Triangle Seminars
Monday, 9 Jun 2025
Lonti: Superstring Perturbation Theory (4/4)
📍 London
Ashoke Sen
(ICTS, Bangalore)
Abstract:
Please register at https://forms.gle/pHFLVU2XeZu39gzVA
The world-sheet CFT for bosonic string theory, matter and ghost system, BRST charge, physical state condition
Definition of higher genus Riemann surfaces, defining CFT correlations on higher genus Riemann surfaces, bosonic string amplitudes at any loop order
Heterotic and superstring theory, world-sheet CFT of matter and ghosts, picture number and picture changing operator, superstring amplitude at any loop order
Vertical integration and removal of spurious divergences
Please register at https://forms.gle/pHFLVU2XeZu39gzVA
The world-sheet CFT for bosonic string theory, matter and ghost system, BRST charge, physical state condition
Definition of higher genus Riemann surfaces, defining CFT correlations on higher genus Riemann surfaces, bosonic string amplitudes at any loop order
Heterotic and superstring theory, world-sheet CFT of matter and ghosts, picture number and picture changing operator, superstring amplitude at any loop order
Vertical integration and removal of spurious divergences
Posted by: andrea
Wednesday, 11 Jun 2025
Disturbing news about the 2+epsilon expansion
Fabiana Cesare
(IHES)
Abstract:
The O(N) Non-Linear Sigma Model (NLSM) in d=2+epsilon has long been conjectured to describe the same conformal field theory as the Wilson-Fisher O(N) fixed point obtained from the (phi^2)^2 model in
d=4-epsilon. In this talk, we put this conjecture into question, building on the recent observation [Jones,2024] that the NLSM CFT possesses a protected operator with dimension N-1, which is instead absent in the WF O(N) CFT. We propose several scenarios that may explain this discrepancy.
The O(N) Non-Linear Sigma Model (NLSM) in d=2+epsilon has long been conjectured to describe the same conformal field theory as the Wilson-Fisher O(N) fixed point obtained from the (phi^2)^2 model in
d=4-epsilon. In this talk, we put this conjecture into question, building on the recent observation [Jones,2024] that the NLSM CFT possesses a protected operator with dimension N-1, which is instead absent in the WF O(N) CFT. We propose several scenarios that may explain this discrepancy.
Posted by: IC2
Spin Matrix theory and SU(1,n) type of holography in N=4 SYM
📍 London
Yang Lei
(Soochow University)
Abstract:
The Spin Matrix theory is the non-relativistic decoupled limit of N=4 SYM, capturing the near BPS dynamics of N=4 SYM. In this talk I will review the construction of Spin Matrix theory I have been doing in the past few years, following 2012.08532, 2111.10149, 2211.16519. These models could also be viewed as models of holography with SU(1,1) and SU(1,2) type of symmetry. As a nontrivial generalization of Lorentzian type of theories, we will discuss the state-operator correspondence in SU(1,2) type CFT.
The Spin Matrix theory is the non-relativistic decoupled limit of N=4 SYM, capturing the near BPS dynamics of N=4 SYM. In this talk I will review the construction of Spin Matrix theory I have been doing in the past few years, following 2012.08532, 2111.10149, 2211.16519. These models could also be viewed as models of holography with SU(1,1) and SU(1,2) type of symmetry. As a nontrivial generalization of Lorentzian type of theories, we will discuss the state-operator correspondence in SU(1,2) type CFT.
Posted by: QMW
Friday, 13 Jun 2025
Black hole cohomologies at finite N
📍 London
Sunjin Choi
(IPMU)
Abstract:
We study new cohomologies for the local BPS operators of the maximal super-Yang-Mills theory to better understand the black hole microstates. We first analyze the index of these black hole operators, and explicitly construct their cohomologies to study how they imitate the quantum black holes. We find many towers of states and partial no-hair behaviors, where certain gravtions are forbidden to dress these black hole operators. This qualitatively agrees with the behavior of the perturbative hairy BPS black holes or the so-called grey galaxies. Throughout this talk, we mainly focus on a subsector of the field theory corresponding to the BMN matrix theory, which exhibits a black hole-like entropy growth at large N.
We study new cohomologies for the local BPS operators of the maximal super-Yang-Mills theory to better understand the black hole microstates. We first analyze the index of these black hole operators, and explicitly construct their cohomologies to study how they imitate the quantum black holes. We find many towers of states and partial no-hair behaviors, where certain gravtions are forbidden to dress these black hole operators. This qualitatively agrees with the behavior of the perturbative hairy BPS black holes or the so-called grey galaxies. Throughout this talk, we mainly focus on a subsector of the field theory corresponding to the BMN matrix theory, which exhibits a black hole-like entropy growth at large N.
Posted by: QMW