{"id":9055,"date":"2025-12-05T14:30:33","date_gmt":"2025-12-05T20:30:33","guid":{"rendered":"https:\/\/uwm.edu\/physics\/?post_type=tribe_events&#038;p=9055"},"modified":"2025-12-05T14:30:33","modified_gmt":"2025-12-05T20:30:33","slug":"cgca-seminar-samuel-e-gralla","status":"publish","type":"tribe_events","link":"https:\/\/uwm.edu\/physics\/event\/cgca-seminar-samuel-e-gralla\/","title":{"rendered":"CGCA Seminar &#8211; Samuel E. Gralla"},"content":{"rendered":"<h2>Can black holes evaporate past extremality?<\/h2>\n<p>Professor Samuel E. Gralla<br \/>\nUniversity of Arizona<\/p>\n<p>Black holes with sufficiently large initial charge and mass will Hawking-evaporate towards the extremal limit. The emission slows as the temperature approaches zero, but still reaches the point where a single Hawking quantum would make the object superextremal, removing the horizon. We take this semiclassical prediction at face value and ask: When the emission occurs, what is revealed?  Using a simple thin-shell model for the matter originally forming the black hole, we find that this matter re-emerges after the horizon is removed and subsequently expands back to large radius.  This expanding remnant has been bathed in the ingoing Hawking quanta during evaporation and presumably carries correlations with the outgoing quanta, offering the attractive possibility of studying information paradox issues in a setup where spacetime curvatures are globally small, so that quantum gravity is not required. Even for ordinary black holes that evaporate down to the Planck size, we propose a radical new scenario for the interior: rather than forming a singularity, the collapsing matter settles onto an outgoing null trajectory inside the horizon for the entirety of evaporation.<\/p>\n","protected":false},"excerpt":{"rendered":"<p><strong>Can black holes evaporate past extremality?<\/strong><br \/>\nProfessor Samuel E. Gralla<br \/>\nUniversity of Arizona<\/p>\n<p>Black holes with sufficiently large initial charge and mass will Hawking-evaporate towards the extremal limit. The emission slows as the temperature approaches zero, but still reaches the point where a single Hawking quantum would make the object superextremal, removing the horizon. We take this semiclassical prediction at face value and ask: When the emission occurs, what is revealed? <\/p>\n","protected":false},"author":9647,"featured_media":0,"template":"","meta":{"_acf_changed":false,"_tribe_events_status":"","_tribe_events_status_reason":"","_tribe_events_is_hybrid":"","_tribe_events_is_virtual":"","_tribe_events_virtual_video_source":"","_tribe_events_virtual_embed_video":"","_tribe_events_virtual_linked_button_text":"","_tribe_events_virtual_linked_button":"","_tribe_events_virtual_show_embed_at":"","_tribe_events_virtual_show_embed_to":[],"_tribe_events_virtual_show_on_event":"","_tribe_events_virtual_show_on_views":"","_tribe_events_virtual_url":"","footnotes":"","uwm_wg_additional_authors":[]},"tags":[],"tribe_events_cat":[46],"class_list":["post-9055","tribe_events","type-tribe_events","status-publish","hentry","tribe_events_cat-cgca-seminars","cat_cgca-seminars"],"yoast_head":"<!-- This site is optimized with the Yoast SEO Premium plugin v27.3 (Yoast SEO v27.3) - https:\/\/yoast.com\/product\/yoast-seo-premium-wordpress\/ -->\n<title>Physics &amp; Astronomy<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/uwm.edu\/physics\/event\/cgca-seminar-samuel-e-gralla\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"CGCA Seminar - Samuel E. 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We take this semiclassical prediction at face value and ask: When the emission occurs, what is revealed?\" \/>\n<meta property=\"og:url\" content=\"https:\/\/uwm.edu\/physics\/event\/cgca-seminar-samuel-e-gralla\/\" \/>\n<meta property=\"og:site_name\" content=\"Physics &amp; Astronomy\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data1\" content=\"1 minute\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\\\/\\\/schema.org\",\"@graph\":[{\"@type\":\"WebPage\",\"@id\":\"https:\\\/\\\/uwm.edu\\\/physics\\\/event\\\/cgca-seminar-samuel-e-gralla\\\/\",\"url\":\"https:\\\/\\\/uwm.edu\\\/physics\\\/event\\\/cgca-seminar-samuel-e-gralla\\\/\",\"name\":\"CGCA Seminar - Samuel E. 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