Pub Date : 2025-12-11DOI: 10.1088/1361-6382/ae255f
Min-Seok Seo
String compactification in the framework of the low energy effective supergravity requires the perturbative control in both the large volume and the weak coupling expansions. However, when the complex structure moduli couple to some lattice structure, the Sp symmetry of the tree level Kähler potential allows the correction to the Kähler potential to diverge in the large field limit of the complex structure moduli, resulting in the breakdown of the perturbative control. Here the lattice structure naturally appears in the presence of a tower of states like the Kaluza–Klein (KK) or the string modes, an essential ingredient of the distance conjecture. The similar situation can be found from the axio-dilaton contribution to the corrected Kähler potential, where the SL symmetry as well as the coupling between the axio-dilaton and the lattice structure allow the correction to diverge in the weak coupling limit. In order to keep the perturbative control, the values of the complex structure moduli as well as the dilaton must have the upper bound, which is determined by the volume of the internal manifold and the string coupling constant, hence the KK and the string mass scales. The form of the bounds are quite similar to that given by the distance conjecture, both prevents the descent of a tower of states.
{"title":"Bounds on complex structure moduli values for perturbative control","authors":"Min-Seok Seo","doi":"10.1088/1361-6382/ae255f","DOIUrl":"https://doi.org/10.1088/1361-6382/ae255f","url":null,"abstract":"String compactification in the framework of the low energy effective supergravity requires the perturbative control in both the large volume and the weak coupling expansions. However, when the complex structure moduli couple to some lattice structure, the Sp symmetry of the tree level Kähler potential allows the correction to the Kähler potential to diverge in the large field limit of the complex structure moduli, resulting in the breakdown of the perturbative control. Here the lattice structure naturally appears in the presence of a tower of states like the Kaluza–Klein (KK) or the string modes, an essential ingredient of the distance conjecture. The similar situation can be found from the axio-dilaton contribution to the corrected Kähler potential, where the SL symmetry as well as the coupling between the axio-dilaton and the lattice structure allow the correction to diverge in the weak coupling limit. In order to keep the perturbative control, the values of the complex structure moduli as well as the dilaton must have the upper bound, which is determined by the volume of the internal manifold and the string coupling constant, hence the KK and the string mass scales. The form of the bounds are quite similar to that given by the distance conjecture, both prevents the descent of a tower of states.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"145 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145717563","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 : 2025-12-10DOI: 10.1088/1361-6382/ae2415
Chad Henshaw, Jacob Lange, Peter Lott, Richard O’Shaughnessy and Laura Cadonati
Systems of two black holes with unbound orbits can produce a diverse array of gravitational wave signals with rich morphology. This parameter space encompasses both hyperbolic orbit scattering events and dynamical captures, including zoom-whirl orbits with multiple flybys and direct plunge mergers. These signals challenge traditional parameter estimation infrastructure, which is largely optimized for quasicircular inspiral binaries. In this work we discuss the adaptation of the Rapid Iterative FiTting (RIFT) algorithm to this problem using the TEOBResumSDALI waveform model which can simulate generic orbits. We present results from a study of simulated signals emulating a scatter and plunge event, utilizing the design sensitivity of the forthcoming Cosmic Explorer interferometer. Our analysis demonstrates that RIFT accurately recovers the mass, spins, and hyperbolic orbit parameters: the system energy and angular momentum defined at a fiducial initial separation.
{"title":"Parameter estimation of gravitational waves from hyperbolic black hole encounters","authors":"Chad Henshaw, Jacob Lange, Peter Lott, Richard O’Shaughnessy and Laura Cadonati","doi":"10.1088/1361-6382/ae2415","DOIUrl":"https://doi.org/10.1088/1361-6382/ae2415","url":null,"abstract":"Systems of two black holes with unbound orbits can produce a diverse array of gravitational wave signals with rich morphology. This parameter space encompasses both hyperbolic orbit scattering events and dynamical captures, including zoom-whirl orbits with multiple flybys and direct plunge mergers. These signals challenge traditional parameter estimation infrastructure, which is largely optimized for quasicircular inspiral binaries. In this work we discuss the adaptation of the Rapid Iterative FiTting (RIFT) algorithm to this problem using the TEOBResumSDALI waveform model which can simulate generic orbits. We present results from a study of simulated signals emulating a scatter and plunge event, utilizing the design sensitivity of the forthcoming Cosmic Explorer interferometer. Our analysis demonstrates that RIFT accurately recovers the mass, spins, and hyperbolic orbit parameters: the system energy and angular momentum defined at a fiducial initial separation.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"110 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145711408","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 : 2025-12-10DOI: 10.1088/1361-6382/ae2416
Carlos Silva
In this paper, we propose a relationship between the so-called Hubble–Lemaî tre constant H0 and the holographic complexity related to the emergence of spacetime in quantum gravity. Such a result can represent an important step to understanding the Hubble tension by introducing a quantum gravity perspective for cosmological observations, regarding the degree of quantum complexity we measure around us.
