{"id":7119,"date":"2018-09-13T10:29:21","date_gmt":"2018-09-13T08:29:21","guid":{"rendered":"https:\/\/www.uni.lu\/fr\/events\/physics-colloquium-electromagnetic-edge-modes-as-a-physical-toy-model-for-black-hole-entropy\/"},"modified":"2018-09-13T10:29:21","modified_gmt":"2018-09-13T08:29:21","slug":"physics-colloquium-electromagnetic-edge-modes-as-a-physical-toy-model-for-black-hole-entropy","status":"publish","type":"events","link":"https:\/\/www.uni.lu\/fr\/events\/physics-colloquium-electromagnetic-edge-modes-as-a-physical-toy-model-for-black-hole-entropy\/","title":{"rendered":"Physics Colloquium: Electromagnetic edge modes as a physical toy model for black hole entropy."},"content":{"rendered":"<section class=\"wp-block-unilux-blocks-free-section section\"><div class=\"container xl:max-w-screen-xl\"><p><strong>About the topic<\/strong><\/p><p>In linearised gravity, the Schwarzschild solution and its mass are related to unphysical degrees of freedom rather than physical gravitons. This motivates the study of the analog problem in electromagnetism, where the role of the black hole is played by the Coulomb solution, while mass corresponds to electric charge. When all polarisations of the photon are quantised in an indefinite metric Hilbert space, it is shown (i) that the quantum state corresponding to the classical Coulomb solution is a coherent state of longitudinal and temporal photons, and (ii) that the edge modes of a charged vacuum capacitor give a contribution to the partition function that is proportional to the area and explains the Gibbons-Hawking entropy of the system.<\/p><p><strong>About the speaker<\/strong><\/p><p>Glenn Barnich is a theoretical physicist and professor at the Universit\u00e9 libre de Bruxelles. His research interests center on the structure of gauge and gravitational theories and on ways to quantize them. He regularly teaches a course on Quantum Field Theory in the Physics Master&rsquo;s program in Luxembourg.<\/p><\/div><\/section>","protected":false},"excerpt":{"rendered":"","protected":false},"author":0,"featured_media":7120,"parent":0,"menu_order":0,"comment_status":"open","ping_status":"closed","template":"","format":"standard","meta":{"featured_image_focal_point":[],"show_featured_caption":false,"ulux_newsletter_groups":"","uluxPostTitle":"","uluxPrePostTitle":"","_trash_the_other_posts":false,"_price":"","_stock":"","_tribe_ticket_header":"","_tribe_default_ticket_provider":"","_tribe_ticket_capacity":"0","_ticket_start_date":"","_ticket_end_date":"","_tribe_ticket_show_description":"","_tribe_ticket_show_not_going":false,"_tribe_ticket_use_global_stock":"","_tribe_ticket_global_stock_level":"","_global_stock_mode":"","_global_stock_cap":"","_tribe_rsvp_for_event":"","_tribe_ticket_going_count":"","_tribe_ticket_not_going_count":"","_tribe_tickets_list":"[]","_tribe_ticket_has_attendee_info_fields":false,"event_start_date":"2018-09-19 16:00:00","event_end_date":"2018-09-19 17:30:00","event_speaker_name":"Prof. Glenn Barnich","event_speaker_link":"","event_is_online":false,"event_location":"Campus Limpertsberg - Batiment des Sciences BSC 0.04","event_street":"","event_location_link":"","event_zip_code":"","event_city":"","event_country":"LU"},"events-topic":[316],"events-type":[],"organisation":[76,25,226],"authorship":[],"acf":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO Premium plugin v22.3 (Yoast SEO v22.3) - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>Physics Colloquium: Electromagnetic edge modes as a physical toy model for black hole entropy. - Universit\u00e9 du Luxembourg<\/title>\n<meta name=\"description\" content=\"About the topicIn linearised gravity, the Schwarzschild solution and its mass are related to unphysical degrees of freedom rather than physical gravitons.\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.uni.lu\/fr\/events\/physics-colloquium-electromagnetic-edge-modes-as-a-physical-toy-model-for-black-hole-entropy\/\" \/>\n<meta property=\"og:locale\" content=\"fr_FR\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Physics Colloquium: Electromagnetic edge modes as a physical toy model for black hole entropy.\" \/>\n<meta property=\"og:description\" content=\"About the topicIn linearised gravity, the Schwarzschild solution and its mass are related to unphysical degrees of freedom rather than physical gravitons.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.uni.lu\/fr\/events\/physics-colloquium-electromagnetic-edge-modes-as-a-physical-toy-model-for-black-hole-entropy\/\" \/>\n<meta property=\"og:site_name\" content=\"UNI FR\" \/>\n<meta property=\"article:publisher\" content=\"https:\/\/www.facebook.com\/uni.lu\" \/>\n<meta property=\"og:image\" content=\"https:\/\/www.uni.lu\/wp-content\/uploads\/sites\/11\/2026\/03\/03120045\/UNIV_SM-Profile_1600x1600px-scaled.jpg\" \/>\n\t<meta property=\"og:image:width\" content=\"2560\" \/>\n\t<meta property=\"og:image:height\" content=\"2560\" \/>\n\t<meta property=\"og:image:type\" content=\"image\/jpeg\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Dur\u00e9e de lecture estim\u00e9e\" \/>\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:\/\/www.uni.lu\/fr\/events\/physics-colloquium-electromagnetic-edge-modes-as-a-physical-toy-model-for-black-hole-entropy\/\",\"url\":\"https:\/\/www.uni.lu\/fr\/events\/physics-colloquium-electromagnetic-edge-modes-as-a-physical-toy-model-for-black-hole-entropy\/\",\"name\":\"Physics Colloquium: Electromagnetic edge modes as a physical toy model for black hole entropy. - 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