Pub Date : 2023-06-30DOI: 10.1142/S0218271823500633
A. Iorio, L. Smaldone
Space and matter may both be manifestations of a single fundamental quantum dynamics, as it may become evident during black-hole evaporation. Inspired by the fact that quantum electrodynamics underlies the classical theory of elasticity, that in turn has a natural and well-known geometric description in terms of curvature and torsion, related to topological defects, here we move some necessary steps to find the map from such fundamental quantum level to the emergent level of classical space and quantum matter. We proceed by adapting the boson transformation method of standard quantum field theory to the quantum gravity fundamental scenario and successfully obtain the emergence of curvature and torsion, our main focus here. In doing so, we have been able to overcome difficult issues of interpretation, related to the Goldstone modes for rotational symmetry. In fact, we have been able to apply the boson transformation method to disclinations, to relate them to the spin structure and to give an heuristic derivation of the matter field equation on curved space. We also improve results of previous work on the emergence of geometric tensors from elasticity theory, as the non-Abelian contributions to the torsion and curvature tensors, postulated in those papers, here emerge naturally. More work is necessary to identify the type of gravity theories one can obtain in this way.
{"title":"Quantum black holes as classical space factories","authors":"A. Iorio, L. Smaldone","doi":"10.1142/S0218271823500633","DOIUrl":"https://doi.org/10.1142/S0218271823500633","url":null,"abstract":"Space and matter may both be manifestations of a single fundamental quantum dynamics, as it may become evident during black-hole evaporation. Inspired by the fact that quantum electrodynamics underlies the classical theory of elasticity, that in turn has a natural and well-known geometric description in terms of curvature and torsion, related to topological defects, here we move some necessary steps to find the map from such fundamental quantum level to the emergent level of classical space and quantum matter. We proceed by adapting the boson transformation method of standard quantum field theory to the quantum gravity fundamental scenario and successfully obtain the emergence of curvature and torsion, our main focus here. In doing so, we have been able to overcome difficult issues of interpretation, related to the Goldstone modes for rotational symmetry. In fact, we have been able to apply the boson transformation method to disclinations, to relate them to the spin structure and to give an heuristic derivation of the matter field equation on curved space. We also improve results of previous work on the emergence of geometric tensors from elasticity theory, as the non-Abelian contributions to the torsion and curvature tensors, postulated in those papers, here emerge naturally. More work is necessary to identify the type of gravity theories one can obtain in this way.","PeriodicalId":50307,"journal":{"name":"International Journal of Modern Physics D","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46412926","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2023-06-28DOI: 10.1142/s0218271823500657
J. Sadeghi, Saeed Noori Gashti, M. Alipour, M. A. S. Afshar
One of the most important issues in cosmology is the study of a series of hypothetical objects called wormholes. Recently, researchers have studied these hypothetical objects under different conditions. In this paper, we aim to evaluate the traversable wormhole according to a modified [Formula: see text] gravitational model, specifically [Formula: see text], from the perspective of two essential functions in wormhole structure: shape and redshift function. These hypothetical objects can solve Einstein’s equations by tolerating the violation of null energy conditions (NEC). With respect to these concepts, we examine various energy conditions such as the NEC, weak energy condition (WEC), dominant energy condition (DEC) and strong energy condition (SEC) using radial pressure, tangential pressure and energy density obtained from the wormhole equations. Finally, we evaluate different energy conditions by plotting some figures and checking for satisfaction or violation. We will analyze the results and present the conclusions in tables.