{"title":"Holographic complexity and the Hubble tension: a quantum gravity portrayal for the large scale structure of the cosmos","authors":"Carlos Silva","doi":"10.1088/1361-6382/ae2416","DOIUrl":"https://doi.org/10.1088/1361-6382/ae2416","url":null,"abstract":"In this paper, we propose a relationship between the so-called Hubble–Lemaî tre constant H0 and the holographic complexity related to the emergence of spacetime in quantum gravity. Such a result can represent an important step to understanding the Hubble tension by introducing a quantum gravity perspective for cosmological observations, regarding the degree of quantum complexity we measure around us.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"34 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145711410","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 : 2025-12-10DOI: 10.1088/1361-6382/ae255d
Dilip Kumar
In this study, we explore the combined effects of quantum gravity induced by non-commutativity and scale-dependent gravitational coupling on the thermal properties of the thin accretion disks around a Schwarzschild black hole. We consider a κ-deformed renormalization group induced (RGI) Schwarzschild black hole, where the classical Schwarzschild black hole geometry is modified by the κ-deformation of space-time and the running Newton’s coupling constant G(r). Using the modified metric, we derive the geodesic motion of massive particles, the effective potential, and the thermal properties such as the radiated energy flux, luminosity, and the temperature profile of the accretion disk around the κ-deformed RGI-Schwarzschild black hole. Our study shows that when non-commutativity is combined with the RGI framework, the effects produce a noticeable deviation from the classical Schwarzschild case. In particular, for small values of the deformation parameter, we observe an increase in the peak energy flux and the temperature of the accretion disk. This suggests that quantum gravity corrections enhance the disk’s radiative efficiency, especially in the inner regions closer to the black hole.
{"title":"Effect of noncommutative geometry on accretion disks around RGI-Schwarzschild black hole","authors":"Dilip Kumar","doi":"10.1088/1361-6382/ae255d","DOIUrl":"https://doi.org/10.1088/1361-6382/ae255d","url":null,"abstract":"In this study, we explore the combined effects of quantum gravity induced by non-commutativity and scale-dependent gravitational coupling on the thermal properties of the thin accretion disks around a Schwarzschild black hole. We consider a κ-deformed renormalization group induced (RGI) Schwarzschild black hole, where the classical Schwarzschild black hole geometry is modified by the κ-deformation of space-time and the running Newton’s coupling constant G(r). Using the modified metric, we derive the geodesic motion of massive particles, the effective potential, and the thermal properties such as the radiated energy flux, luminosity, and the temperature profile of the accretion disk around the κ-deformed RGI-Schwarzschild black hole. Our study shows that when non-commutativity is combined with the RGI framework, the effects produce a noticeable deviation from the classical Schwarzschild case. In particular, for small values of the deformation parameter, we observe an increase in the peak energy flux and the temperature of the accretion disk. This suggests that quantum gravity corrections enhance the disk’s radiative efficiency, especially in the inner regions closer to the black hole.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"20 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145711414","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 : 2025-12-08DOI: 10.1088/1361-6382/ae2414
Shuanglin Huang, Xuefeng Feng and Yun-Kau Lau
Motivated by a geometric understanding of the angular velocity of a Kerr black hole in terms of a quasi-conformal map that describes a 2d Beltrami fluid flow, a new way to construct initial data sets for binary rotating black holes by prescribing the angular velocities of the two black holes at their horizons is discussed. A set of elliptic equations with prescribed Dirichlet boundary conditions at the horizons and at spatial infinity is established for constructing the initial data. To explore the dynamics encoded in these initial data, we consider the conformally flat three-metric case and numerically evolve it using the BSSN code for two co-rotating and counter-rotating black holes with angular velocities prescribed at the horizons. When the angular velocities are non-uniform and deviate from a constant value at the horizons, new gravitational waveforms are generated which display certain oscillatory pattern reminiscent of that of quasi-normal ringing in the inspiral phase before merger takes place.
