Robin boundary conditions on two parallel plates. These boundary conditions are directly imposed in the path integral definition of the theory via auxiliary fields living on the plates. We discuss how this leads to boundary corrections to the standard energy momentum tensor operator. Via a dimensional reduction to an effective three-dimensional boundary theory, we compute the Casimir energy in terms of the plate separation and the two Robin parameters, as well as the scalar field propagator in the presence of the plates. Coincidentally, the boundary contribution vanishes in the expectation value for the vacuum energy, thereby giving results in full accordance with other energy expressions in the literature for the same setup. We also discuss for which values of the Robin parameters this energy is real-valued.
{"title":"Scalar field theory under Robin boundary conditions: Two-point function and energy–momentum tensor","authors":"David Dudal , Thomas Oosthuyse , Sebbe Stouten , Aaron Gobeyn , Bruno W. Mintz","doi":"10.1016/j.aop.2024.169827","DOIUrl":"10.1016/j.aop.2024.169827","url":null,"abstract":"<div><div>We reconsider four-dimensional scalar field theory in presence of Robin boundary conditions on two parallel plates. These boundary conditions are directly imposed in the path integral definition of the theory via auxiliary fields living on the plates. We discuss how this leads to boundary corrections to the standard energy momentum tensor operator. Via a dimensional reduction to an effective three-dimensional boundary theory, we compute the Casimir energy in terms of the plate separation and the two Robin parameters, as well as the scalar field propagator in the presence of the plates. Coincidentally, the boundary contribution vanishes in the expectation value for the vacuum energy, thereby giving results in full accordance with other energy expressions in the literature for the same setup. We also discuss for which values of the Robin parameters this energy is real-valued.</div></div>","PeriodicalId":8249,"journal":{"name":"Annals of Physics","volume":"470 ","pages":"Article 169827"},"PeriodicalIF":3.0,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142532515","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}
Pub Date : 2024-10-18DOI: 10.1016/j.aop.2024.169826
Fariba Kafikang , Hassan Hassanabadi , Won Sang Chung , Filip Studnička
In this article, gravity is considered with deviation and we solved the Lane–Emden equation using this deviation, first, we calculated the pressure and potential due to gravity, and considering the density resulting from solving this equation, we obtained the radius of the white dwarf in different states. We obtained the ordinary cases when the deformation parameter goes to zero.
{"title":"Investigation of the white dwarfs based on deformed Lane–Emden equation","authors":"Fariba Kafikang , Hassan Hassanabadi , Won Sang Chung , Filip Studnička","doi":"10.1016/j.aop.2024.169826","DOIUrl":"10.1016/j.aop.2024.169826","url":null,"abstract":"<div><div>In this article, gravity is considered with deviation and we solved the Lane–Emden equation using this deviation, first, we calculated the pressure and potential due to gravity, and considering the density resulting from solving this equation, we obtained the radius of the white dwarf in different states. We obtained the ordinary cases when the deformation parameter goes to zero.</div></div>","PeriodicalId":8249,"journal":{"name":"Annals of Physics","volume":"470 ","pages":"Article 169826"},"PeriodicalIF":3.0,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142532654","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}
Pub Date : 2024-10-16DOI: 10.1016/j.aop.2024.169825
Zhen-Dong Wei , Wei Han , Ying-Jie Zhang , Zhong-Xiao Man , Yun-Jie Xia , Heng Fan
By considering two qubits respectively coupled with two independent reservoirs and ignoring the interaction between them, two different cases are studied in two models: only one qubit accelerates and hovers near the event horizon or both two qubits accelerate and hover near the event horizon. The first model is given by referring to the damping Jaynes–Cummings model with a reservoir described by Lorentzian spectral density. And the second model is a pure dephasing model with a reservoir described by Ohmic spectral density. We investigate the impact of acceleration and Hawking temperature on the non-Markovianity and the quantum speed limit time of a two-qubit open quantum system. Through the numerical calculation, it is found that for these two models, by reducing the acceleration of qubits and the Hawking temperature outside the event horizon, the non-Markovianity of the dynamic process of the quantum system in the Schwarzschild space–time can be enhanced until it approaches the non-Markovianity when both qubits are in the inertial frame. However, we find that in the first model, the evolution speed of quantum state can be accelerated with decreasing acceleration and Hawking temperature. While in the second model, the quantum state evolution speed can be accelerated with increasing acceleration and Hawking temperature. For both models, the evolution speed of the quantum state of the system in the Markovian dynamics can still be accelerated.