{"title":"Energy conditions of traversable wormhole in the deformed f(R) gravitational model","authors":"J. Sadeghi, Saeed Noori Gashti, M. Alipour, M. A. S. Afshar","doi":"10.1142/s0218271823500657","DOIUrl":"https://doi.org/10.1142/s0218271823500657","url":null,"abstract":"One of the most important issues in cosmology is the study of a series of hypothetical objects called wormholes. Recently, researchers have studied these hypothetical objects under different conditions. In this paper, we aim to evaluate the traversable wormhole according to a modified [Formula: see text] gravitational model, specifically [Formula: see text], from the perspective of two essential functions in wormhole structure: shape and redshift function. These hypothetical objects can solve Einstein’s equations by tolerating the violation of null energy conditions (NEC). With respect to these concepts, we examine various energy conditions such as the NEC, weak energy condition (WEC), dominant energy condition (DEC) and strong energy condition (SEC) using radial pressure, tangential pressure and energy density obtained from the wormhole equations. Finally, we evaluate different energy conditions by plotting some figures and checking for satisfaction or violation. We will analyze the results and present the conclusions in tables.","PeriodicalId":50307,"journal":{"name":"International Journal of Modern Physics D","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45568485","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2023-06-26DOI: 10.1142/s0218271823420105
Ashu Kushwaha, S. Malik, S. Shankaranarayanan
{"title":"Fast Radio Bursts signal high-frequency gravitational waves","authors":"Ashu Kushwaha, S. Malik, S. Shankaranarayanan","doi":"10.1142/s0218271823420105","DOIUrl":"https://doi.org/10.1142/s0218271823420105","url":null,"abstract":"","PeriodicalId":50307,"journal":{"name":"International Journal of Modern Physics D","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48786290","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2023-06-23DOI: 10.1142/s0218271823500621
A. Samaddar, S. S. Singh, Md Khurshid Alam
We investigated the stability condition of [Formula: see text] gravity theory with interacting and noninteracting models by using dynamical system. We assume the [Formula: see text] function as [Formula: see text], where [Formula: see text] is the free parameter. We evaluated the critical points for this model and examined the stability behavior. We found two stable critical points for interacting model. The phase plots for this system are examined and the physical interpretation is discussed. We illustrate all the cosmological parameters such as [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text] at each fixed point and compare the parameters with observational values. Further, we assume hybrid scale factor and the equation of redshift and time is [Formula: see text]. We transform all the parameters in terms of redshift by using this equation and examine the behavior of these parameters. Our model represents the accelerated expansion of the universe. The energy conditions are examined in terms of redshift and strong energy conditions are not satisfied for the model. We also find the statefinder parameters [Formula: see text] in terms of z and discuss the nature of r–s and r–q plane. For both pairs [Formula: see text] and [Formula: see text] our model represents the [Formula: see text]CDM model. Hence, we determine that our [Formula: see text] model is stable and it satisfies all the observational values.
用动力系统方法研究了引力理论在相互作用和非相互作用模型下的稳定性条件。我们假设[Formula: see text]函数为[Formula: see text]，其中[Formula: see text]是自由参数。我们评估了该模型的临界点，并检查了稳定性行为。我们找到了相互作用模型的两个稳定临界点。研究了该系统的相图，并讨论了物理解释。我们举例说明了每个固定点的所有宇宙学参数，如[公式:见文]、[公式:见文]、[公式:见文]和[公式:见文]，并将参数与观测值进行了比较。进一步，我们假设混合尺度因子和红移与时间的方程为[公式:见文]。我们用这个方程将所有参数用红移的形式进行变换，并检验这些参数的行为。我们的模型代表了宇宙的加速膨胀。从红移角度考察了能量条件，发现模型不满足强能量条件。我们还找到了用z表示的寻态器参数[公式:见文]，并讨论了r-s和r-q平面的性质。对于这两对[公式:见文本]和[公式:见文本]，我们的模型代表[公式:见文本]CDM模型。因此，我们确定我们的[公式:见文]模型是稳定的，它满足所有观测值。
{"title":"Dynamical system approach of interacting dark energy models with minimally coupled scalar field","authors":"A. Samaddar, S. S. Singh, Md Khurshid Alam","doi":"10.1142/s0218271823500621","DOIUrl":"https://doi.org/10.1142/s0218271823500621","url":null,"abstract":"We investigated the stability condition of [Formula: see text] gravity theory with interacting and noninteracting models by using dynamical system. We assume the [Formula: see text] function as [Formula: see text], where [Formula: see text] is the free parameter. We evaluated the critical points for this model and examined the stability behavior. We found two stable critical points for interacting model. The phase plots for this system are examined and the physical interpretation is discussed. We illustrate all the cosmological parameters such as [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text] at each fixed point and compare the parameters with observational values. Further, we assume hybrid scale factor and the equation of redshift and time is [Formula: see text]. We transform all the parameters in terms of redshift by using this equation and examine the behavior of these parameters. Our model represents the accelerated expansion of the universe. The energy conditions are examined in terms of redshift and strong energy conditions are not satisfied for the model. We also find the statefinder parameters [Formula: see text] in terms of z and discuss the nature of r–s and r–q plane. For both pairs [Formula: see text] and [Formula: see text] our model represents the [Formula: see text]CDM model. Hence, we determine that our [Formula: see text] model is stable and it satisfies all the observational values.","PeriodicalId":50307,"journal":{"name":"International Journal of Modern Physics D","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48712904","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2023-06-20DOI: 10.1142/s0218271823420087