{"title":"Angular velocity of rotating black holes—a new way to construct initial data for binary black holes","authors":"Shuanglin Huang, Xuefeng Feng and Yun-Kau Lau","doi":"10.1088/1361-6382/ae2414","DOIUrl":"https://doi.org/10.1088/1361-6382/ae2414","url":null,"abstract":"Motivated by a geometric understanding of the angular velocity of a Kerr black hole in terms of a quasi-conformal map that describes a 2d Beltrami fluid flow, a new way to construct initial data sets for binary rotating black holes by prescribing the angular velocities of the two black holes at their horizons is discussed. A set of elliptic equations with prescribed Dirichlet boundary conditions at the horizons and at spatial infinity is established for constructing the initial data. To explore the dynamics encoded in these initial data, we consider the conformally flat three-metric case and numerically evolve it using the BSSN code for two co-rotating and counter-rotating black holes with angular velocities prescribed at the horizons. When the angular velocities are non-uniform and deviate from a constant value at the horizons, new gravitational waveforms are generated which display certain oscillatory pattern reminiscent of that of quasi-normal ringing in the inspiral phase before merger takes place.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"138 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145697364","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 : 2025-12-08DOI: 10.1088/1361-6382/ae237a
Harold White, Jerry Vera, Andre Sylvester and Leonard Dudzinski
We present a new class of warp bubble geometries that are both interior-flat and segmented into Gaussian cylinders (interchangeably called ‘nacelles’1throughout the paper), providing an alternative to the continuous toroidal energy distribution of the Alcubierre model. Using the ADM 3+1 formalism, we derive the extrinsic curvature, York time, momentum densities, and energy density for both the Alcubierre baseline and the Gaussian cylinder generalizations with cylinders equally spaced azimuthally around the warp bubble. The interior-flat condition guarantees that observers within the bubble remain synchronized with external clocks, yielding a habitable region of flat spacetime. Unlike the diffuse azimuthal ring of negative energy in the Alcubierre solution, our construction localizes exotic stress-energy into discrete cylindrical channels aligned with the bubble wall. Energy density maps, boost magnitude contours, and three-dimensional isosurfaces demonstrate how these segmented Gaussian cylinders maintain a synchronized interior while tuning curvature effects to end-caps. The results suggest that warp bubbles can be engineered with structurally discrete geometries resembling science-fiction starship architectures, where exotic matter localization, end-cap shaping, and interior flatness are tunable engineering parameters consistent with general relativity. These findings extend the ongoing search for physically motivated warp constructs and underscore the value of bridging theoretical warp metrics with engineering-oriented design principles.
{"title":"Interior-flat cylindrical nacelle warp bubbles: derivation and comparison with Alcubierre model","authors":"Harold White, Jerry Vera, Andre Sylvester and Leonard Dudzinski","doi":"10.1088/1361-6382/ae237a","DOIUrl":"https://doi.org/10.1088/1361-6382/ae237a","url":null,"abstract":"We present a new class of warp bubble geometries that are both interior-flat and segmented into Gaussian cylinders (interchangeably called ‘nacelles’1throughout the paper), providing an alternative to the continuous toroidal energy distribution of the Alcubierre model. Using the ADM 3+1 formalism, we derive the extrinsic curvature, York time, momentum densities, and energy density for both the Alcubierre baseline and the Gaussian cylinder generalizations with cylinders equally spaced azimuthally around the warp bubble. The interior-flat condition guarantees that observers within the bubble remain synchronized with external clocks, yielding a habitable region of flat spacetime. Unlike the diffuse azimuthal ring of negative energy in the Alcubierre solution, our construction localizes exotic stress-energy into discrete cylindrical channels aligned with the bubble wall. Energy density maps, boost magnitude contours, and three-dimensional isosurfaces demonstrate how these segmented Gaussian cylinders maintain a synchronized interior while tuning curvature effects to end-caps. The results suggest that warp bubbles can be engineered with structurally discrete geometries resembling science-fiction starship architectures, where exotic matter localization, end-cap shaping, and interior flatness are tunable engineering parameters consistent with general relativity. These findings extend the ongoing search for physically motivated warp constructs and underscore the value of bridging theoretical warp metrics with engineering-oriented design principles.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"4 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145697348","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 : 2025-12-08DOI: 10.1088/1361-6382/ae1ac7
Colm Talbot, Sylvia Biscoveanu, Aaron Zimmerman, Tomasz Baka, Will M Farr, Jacob Golomb, Charlie Hoy, Andrew Lundgren, Jacopo Tissino, John Veitch, Aditya Vijaykumar and Michael J Williams
Smooth window functions are often applied to strain data when inferring the parameters describing the astrophysical sources of gravitational-wave transients. Within the LIGO-Virgo-KAGRA collaboration, it is conventional to include a term to account for power loss due to this window in the likelihood function. We show that the inclusion of this factor leads to biased inference. The simplest solution to this, omitting the factor, leads to unbiased posteriors and Bayes factor estimates provided the window does not suppress the signal for signal-to-noise ratios (SNRs) , but unreliable estimates of the absolute likelihood. Instead, we propose a multi-stage method that yields consistent estimates for the absolute likelihood in addition to unbiased posterior distributions and Bayes factors for SNRs . Additionally, we demonstrate that the commonly held wisdom that using rectangular windows necessarily leads to biased inference is incorrect.
