16:00 zoom A&CKirill Krasnov and Chanon Hasuwannakit (University of Nottingham): Gravity MHV amplitudes from Berends-Giele currents.
Both of the authors of this preprint are planning to speak. We will start by explaining the calculation in the original Berends-Giele 1988 paper, which showed how the Parke-Taylor formula for YM MHV amplitudes can be proven by Feynman diagram calculations, combined with the idea of a recursion relation for these amplitudes. The calculation proceeds in two steps. First, one computes what can be called the all-plus BG current. The derivation is reasonably straightforward, but the current computed does not contribute to any non-vanishing scattering amplitude. Nevertheless, this current exhibits much of the structure of the Parke-Taylor MHV formula. One then proceeds with a much harder calculation of what can be called all-but-one-plus BG current. The combinatorics of this is more non-trivial, but nevertheless an explicit solution is possible. It is from this all-but-one-plus current that the MHV amplitude is eventually extracted.
We then proceed to the computation of exactly the same logic for gravity. To produce Feynman rules of manageable complexity we use the chiral first order formulation of GR. This reasonably quickly leads to the recurrence relations for both the all-plus and all-but-one-plus BG currents. The arising recursion relations are doubles of those in the YM case. The combinatorics of the solution to the all-plus recurrence relation is much more involved than in the YM case, and the solution is a sum over trees. As in the YM case, the all-plus current already exhibits much of the structure of the MHV formula, in its NSVW version. However, to obtain the MHV amplitudes one needs to compute the all-but-one-plus currents. The combinatorics of this is even more non-trivial, but an explicit solution is again possible. We sketch the details of all these computations.
Venue: zoom
13:00 MCS2068 G&TSusovan Pal (Vrije Universiteit Brussel): Manifolds with rough boundaries, and asymptotics of the graph Laplacian
Venue: MCS2068
14:00 MCS2068 ProbAndrew Wade (University of Durham): One-dimensional particle clouds with elastic collisions
Venue: MCS2068
13:00 MCS0001 HEPMSameer Murthy (King's College London): TBA
Venue: MCS0001
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These events are hosted in and/or organised by members of the Department (follow links for details):
Oct 07 [Mary's] Willmore Pure Postgraduate Day
Venue: Mary's at/from 10:00
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Usual Venue: zoom
Contact: arthur.lipstein@durham.ac.uk
Oct 08 16:00 Kirill Krasnov and Chanon Hasuwannakit (University of Nottingham): Gravity MHV amplitudes from Berends-Giele currents.
Both of the authors of this preprint are planning to speak. We will start by explaining the calculation in the original Berends-Giele 1988 paper, which showed how the Parke-Taylor formula for YM MHV amplitudes can be proven by Feynman diagram calculations, combined with the idea of a recursion relation for these amplitudes. The calculation proceeds in two steps. First, one computes what can be called the all-plus BG current. The derivation is reasonably straightforward, but the current computed does not contribute to any non-vanishing scattering amplitude. Nevertheless, this current exhibits much of the structure of the Parke-Taylor MHV formula. One then proceeds with a much harder calculation of what can be called all-but-one-plus BG current. The combinatorics of this is more non-trivial, but nevertheless an explicit solution is possible. It is from this all-but-one-plus current that the MHV amplitude is eventually extracted.
We then proceed to the computation of exactly the same logic for gravity. To produce Feynman rules of manageable complexity we use the chiral first order formulation of GR. This reasonably quickly leads to the recurrence relations for both the all-plus and all-but-one-plus BG currents. The arising recursion relations are doubles of those in the YM case. The combinatorics of the solution to the all-plus recurrence relation is much more involved than in the YM case, and the solution is a sum over trees. As in the YM case, the all-plus current already exhibits much of the structure of the MHV formula, in its NSVW version. However, to obtain the MHV amplitudes one needs to compute the all-but-one-plus currents. The combinatorics of this is even more non-trivial, but an explicit solution is again possible. We sketch the details of all these computations.
Venue: zoom
Usual Venue: MCS2068
Contact: yohance.a.osborne@durham.ac.uk
No upcoming seminars have been scheduled (not unusual outside term time).
Usual Venue: MCS3070
Contact: andrew.krause@durham.ac.uk
No upcoming seminars have been scheduled (not unusual outside term time).
