Found 5 result(s)
Regular Seminar Gregory Korchemsky (IPhT Saclay)
at: 14:00 room G.O. Jones 208 and Zoom  abstract: It has recently been recognized that various observables in different fourdimensional supersymmetric gauge theories can be computed for an arbitrary 't Hooft coupling as determinants of certain semiinfinite matrices. It turns out that these quantities can be expressed as Fredholm determinants of the socalled Bessel kernel and they are closely related to celebrated TracyWidom distribution (more precisely, its finite temperature generalization) describing levelspacing distributions in matrix models. We exploit this relation to determine their dependence on the â€™t Hooft coupling constant. Unlike the weak coupling expansion, which has a finite radius of convergence, the strong coupling expansion is factorially divergent, necessitating the inclusion of nonperturbative, exponentially small corrections. We develop a method to systematically compute these corrections and discuss the resurgent properties of the resulting transseries. 
Regular Seminar Gregory Korchemsky (IPhT Saclay)
at: 14:45 room Zoom, instructions in abstract  abstract: I will review a recent progress in computing fourpoint correlation functions of infinitely heavy halfBPS operators in planar N = 4 SYM. Taking advantage of integrability of the theory, these correlation functions can be constructed in terms of fundamental building blocks  the octagon form factors. We show that the octagon form factor can be expressed as a Fredholm determinant of an integrable Bessel operator and demonstrate that this representation is very efficient in finding its dependence on the â€™t Hooft coupling and two cross ratios. At weak coupling, this yields a known series representation of the octagon in terms of ladder integrals. At strong coupling, we apply strong Szego limit theorem to develop a systematic expansion of the octagon in the inverse powers of the coupling constant and calculate accompanying expansion coefficients analytically.  Part of the London Integrability Journal Club. Please register at integrabilitylondon.weebly.com if you are a new participant. The link will be emailed on Tuesday. 
Regular Seminar Gregory Korchemsky (IPhT Saclay)
at: 14:00 room zoom  abstract: [For zoom link please contact s.nagyATqmul.ac.uk. There will be a preseminar for students at 13:30] The energyenergy correlation (EEC) measures the angular distribution of the energy that flows through two calorimeters separated by some relative angle in the final state created by a source. We present a new approach to computing this observable that exploits the relation between the energy correlations and fourpoint correlation functions of conserved currents. In the limit of small and large angles, when EEC describes the correlation between particles belonging, respectively, to the same jet and to two almost backtoback jets, we obtain a concise representation of the EEC in terms of the conformal data of twisttwo operators and verify it by comparing with the results of explicit calculation at nexttonexttoleading order in maximally supersymmetric YangMills theory. As a byproduct of our analysis, we predict the maximal weight part of the analogous QCD expression. 
Regular Seminar Gregory Korchemsky (Saclay)
at: 14:00 room 602  abstract: I will review a recent progress in computing scattering amplitudes in N=4 SYM theory and explain the recently found duality between MHV gluon scattering amplitudes and correlation functions of halfBPS protected operators in the limit where the positions of the adjacent operators become lightlike separated. 
Regular Seminar Gregory Korchemsky (Universite ParisSud)
at: 14:00 room 503 Huxley  abstract:
