Quantum cross-section of near-extremal black holes
Abstract We explore how to detect the large quantum fluctuations in the throat of a near-extremal black hole, where the dynamics are governed by the Schwarzian theory. To this end, we scatter a low-frequency wave of a massless, minimal scalar off the black hole and calculate the absorption cross-sec...
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| Language: | English |
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SpringerOpen
2025-04-01
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| Series: | Journal of High Energy Physics |
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| Online Access: | https://doi.org/10.1007/JHEP04(2025)122 |
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| author | Roberto Emparan |
| author_facet | Roberto Emparan |
| author_sort | Roberto Emparan |
| collection | DOAJ |
| description | Abstract We explore how to detect the large quantum fluctuations in the throat of a near-extremal black hole, where the dynamics are governed by the Schwarzian theory. To this end, we scatter a low-frequency wave of a massless, minimal scalar off the black hole and calculate the absorption cross-section. In the semiclassical regime, where the Schwarzian is weakly coupled, we recover the universal result that the cross-section equals the horizon area. However, in the strongly coupled regime, where quantum fluctuations dominate, we find that the absorption cross-section exceeds the semiclassical prediction. This result may seem counterintuitive, given that the density of black hole states is suppressed in this regime. Nevertheless, two effects outweigh this suppression. First, quantum fluctuations enhance absorption transitions between individual states, with the effect becoming stronger closer to the ground state. Second, these fluctuations significantly reduce stimulated emission. We conclude that a measurement showing an enhanced absorption cross-section serves as a clear signature of the large quantum fluctuations in the geometry. |
| format | Article |
| id | doaj-art-b7c18e3ef86d4197a6e218c80810f4d6 |
| institution | OA Journals |
| issn | 1029-8479 |
| language | English |
| publishDate | 2025-04-01 |
| publisher | SpringerOpen |
| record_format | Article |
| series | Journal of High Energy Physics |
| spelling | doaj-art-b7c18e3ef86d4197a6e218c80810f4d62025-08-20T01:49:33ZengSpringerOpenJournal of High Energy Physics1029-84792025-04-012025411610.1007/JHEP04(2025)122Quantum cross-section of near-extremal black holesRoberto Emparan0Institució Catalana de Recerca i Estudis Avançats (ICREA)Abstract We explore how to detect the large quantum fluctuations in the throat of a near-extremal black hole, where the dynamics are governed by the Schwarzian theory. To this end, we scatter a low-frequency wave of a massless, minimal scalar off the black hole and calculate the absorption cross-section. In the semiclassical regime, where the Schwarzian is weakly coupled, we recover the universal result that the cross-section equals the horizon area. However, in the strongly coupled regime, where quantum fluctuations dominate, we find that the absorption cross-section exceeds the semiclassical prediction. This result may seem counterintuitive, given that the density of black hole states is suppressed in this regime. Nevertheless, two effects outweigh this suppression. First, quantum fluctuations enhance absorption transitions between individual states, with the effect becoming stronger closer to the ground state. Second, these fluctuations significantly reduce stimulated emission. We conclude that a measurement showing an enhanced absorption cross-section serves as a clear signature of the large quantum fluctuations in the geometry.https://doi.org/10.1007/JHEP04(2025)122Black HolesBlack Holes in String Theory2D Gravity |
| spellingShingle | Roberto Emparan Quantum cross-section of near-extremal black holes Journal of High Energy Physics Black Holes Black Holes in String Theory 2D Gravity |
| title | Quantum cross-section of near-extremal black holes |
| title_full | Quantum cross-section of near-extremal black holes |
| title_fullStr | Quantum cross-section of near-extremal black holes |
| title_full_unstemmed | Quantum cross-section of near-extremal black holes |
| title_short | Quantum cross-section of near-extremal black holes |
| title_sort | quantum cross section of near extremal black holes |
| topic | Black Holes Black Holes in String Theory 2D Gravity |
| url | https://doi.org/10.1007/JHEP04(2025)122 |
| work_keys_str_mv | AT robertoemparan quantumcrosssectionofnearextremalblackholes |