Usual Venue: MCS2068
Contact: herbert.gangl@durham.ac.uk
Oct 14 14:00 Victor Abrashkin (Durham University):
Venue: MCS2068
Oct 21 14:00 Colton Griffin (University of Pennsylvania):
Venue: MCS2068
Nov 04 14:00 Yu-Chen Sun (University of Bristol):
Venue: MCS2068
Nov 11 14:00 Robin Bartlett (University of Glasgow):
Venue: MCS2068
Nov 25 14:00 Dante Luber (Queen Mary University of London): Matroid theory, algebra, and computation
Venue: MCS2068
Dec 02 14:00 Jay Taylor (University of Manchester):
Venue: MCS2068
Dec 09 14:00 Fredrik Stromberg (University of Nottingham):
Venue: MCS2068
Usual Venue: OC218
Contact: mohamed.anber@durham.ac.uk
For more information, see HERE.
No upcoming seminars have been scheduled (not unusual outside term time).
Usual Venue: MCS0001
Contact: inaki.garcia-etxebarria@durham.ac.uk,sunil.chhita@durham.ac.uk
No upcoming seminars have been scheduled (not unusual outside term time).
Usual Venue: MCS0001
Contact: sabine.boegli@durham.ac.uk,alpar.r.meszaros@durham.ac.uk
No upcoming seminars have been scheduled (not unusual outside term time).
Usual Venue: MCS3052
Contact: andrew.krause@durham.ac.uk
No upcoming seminars have been scheduled (not unusual outside term time).
Usual Venue: MCS3070
Contact: daniel.n.disney@durham.ac.uk
No upcoming seminars have been scheduled (not unusual outside term time).
Usual Venue: MCS2068
Contact: fernando.galaz-garcia@durham.ac.uk
Oct 09 13:00 Susovan Pal (Vrije Universiteit Brussel): Manifolds with rough boundaries, and asymptotics of the graph Laplacian
Venue: MCS2068
Oct 16 13:00 Raphael Zentner (Durham University): TBA
Venue: MCS2068
Nov 13 14:00 Jan Rybalko (University of Oslo): TBA
Venue: MCS2068
Nov 20 14:00 Amy Herron (University of Bristol): Triangle Presentations in ~A_2 Bruhat-Tits Buildings
Venue: MCS2068
Jan 22 14:00 Chunyang Hu (Durham University): TBA
Venue: MCS2068
Mar 06 13:00 Julian Scheuer (Goethe University Frankfurt): TBA
Venue: MCS2068
Usual Venue: MCS3070
Contact: mendel.t.nguyen@durham.ac.uk
No upcoming seminars have been scheduled (not unusual outside term time).
Usual Venue: MCS0001
Contact: p.e.dorey@durham.ac.uk,enrico.andriolo@durham.ac.uk,tobias.p.hansen@durham.ac.uk
Oct 10 13:00 Sameer Murthy (King's College London): TBA
Venue: MCS0001
Oct 17 13:00 Neil Lambert (King's College London): TBA
Venue: MCS0001
Oct 24 13:00 Nicola Dondi (ICTP Trieste): TBA
Venue: MCS0001
Oct 31 13:00 Max Hutt (Imperial College London): TBA
Venue: MCS0001
Nov 07 13:00 Stathis Vitouladitis (Université Libre de Bruxelles): TBA
Venue: MCS0001
Nov 14 13:00 Christian Copetti (Oxford): TBA
Venue: MCS0001
Nov 21 13:00 Ida Zadeh (Southampton): TBA
Venue: MCS0001
Nov 28 13:00 Tim Meier (Santiago de Compostela): TBA
Venue: MCS0001
Dec 05 13:00 Marco Meineri (Torino): TBA
Venue: MCS0001
Dec 12 13:00 Sungwoo Hong (KAIST, Taejon): TBA
Venue: MCS0001
Usual Venue: MCS2068
Contact: tyler.helmuth@durham.ac.uk,oliver.kelsey-tough@durham.ac.uk
Oct 09 14:00 Andrew Wade (University of Durham): One-dimensional particle clouds with elastic collisions
Venue: MCS2068
Usual Venue: MCS2068
Contact: michael.r.magee@durham.ac.uk
No upcoming seminars have been scheduled (not unusual outside term time).
Usual Venue: MCS3070
Contact: joe.thomas@durham.ac.uk
No upcoming seminars have been scheduled (not unusual outside term time).
Usual Venue: MCS2068
Contact: hyeyoung.maeng@durham.ac.uk,andrew.iskauskas@durham.ac.uk
Oct 27 13:00 Ben Swallow (St. Andrews):
Venue: MCS2068
Nov 03 13:00 Sam Livingstone (UCL):
Venue: MCS2068
Dec 01 13:00 Markus Rau (Newcastle):
Venue: MCS2068
Contact: adam.stone2@durham.ac.uk
No upcoming seminars have been scheduled (not unusual outside term time).
These link to some of the special events hosted by the Department: