Pub Date : 2024-11-04DOI: 10.1016/j.aop.2024.169828
F. Bagarello , F. Gargano , L. Saluto
In this paper we construct different classes of coherent and bicoherent states for the graphene tight-binding model in presence of a magnetic field, and for a deformed version where we include a -symmetric chemical potential . In particular, the problems caused by the absence of a suitable ground state for the system is taken into account in the construction of these states, for and for . We introduce ladder operators which work well in our context, and we show, in particular, that there exists a choice of these operators which produce a factorization of the Hamiltonian. The role of broken and unbroken -symmetry is discussed, in connection with the strength of .
在本文中，我们为存在磁场的石墨烯紧密束缚模型以及包含 PT 对称化学势 V 的变形模型构建了不同类别的相干和双相干态，特别是在 V=0 和 V≠0 的情况下，在构建这些态时考虑了系统缺乏合适基态所带来的问题。我们引入了梯形算子，这些算子在我们的语境中非常有效，而且我们特别表明，这些算子的选择可以产生哈密顿的因式分解。我们结合 V 的强度讨论了断裂和未断裂 PT 对称性的作用。
{"title":"Coherent states of graphene layer with and without a PT-symmetric chemical potential","authors":"F. Bagarello , F. Gargano , L. Saluto","doi":"10.1016/j.aop.2024.169828","DOIUrl":"10.1016/j.aop.2024.169828","url":null,"abstract":"<div><div>In this paper we construct different classes of coherent and bicoherent states for the graphene tight-binding model in presence of a magnetic field, and for a deformed version where we include a <span><math><mrow><mi>P</mi><mi>T</mi></mrow></math></span>-symmetric chemical potential <span><math><mi>V</mi></math></span>. In particular, the problems caused by the absence of a suitable ground state for the system is taken into account in the construction of these states, for <span><math><mrow><mi>V</mi><mo>=</mo><mn>0</mn></mrow></math></span> and for <span><math><mrow><mi>V</mi><mo>≠</mo><mn>0</mn></mrow></math></span>. We introduce ladder operators which work well in our context, and we show, in particular, that there exists a choice of these operators which produce a factorization of the Hamiltonian. The role of broken and unbroken <span><math><mrow><mi>P</mi><mi>T</mi></mrow></math></span>-symmetry is discussed, in connection with the strength of <span><math><mi>V</mi></math></span>.</div></div>","PeriodicalId":8249,"journal":{"name":"Annals of Physics","volume":"471 ","pages":"Article 169828"},"PeriodicalIF":3.0,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142651363","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 : 2024-11-01DOI: 10.1016/j.aop.2024.169832
Babak Parvin
A two-level atom is enclosed in a single-mode optical cavity, and the occurring processes in this system have been theoretically examined in the steady-state. In the non-resonance case and in several different instances, the lasing and non-lasing regimes are specified in the semiclassical approximation in the parameter space. The behavior of the system is fully described for the time when there are a small or large number of photons in the cavity. The semiclassical approximation is shown in two different frameworks, and its results are well confirmed by the quantum simulations when there are many photons in the cavity. To observe the change in the behavior of the emitted light near the laser threshold, the second order coherence function and the Fano factor have been used. In explaining the antibunching process, the explicit form of the second order coherence function has been obtained in two different representations. This function is equal in both representations to the lowest order and its findings are in good agreement with the quantum model.
{"title":"Linear and quadratic behaviors in a two-level laser","authors":"Babak Parvin","doi":"10.1016/j.aop.2024.169832","DOIUrl":"10.1016/j.aop.2024.169832","url":null,"abstract":"<div><div>A two-level atom is enclosed in a single-mode optical cavity, and the occurring processes in this system have been theoretically examined in the steady-state. In the non-resonance case and in several different instances, the lasing and non-lasing regimes are specified in the semiclassical approximation in the parameter space. The behavior of the system is fully described for the time when there are a small or large number of photons in the cavity. The semiclassical approximation is shown in two different frameworks, and its results are well confirmed by the quantum simulations when there are many photons in the cavity. To observe the change in the behavior of the emitted light near the laser threshold, the second order coherence function and the Fano factor have been used. In explaining the antibunching process, the explicit form of the second order coherence function has been obtained in two different representations. This function is equal in both representations to the lowest order and its findings are in good agreement with the quantum model.</div></div>","PeriodicalId":8249,"journal":{"name":"Annals of Physics","volume":"471 ","pages":"Article 169832"},"PeriodicalIF":3.0,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142587059","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 : 2024-11-01DOI: 10.1016/j.aop.2024.169830
H.C. Rosu, J. de la Cruz
The singular parametric oscillators obtained from the one-parameter Darboux deformation/ transformation effected upon the classical harmonic oscillator are introduced and discussed in some detail using and as seed solutions. The corresponding Ermakov–Lewis integrability problem of these parametric oscillators is also studied. It is shown that their Ermakov–Lewis invariants do not depend on the deformation parameter and are singularity-free.
{"title":"Singular parametric oscillators from the one-parameter Darboux transformation of the classical harmonic oscillator","authors":"H.C. Rosu, J. de la Cruz","doi":"10.1016/j.aop.2024.169830","DOIUrl":"10.1016/j.aop.2024.169830","url":null,"abstract":"<div><div>The singular parametric oscillators obtained from the one-parameter Darboux deformation/ transformation effected upon the classical harmonic oscillator are introduced and discussed in some detail using <span><math><mrow><mo>sin</mo><mrow><mo>(</mo><msub><mrow><mi>ω</mi></mrow><mrow><mn>0</mn></mrow></msub><mi>t</mi><mo>)</mo></mrow></mrow></math></span> and <span><math><mrow><mo>cos</mo><mrow><mo>(</mo><msub><mrow><mi>ω</mi></mrow><mrow><mn>0</mn></mrow></msub><mi>t</mi><mo>)</mo></mrow></mrow></math></span> as seed solutions. The corresponding Ermakov–Lewis integrability problem of these parametric oscillators is also studied. It is shown that their Ermakov–Lewis invariants do not depend on the deformation parameter and are singularity-free.</div></div>","PeriodicalId":8249,"journal":{"name":"Annals of Physics","volume":"470 ","pages":"Article 169830"},"PeriodicalIF":3.0,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142553860","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 : 2024-11-01DOI: 10.1016/j.aop.2024.169831
Xin Gu , Yuan-Yuan Liu , Hong-Wei Ke , Wen-Du Li , Wu-Sheng Dai
This paper proposes a method for constructing exactly solvable time-dependent oscillator families based on the invariant operator method and the duality method. An exactly solvable time-dependent oscillator family contains an infinite number of exactly solvable time-dependent oscillators. As a byproduct, we also construct exactly solvable Ermakov–Pinney equation families.
{"title":"Exactly solvable time-dependent oscillator family","authors":"Xin Gu , Yuan-Yuan Liu , Hong-Wei Ke , Wen-Du Li , Wu-Sheng Dai","doi":"10.1016/j.aop.2024.169831","DOIUrl":"10.1016/j.aop.2024.169831","url":null,"abstract":"<div><div>This paper proposes a method for constructing exactly solvable time-dependent oscillator families based on the invariant operator method and the duality method. An exactly solvable time-dependent oscillator family contains an infinite number of exactly solvable time-dependent oscillators. As a byproduct, we also construct exactly solvable Ermakov–Pinney equation families.</div></div>","PeriodicalId":8249,"journal":{"name":"Annals of Physics","volume":"470 ","pages":"Article 169831"},"PeriodicalIF":3.0,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142553861","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 : 2024-11-01DOI: 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}
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