A. Goswami
{"title":"Non-Linear Sigma Models in Inflationary Cosmology","authors":"A. Goswami","doi":"10.1142/s0218271823420087","DOIUrl":"https://doi.org/10.1142/s0218271823420087","url":null,"abstract":"","PeriodicalId":50307,"journal":{"name":"International Journal of Modern Physics D","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42171618","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2023-06-20DOI: 10.1142/s0218271823500694
S. Kibaroğlu
{"title":"Cosmological application of the Maxwell gravity","authors":"S. Kibaroğlu","doi":"10.1142/s0218271823500694","DOIUrl":"https://doi.org/10.1142/s0218271823500694","url":null,"abstract":"","PeriodicalId":50307,"journal":{"name":"International Journal of Modern Physics D","volume":"26 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"63903099","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2023-06-20DOI: 10.1142/s0218271823500682
Abdel Nasser Tawfik, Tahia F. Dabash
{"title":"Born Reciprocity and Discritized Finsler Structure: An Approach to Quantize GR Curvature Tensors on 3-Sphere","authors":"Abdel Nasser Tawfik, Tahia F. Dabash","doi":"10.1142/s0218271823500682","DOIUrl":"https://doi.org/10.1142/s0218271823500682","url":null,"abstract":"","PeriodicalId":50307,"journal":{"name":"International Journal of Modern Physics D","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44395825","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2023-06-13DOI: 10.1142/s0218271823420038
T. Boekholt, S. P. Portegies Zwart, D. Heggie
Dynamical chaos is a fundamental manifestation of gravity in astrophysical, many-body systems. The spectrum of Lyapunov exponents quantifies the associated exponential response to small perturbations. Analytical derivations of these exponents are critical for understanding the stability and predictability of observed systems. This essay presents a new model for chaos in systems with eccentric and crossing orbits. Here, exponential divergence is not a continuous process but rather the cumulative effect of an ever-increasing linear response driven by discrete events at regular intervals, i.e., punctuated chaos. We show that long-lived systems with punctuated chaos can magnify Planck length perturbations to astronomical scales within their lifetime, rendering them fundamentally indeterministic.
{"title":"Punctuated Chaos and Indeterminism in Self-gravitating Many-body Systems","authors":"T. Boekholt, S. P. Portegies Zwart, D. Heggie","doi":"10.1142/s0218271823420038","DOIUrl":"https://doi.org/10.1142/s0218271823420038","url":null,"abstract":"Dynamical chaos is a fundamental manifestation of gravity in astrophysical, many-body systems. The spectrum of Lyapunov exponents quantifies the associated exponential response to small perturbations. Analytical derivations of these exponents are critical for understanding the stability and predictability of observed systems. This essay presents a new model for chaos in systems with eccentric and crossing orbits. Here, exponential divergence is not a continuous process but rather the cumulative effect of an ever-increasing linear response driven by discrete events at regular intervals, i.e., punctuated chaos. We show that long-lived systems with punctuated chaos can magnify Planck length perturbations to astronomical scales within their lifetime, rendering them fundamentally indeterministic.","PeriodicalId":50307,"journal":{"name":"International Journal of Modern Physics D","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44788641","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2023-06-13DOI: 10.1142/s0218271823500670
Nisha Godani, Shubham Kala
{"title":"A New Class of Generalised Ellis-Bronnikov Wormhole in Asymptotically Safe Gravity","authors":"Nisha Godani, Shubham Kala","doi":"10.1142/s0218271823500670","DOIUrl":"https://doi.org/10.1142/s0218271823500670","url":null,"abstract":"","PeriodicalId":50307,"journal":{"name":"International Journal of Modern Physics D","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48539802","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2023-06-09DOI: 10.1142/s0218271823500669
M. Ghosh, S. Chattopadhyay
{"title":"Constraining the bounce realization with holographic background and analytical exploration of the consequences in a modified gravity framework","authors":"M. Ghosh, S. Chattopadhyay","doi":"10.1142/s0218271823500669","DOIUrl":"https://doi.org/10.1142/s0218271823500669","url":null,"abstract":"","PeriodicalId":50307,"journal":{"name":"International Journal of Modern Physics D","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46278809","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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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