{"title":"Inference with finite time series: II. The window strikes back","authors":"Colm Talbot, Sylvia Biscoveanu, Aaron Zimmerman, Tomasz Baka, Will M Farr, Jacob Golomb, Charlie Hoy, Andrew Lundgren, Jacopo Tissino, John Veitch, Aditya Vijaykumar and Michael J Williams","doi":"10.1088/1361-6382/ae1ac7","DOIUrl":"https://doi.org/10.1088/1361-6382/ae1ac7","url":null,"abstract":"Smooth window functions are often applied to strain data when inferring the parameters describing the astrophysical sources of gravitational-wave transients. Within the LIGO-Virgo-KAGRA collaboration, it is conventional to include a term to account for power loss due to this window in the likelihood function. We show that the inclusion of this factor leads to biased inference. The simplest solution to this, omitting the factor, leads to unbiased posteriors and Bayes factor estimates provided the window does not suppress the signal for signal-to-noise ratios (SNRs) , but unreliable estimates of the absolute likelihood. Instead, we propose a multi-stage method that yields consistent estimates for the absolute likelihood in addition to unbiased posterior distributions and Bayes factors for SNRs . Additionally, we demonstrate that the commonly held wisdom that using rectangular windows necessarily leads to biased inference is incorrect.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"3 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145697362","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 : 2025-12-05DOI: 10.1088/1361-6382/ae2228
Damianos Iosifidis
We extend the usual vacuum Metric-Affine f(R) gravity by supplementing it with all parity even quadratic invariants in torsion and non-metricity. As we show explicitly this supplementation drastically changes the status of the theory which now propagates an additional scalar degree of freedom on top of the graviton. This scalar degree of freedom has a geometric origin as it relates to spacetime torsion and non-metricity. The resulting theory can be written equivalently as a metric and torsionless scalar–tensor theory whose potential and kinetic term coupling depend on the choice of the function f(R) and the dimensionless parameters of the quadratic invariants respectively.
{"title":"Extended Metric-Affine f(R) gravity with dynamical connection in vacuum","authors":"Damianos Iosifidis","doi":"10.1088/1361-6382/ae2228","DOIUrl":"https://doi.org/10.1088/1361-6382/ae2228","url":null,"abstract":"We extend the usual vacuum Metric-Affine f(R) gravity by supplementing it with all parity even quadratic invariants in torsion and non-metricity. As we show explicitly this supplementation drastically changes the status of the theory which now propagates an additional scalar degree of freedom on top of the graviton. This scalar degree of freedom has a geometric origin as it relates to spacetime torsion and non-metricity. The resulting theory can be written equivalently as a metric and torsionless scalar–tensor theory whose potential and kinetic term coupling depend on the choice of the function f(R) and the dimensionless parameters of the quadratic invariants respectively.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"33 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145673595","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 : 2025-12-05DOI: 10.1088/1361-6382/ae1e55
Zhen-Xiao Zhang, Chen Lan and Yan-Gang Miao
We investigate the quasinormal modes (QNMs) of static and spherically symmetric black holes (BHs) in vacuum within the framework of gravity, and compare them with those in gravity. Based on the symmetric teleparallel equivalent of general relativity, we notice that the gravitational effects arise from non-metricity (the covariant derivative of metrics) in gravity rather than curvature in f(R) or torsion in . Using the finite difference method and the sixth-order Wentzel-Kramers-Brillouin (WKB) method, we compute the QNMs of massless scalar field and electromagnetic field perturbations. Tables of quasinormal frequencies for various parameter configurations are provided based on the sixth-order WKB method. Our findings reveal the differences in the QNMs of BHs in gravity compared to those in f(R) and gravity. This variation demonstrates the impact of different parameter values, offering insights into the characteristics of gravity. These results provide the theoretical groundwork for assessing alternative gravities’ viability through gravitational wave data, and aid probably in picking out the alternative gravity theory that best aligns with the empirical reality.
