{"id":526,"date":"2026-05-21T10:06:51","date_gmt":"2026-05-21T08:06:51","guid":{"rendered":"https:\/\/kmpb.physik.hu-berlin.de\/?post_type=tribe_events&p=526"},"modified":"2026-06-15T16:22:00","modified_gmt":"2026-06-15T14:22:00","slug":"qft-colloquia-day-with-john-gracey-and-radu-roiban","status":"publish","type":"tribe_events","link":"https:\/\/kmpb.physik.hu-berlin.de\/index.php\/event\/qft-colloquia-day-with-john-gracey-and-radu-roiban\/","title":{"rendered":"QFT Colloquia Day with John Gracey and Radu Roiban"},"content":{"rendered":"

Announcing the special QFT Colloquia Day on Friday, 19 June, starting at 12:00, at room 1.221 (CSMB building), Zum Gro\u00dfen Windkanal 2, 12489 Berlin.<\/p>\n

12:00 – Prof. John Gracey<\/strong> (University of Liverpool), <\/em>title and abstract below<\/p>\n

13:00 – Joint lunch break with coffee, tea, bagels and wraps<\/strong><\/p>\n

14:30 – Prof. Radu Roiban<\/strong> (PennState – Eberly College of Science), title and abstract below<\/em><\/p>\n

 <\/p>\n

Topics in conformal field theories in d dimensions – <\/strong>Prof. John Gracey (University of Liverpool)<\/em><\/p>\n

We report on recent work in relation to properties of conformal field theories in spacetime dimensions d > 2. The presentation is in two parts where the focus in the first is on scalar cubic theories which are studied in relation to the Lee-Yang model and percolation theory. Estimates of critical exponents at the Wilson-Fisher fixed point derived from Schnetz’s six loop renormalization are produced. Applying resummation methods the exponent estimates are in good agreement with estimates from other methods such as Monte Carlo, high T_c expansions, functional renormalization group and the conformal bootstrap. The second part concentrates on nonabelian gauge theories and in particular the Banks-Zaks-Caswell (BZC) fixed point in four dimensions which defines the conformal window. Using the BZC expansion we compute several critical exponents to fourth order for SU(3) producing estimates which, with a suitable resummation, are in reasonable agreement with lattice field theory across the full conformal window. An estimate of the location of the lower conformal window boundary is indicated and compared with those from other methods. The situation with other colour groups and quark representations is also discussed.<\/div>\n
<\/div>\n
\n
Scattering as a probe of fundamental interactions<\/strong> – Prof. John Gracey (University of Liverpool)<\/em><\/div>\n<\/div>\n
\n
<\/div>\n
Scattering amplitudes reveal a hidden simplicity in particle interactions that is often obscured by individual Feynman diagrams.<\/div>\n
I will explain how modern methods use locality, analyticity, unitarity, and symmetry to reconstruct amplitudes from their singularity structure, making explicit the cancellations and simplifications that occur. Gravity provides particularly striking applications: amplitudes expose surprising relations between gauge theory and gravity, known as the double copy, provide new ways to extract classical observables relevant to compact-object dynamics, and probe the high-energy structure of quantum gravity and supergravity. Along the way, these problems have driven the development of computational tools that play an important role in precision predictions across quantum field theory. The focus will be on the conceptual picture rather than technical details.<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"

Announcing the special QFT Colloquia Day on Friday, 19 June, starting at 12:00, at room 1.221 (CSMB building), Zum Gro\u00dfen Windkanal 2, 12489 Berlin. 12:00 – Prof. John Gracey (University […]<\/p>\n","protected":false},"author":6,"featured_media":0,"comment_status":"open","ping_status":"closed","template":"","meta":{"_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,"_EventAllDay":false,"_EventTimezone":"UTC+2","_EventStartDate":"2026-06-19 12:00:00","_EventEndDate":"2026-06-19 16:00:00","_EventStartDateUTC":"2026-06-19 09:00:00","_EventEndDateUTC":"2026-06-19 13:00:00","_EventShowMap":true,"_EventShowMapLink":true,"_EventURL":"","_EventCost":"","_EventCostDescription":"","_EventCurrencySymbol":"","_EventCurrencyCode":"","_EventCurrencyPosition":"","_EventDateTimeSeparator":"","_EventTimeRangeSeparator":"","_EventOrganizerID":[],"_EventVenueID":[],"_OrganizerEmail":"","_OrganizerPhone":"","_OrganizerWebsite":"","_VenueAddress":"","_VenueCity":"","_VenueCountry":"","_VenueProvince":"","_VenueState":"","_VenueZip":"","_VenuePhone":"","_VenueURL":"","_VenueStateProvince":"","_VenueLat":"","_VenueLng":"","_VenueShowMap":false,"_VenueShowMapLink":false,"_tribe_events_status":"","_tribe_events_status_reason":"","footnotes":"","_tec_slr_enabled":"","_tec_slr_layout":""},"tags":[],"tribe_events_cat":[],"class_list":["post-526","tribe_events","type-tribe_events","status-publish","hentry"],"ticketed":false,"_links":{"self":[{"href":"https:\/\/kmpb.physik.hu-berlin.de\/index.php\/wp-json\/wp\/v2\/tribe_events\/526","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/kmpb.physik.hu-berlin.de\/index.php\/wp-json\/wp\/v2\/tribe_events"}],"about":[{"href":"https:\/\/kmpb.physik.hu-berlin.de\/index.php\/wp-json\/wp\/v2\/types\/tribe_events"}],"author":[{"embeddable":true,"href":"https:\/\/kmpb.physik.hu-berlin.de\/index.php\/wp-json\/wp\/v2\/users\/6"}],"replies":[{"embeddable":true,"href":"https:\/\/kmpb.physik.hu-berlin.de\/index.php\/wp-json\/wp\/v2\/comments?post=526"}],"version-history":[{"count":3,"href":"https:\/\/kmpb.physik.hu-berlin.de\/index.php\/wp-json\/wp\/v2\/tribe_events\/526\/revisions"}],"predecessor-version":[{"id":537,"href":"https:\/\/kmpb.physik.hu-berlin.de\/index.php\/wp-json\/wp\/v2\/tribe_events\/526\/revisions\/537"}],"wp:attachment":[{"href":"https:\/\/kmpb.physik.hu-berlin.de\/index.php\/wp-json\/wp\/v2\/media?parent=526"}],"wp:term":[{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kmpb.physik.hu-berlin.de\/index.php\/wp-json\/wp\/v2\/tags?post=526"},{"taxonomy":"tribe_events_cat","embeddable":true,"href":"https:\/\/kmpb.physik.hu-berlin.de\/index.php\/wp-json\/wp\/v2\/tribe_events_cat?post=526"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}