Light rings and shadows of static black holes in effective quantum gravity II: A new solution without Cauchy horizons
Among the three known types of static solutions proposed within the Hamiltonian constraint approach to effective quantum gravity (EQG), the first two have been extensively investigated, whereas the third type-which preserves general covariance, is free of Cauchy horizons, and was only recently obtai...
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Elsevier
2025-09-01
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| Series: | Physics Letters B |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S0370269325005039 |
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| author | Wentao Liu Di Wu Jieci Wang |
| author_facet | Wentao Liu Di Wu Jieci Wang |
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| collection | DOAJ |
| description | Among the three known types of static solutions proposed within the Hamiltonian constraint approach to effective quantum gravity (EQG), the first two have been extensively investigated, whereas the third type-which preserves general covariance, is free of Cauchy horizons, and was only recently obtained-remains relatively unexplored. This solution can describe a black hole with an event horizon for certain parameter ranges, or a horizonless compact object beyond those ranges. In this paper, we focus on the third type and show that its light rings feature both stable and unstable branches, and that the black hole shadow size grows with the quantum parameter-unlike in the first two types. However, when we account for both the shadow and the lensing ring, the overall behavior closely resembles that of the second type, in which an increasing quantum parameter leads to a larger portion of the lensing ring being occupied by the shadow. This feature can serve as a hallmark of black holes in EQG, offering a potential way to distinguish them from their GR counterparts. Remarkably, the parameter ranges under which the solution remains a black hole are highly consistent with the current observational constraints on black hole shadows, lending strong support to the classification of the third type of compact object in EQG as a black hole endowed with an event horizon. |
| format | Article |
| id | doaj-art-97ca0fca3caf4b0e9e8ab496ef1100a2 |
| institution | Kabale University |
| issn | 0370-2693 |
| language | English |
| publishDate | 2025-09-01 |
| publisher | Elsevier |
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| series | Physics Letters B |
| spelling | doaj-art-97ca0fca3caf4b0e9e8ab496ef1100a22025-08-20T03:51:49ZengElsevierPhysics Letters B0370-26932025-09-0186813974210.1016/j.physletb.2025.139742Light rings and shadows of static black holes in effective quantum gravity II: A new solution without Cauchy horizonsWentao Liu0Di Wu1Jieci Wang2Department of Physics, Key Laboratory of Low Dimensional Quantum Structures and Quantum Control of Ministry of Education, and Synergetic Innovation Center for Quantum Effects and Applications, Hunan Normal University, Changsha, Hunan 410081, People's Republic of ChinaSchool of Physics and Astronomy, China West Normal University, Nanchong, Sichuan 637002, People's Republic of China; Corresponding authors.Department of Physics, Key Laboratory of Low Dimensional Quantum Structures and Quantum Control of Ministry of Education, and Synergetic Innovation Center for Quantum Effects and Applications, Hunan Normal University, Changsha, Hunan 410081, People's Republic of China; Corresponding authors.Among the three known types of static solutions proposed within the Hamiltonian constraint approach to effective quantum gravity (EQG), the first two have been extensively investigated, whereas the third type-which preserves general covariance, is free of Cauchy horizons, and was only recently obtained-remains relatively unexplored. This solution can describe a black hole with an event horizon for certain parameter ranges, or a horizonless compact object beyond those ranges. In this paper, we focus on the third type and show that its light rings feature both stable and unstable branches, and that the black hole shadow size grows with the quantum parameter-unlike in the first two types. However, when we account for both the shadow and the lensing ring, the overall behavior closely resembles that of the second type, in which an increasing quantum parameter leads to a larger portion of the lensing ring being occupied by the shadow. This feature can serve as a hallmark of black holes in EQG, offering a potential way to distinguish them from their GR counterparts. Remarkably, the parameter ranges under which the solution remains a black hole are highly consistent with the current observational constraints on black hole shadows, lending strong support to the classification of the third type of compact object in EQG as a black hole endowed with an event horizon.http://www.sciencedirect.com/science/article/pii/S0370269325005039 |
| spellingShingle | Wentao Liu Di Wu Jieci Wang Light rings and shadows of static black holes in effective quantum gravity II: A new solution without Cauchy horizons Physics Letters B |
| title | Light rings and shadows of static black holes in effective quantum gravity II: A new solution without Cauchy horizons |
| title_full | Light rings and shadows of static black holes in effective quantum gravity II: A new solution without Cauchy horizons |
| title_fullStr | Light rings and shadows of static black holes in effective quantum gravity II: A new solution without Cauchy horizons |
| title_full_unstemmed | Light rings and shadows of static black holes in effective quantum gravity II: A new solution without Cauchy horizons |
| title_short | Light rings and shadows of static black holes in effective quantum gravity II: A new solution without Cauchy horizons |
| title_sort | light rings and shadows of static black holes in effective quantum gravity ii a new solution without cauchy horizons |
| url | http://www.sciencedirect.com/science/article/pii/S0370269325005039 |
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