{"title":"Comparison of quasinormal modes of black holes in f ( T ...","authors":"Zhen-Xiao Zhang, Chen Lan and Yan-Gang Miao","doi":"10.1088/1361-6382/ae1e55","DOIUrl":"https://doi.org/10.1088/1361-6382/ae1e55","url":null,"abstract":"We investigate the quasinormal modes (QNMs) of static and spherically symmetric black holes (BHs) in vacuum within the framework of gravity, and compare them with those in gravity. Based on the symmetric teleparallel equivalent of general relativity, we notice that the gravitational effects arise from non-metricity (the covariant derivative of metrics) in gravity rather than curvature in f(R) or torsion in . Using the finite difference method and the sixth-order Wentzel-Kramers-Brillouin (WKB) method, we compute the QNMs of massless scalar field and electromagnetic field perturbations. Tables of quasinormal frequencies for various parameter configurations are provided based on the sixth-order WKB method. Our findings reveal the differences in the QNMs of BHs in gravity compared to those in f(R) and gravity. This variation demonstrates the impact of different parameter values, offering insights into the characteristics of gravity. These results provide the theoretical groundwork for assessing alternative gravities’ viability through gravitational wave data, and aid probably in picking out the alternative gravity theory that best aligns with the empirical reality.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"124 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145673594","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 : 2025-12-05DOI: 10.1088/1361-6382/ae2376
Misao Sasaki, Vicharit Yingcharoenrat and Ying-li Zhang
In the absence of gravity, Coleman’s theorem states that the O(4)-symmetric instanton solution, which is regular at the origin and exponentially decays at infinity, gives the lowest action. Perturbatively, this implies that any small deformation from O(4)-symmetry gives a larger action. In this letter we investigate the possibility of extending this theorem to the situation where the O(4)-symmetric instanton is singular, provided that the action is finite. In particular, we show a general form of the potential around the origin, which realizes a singular instanton with finite action. We then discuss a concrete example in which this situation is realized, and analyze non-trivial anisotropic deformations around the solution perturbatively. Intriguingly, in contrast to the case of Coleman’s instantons, we find that there exists a deformed solution that has the same action as the one for the O(4)-symmetric solution up to the second order in perturbation. Our result implies that there exist non-O(4)-symmetric solutions with finite action beyond Coleman’s instantons, and gives rise to the possibility of the existence of a non-O(4)-symmetric instanton with a lower action.
{"title":"Beyond Coleman’s instantons","authors":"Misao Sasaki, Vicharit Yingcharoenrat and Ying-li Zhang","doi":"10.1088/1361-6382/ae2376","DOIUrl":"https://doi.org/10.1088/1361-6382/ae2376","url":null,"abstract":"In the absence of gravity, Coleman’s theorem states that the O(4)-symmetric instanton solution, which is regular at the origin and exponentially decays at infinity, gives the lowest action. Perturbatively, this implies that any small deformation from O(4)-symmetry gives a larger action. In this letter we investigate the possibility of extending this theorem to the situation where the O(4)-symmetric instanton is singular, provided that the action is finite. In particular, we show a general form of the potential around the origin, which realizes a singular instanton with finite action. We then discuss a concrete example in which this situation is realized, and analyze non-trivial anisotropic deformations around the solution perturbatively. Intriguingly, in contrast to the case of Coleman’s instantons, we find that there exists a deformed solution that has the same action as the one for the O(4)-symmetric solution up to the second order in perturbation. Our result implies that there exist non-O(4)-symmetric solutions with finite action beyond Coleman’s instantons, and gives rise to the possibility of the existence of a non-O(4)-symmetric instanton with a lower action.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"6 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145673599","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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