{"title":"Non-Markovian dynamics control of an open quantum system in a Schwarzschild space–time","authors":"Zhen-Dong Wei , Wei Han , Ying-Jie Zhang , Zhong-Xiao Man , Yun-Jie Xia , Heng Fan","doi":"10.1016/j.aop.2024.169825","DOIUrl":"10.1016/j.aop.2024.169825","url":null,"abstract":"<div><div>By considering two qubits respectively coupled with two independent reservoirs and ignoring the interaction between them, two different cases are studied in two models: only one qubit accelerates and hovers near the event horizon or both two qubits accelerate and hover near the event horizon. The first model is given by referring to the damping Jaynes–Cummings model with a reservoir described by Lorentzian spectral density. And the second model is a pure dephasing model with a reservoir described by Ohmic spectral density. We investigate the impact of acceleration and Hawking temperature on the non-Markovianity and the quantum speed limit time of a two-qubit open quantum system. Through the numerical calculation, it is found that for these two models, by reducing the acceleration of qubits and the Hawking temperature outside the event horizon, the non-Markovianity of the dynamic process of the quantum system in the Schwarzschild space–time can be enhanced until it approaches the non-Markovianity when both qubits are in the inertial frame. However, we find that in the first model, the evolution speed of quantum state can be accelerated with decreasing acceleration and Hawking temperature. While in the second model, the quantum state evolution speed can be accelerated with increasing acceleration and Hawking temperature. For both models, the evolution speed of the quantum state of the system in the Markovian dynamics can still be accelerated.</div></div>","PeriodicalId":8249,"journal":{"name":"Annals of Physics","volume":"470 ","pages":"Article 169825"},"PeriodicalIF":3.0,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142532514","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}
Motivated by recent interest in the search for generating potentials for which the underlying Schrödinger equation is solvable, we report in the recent work several situations when a zero-energy state becomes bound depending on certain restrictions on the coupling constants that define the potential. In this regard, we present evidence of the existence of regular zero-energy normalizable solutions for a system of quasi-exactly solvable (QES) potentials that correspond to the rationally extended many-body truncated Calogero–Sutherland (TCS) model. Our procedure is based upon the use of the standard potential group approach with an underlying structure that utilizes a point canonical transformation with three distinct types of potentials emerging having the same eigenvalues while their common properties are subjected to the evaluation of the relevant wave functions. These cases are treated individually by suitably restricting the coupling parameters.
{"title":"Generating QES potentials supporting zero energy normalizable states for an extended class of truncated Calogero Sutherland model","authors":"Satish Yadav , Sudhanshu Shekhar , Bijan Bagchi , Bhabani Prasad Mandal","doi":"10.1016/j.aop.2024.169822","DOIUrl":"10.1016/j.aop.2024.169822","url":null,"abstract":"<div><div>Motivated by recent interest in the search for generating potentials for which the underlying Schrödinger equation is solvable, we report in the recent work several situations when a zero-energy state becomes bound depending on certain restrictions on the coupling constants that define the potential. In this regard, we present evidence of the existence of regular zero-energy normalizable solutions for a system of quasi-exactly solvable (QES) potentials that correspond to the rationally extended many-body truncated Calogero–Sutherland (TCS) model. Our procedure is based upon the use of the standard potential group approach with an underlying <span><math><mrow><mi>s</mi><mi>o</mi><mrow><mo>(</mo><mn>2</mn><mo>,</mo><mn>1</mn><mo>)</mo></mrow></mrow></math></span> structure that utilizes a point canonical transformation with three distinct types of potentials emerging having the same eigenvalues while their common properties are subjected to the evaluation of the relevant wave functions. These cases are treated individually by suitably restricting the coupling parameters.</div></div>","PeriodicalId":8249,"journal":{"name":"Annals of Physics","volume":"470 ","pages":"Article 169822"},"PeriodicalIF":3.0,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142532653","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}
Pub Date : 2024-10-11DOI: 10.1016/j.aop.2024.169820
C.A.I. Florián, Rodolfo Casana, André C. Santos
We investigate the existence of self-dual configurations in the restricted gauged baby Skyrme model enlarged with a –symmetry, which introduces a real scalar field. For such a purpose, we implement the Bogomol’nyi procedure that provides a lower bound for the energy and the respective self-dual equations whose solutions saturate such a bound. Aiming to solve the self-dual equations, we specifically focused on a class of topological structures called compacton. We obtain the corresponding numerical solutions within two distinct scenarios, each defined by a scalar field, allowing us to describe different magnetic media. Finally, we analyze how the compacton profiles change when immersed in each medium.
{"title":"Self-dual compact gauged baby skyrmions in a continuous medium","authors":"C.A.I. Florián, Rodolfo Casana, André C. Santos","doi":"10.1016/j.aop.2024.169820","DOIUrl":"10.1016/j.aop.2024.169820","url":null,"abstract":"<div><div>We investigate the existence of self-dual configurations in the restricted gauged baby Skyrme model enlarged with a <span><math><msub><mrow><mi>Z</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span>–symmetry, which introduces a real scalar field. For such a purpose, we implement the Bogomol’nyi procedure that provides a lower bound for the energy and the respective self-dual equations whose solutions saturate such a bound. Aiming to solve the self-dual equations, we specifically focused on a class of topological structures called compacton. We obtain the corresponding numerical solutions within two distinct scenarios, each defined by a scalar field, allowing us to describe different magnetic media. Finally, we analyze how the compacton profiles change when immersed in each medium.</div></div>","PeriodicalId":8249,"journal":{"name":"Annals of Physics","volume":"470 ","pages":"Article 169820"},"PeriodicalIF":3.0,"publicationDate":"2024-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142532651","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}
Pub Date : 2024-10-11DOI: 10.1016/j.aop.2024.169823
H.O. Cildiroglu
Exploring the time-dependent characteristics of AB-type effects holds significant importance in contemporary physics and its practical applications. Here, we delve into the investigation of time-dependent topological effects emerging in AB-type experimental setups. We first analyse the topological effects on magnetic dipoles moving in closed trajectories around the time-varying magnetic field source solenoid, then on electrical dipoles around a time-varying electric field source in 2+1 dimensions without any approximation. Last, we discuss the characteristics of the topological effects by considering the identity and dualities between phases from an integrated perspective.
探索 AB 型效应的时间相关特性在当代物理学及其实际应用中具有重要意义。在此，我们将深入研究 AB 型实验装置中出现的随时间变化的拓扑效应。我们首先分析了围绕时变磁场源螺线管以封闭轨迹运动的磁偶极子的拓扑效应，然后分析了在 2+1 维中围绕时变电场源运动的电偶极子的拓扑效应。最后，我们从综合角度考虑了相间的同一性和对偶性，讨论了拓扑效应的特征。
{"title":"Time-dependent Aharonov-Bohm type topological effects on dipoles","authors":"H.O. Cildiroglu","doi":"10.1016/j.aop.2024.169823","DOIUrl":"10.1016/j.aop.2024.169823","url":null,"abstract":"<div><div>Exploring the time-dependent characteristics of AB-type effects holds significant importance in contemporary physics and its practical applications. Here, we delve into the investigation of time-dependent topological effects emerging in AB-type experimental setups. We first analyse the topological effects on magnetic dipoles moving in closed trajectories around the time-varying magnetic field source solenoid, then on electrical dipoles around a time-varying electric field source in 2+1 dimensions without any approximation. Last, we discuss the characteristics of the topological effects by considering the identity and dualities between phases from an integrated perspective.</div></div>","PeriodicalId":8249,"journal":{"name":"Annals of Physics","volume":"470 ","pages":"Article 169823"},"PeriodicalIF":3.0,"publicationDate":"2024-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142445932","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}
Pub Date : 2024-10-11DOI: 10.1016/j.aop.2024.169821
Shalin Jose, Anil Shaji
We study the open quantum dynamics using the language of dynamical maps of a two-level particle detector that starts accelerating through Minkowski vacuum weakly coupled to a massless scalar field. We consider a detector with non-zero size and study its time evolution for the case where it is initially in inertial motion and subsequently a constant acceleration is switched on for a finite time. We study the dynamical maps that describe the evolution of such a system and show that the dynamics is not completely positive (NCP). The inertial motion prior to the acceleration can entangle the detector and field leading to the NCP dynamics. We examine the nature of the open dynamics during the accelerated phase as a function of the duration of prior inertial motion and the magnitude of the acceleration.
{"title":"Dynamical maps for accelerating detectors","authors":"Shalin Jose, Anil Shaji","doi":"10.1016/j.aop.2024.169821","DOIUrl":"10.1016/j.aop.2024.169821","url":null,"abstract":"<div><div>We study the open quantum dynamics using the language of dynamical maps of a two-level particle detector that starts accelerating through Minkowski vacuum weakly coupled to a massless scalar field. We consider a detector with non-zero size and study its time evolution for the case where it is initially in inertial motion and subsequently a constant acceleration is switched on for a finite time. We study the dynamical maps that describe the evolution of such a system and show that the dynamics is not completely positive (NCP). The inertial motion prior to the acceleration can entangle the detector and field leading to the NCP dynamics. We examine the nature of the open dynamics during the accelerated phase as a function of the duration of prior inertial motion and the magnitude of the acceleration.</div></div>","PeriodicalId":8249,"journal":{"name":"Annals of Physics","volume":"470 ","pages":"Article 169821"},"PeriodicalIF":3.0,"publicationDate":"2024-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142532652","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}
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