Triangle Seminars
Monday, 2 Jun 2025
Lonti: Superstring Perturbation Theory (3/4)
📍 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
Thursday, 5 Jun 2025
Carroll Approximations of General Relativity, BKL Dynamics and Holography
📍 London
Gerben Oling
(Edinburgh U., Sch. Math.)
Abstract:
What goes on behind the horizon of black holes? A long time ago, general relativity was conjectured to lead to chaotic dynamics in the vicinity of spacelike singularities. Recently, it was observed that this so-called BKL dynamics, which features 'bounces' between Kasner geometries, can be engineered in AdS black holes in a relatively straightforward way using relevant deformations in the dual CFT. However, extracting predictions from Einstein gravity in this near-singularity regime remains extraordinarily challenging, which limits our understanding of the validity and generality of BKL limits as well as their holographic interpretation in AdS/CFT. In this talk, I will present a novel approach to the challenges of near-singularity dynamics and its holographic interpretation using ultra-local geometric Carroll approximations of gravity.
What goes on behind the horizon of black holes? A long time ago, general relativity was conjectured to lead to chaotic dynamics in the vicinity of spacelike singularities. Recently, it was observed that this so-called BKL dynamics, which features 'bounces' between Kasner geometries, can be engineered in AdS black holes in a relatively straightforward way using relevant deformations in the dual CFT. However, extracting predictions from Einstein gravity in this near-singularity regime remains extraordinarily challenging, which limits our understanding of the validity and generality of BKL limits as well as their holographic interpretation in AdS/CFT. In this talk, I will present a novel approach to the challenges of near-singularity dynamics and its holographic interpretation using ultra-local geometric Carroll approximations of gravity.
Posted by: QMW
Classical Gravitational Wave Tails from Soft Theorem
📍 London
Ashoke Sen
(ICTS, Bangalore)
Abstract:
If a set of massive objects collide in space and the fragments disperse, possibly forming black holes, then this process will emit gravitational waves. Computing the detailed gravitational wave-form associated with this process is a complicated problem, not only due to the non-linearity of gravity but also due to the fact that during the collision and subsequent fragmentation the objects could undergo complicated non-gravitational interactions. Nevertheless the classical soft graviton theorem determines the power law fall-off of the wave-form at late and early times, including logarithmic corrections, in terms of only the momenta of the incoming and outgoing objects without any reference to what transpired during the collision. I shall explain the results, briefly outline the derivation of these results and discuss possible generalizations and applications.
The talk will be followed by a reception in Bush House (SE) 2.12. Participation is free, but external attendees are asked to register on https://www.eventbrite.co.uk/e/mathematics-colloquiaclassical-gravitational-wave-tails-from-soft-theorem-tickets-1354870717789?aff=oddtdtcreator.
If a set of massive objects collide in space and the fragments disperse, possibly forming black holes, then this process will emit gravitational waves. Computing the detailed gravitational wave-form associated with this process is a complicated problem, not only due to the non-linearity of gravity but also due to the fact that during the collision and subsequent fragmentation the objects could undergo complicated non-gravitational interactions. Nevertheless the classical soft graviton theorem determines the power law fall-off of the wave-form at late and early times, including logarithmic corrections, in terms of only the momenta of the incoming and outgoing objects without any reference to what transpired during the collision. I shall explain the results, briefly outline the derivation of these results and discuss possible generalizations and applications.
The talk will be followed by a reception in Bush House (SE) 2.12. Participation is free, but external attendees are asked to register on https://www.eventbrite.co.uk/e/mathematics-colloquiaclassical-gravitational-wave-tails-from-soft-theorem-tickets-1354870717789?aff=oddtdtcreator.
Posted by: andrea
Why Nobody Understands Quantum Physics
Frank Verstraete
(Cambridge U)
Abstract:
Prof. Frank Verstraete and Celine Broeckaert invite you to a talk celebrating 100 years of quantum and the launch of their book: Why Nobody Understands Quantum Physics. The talk is at the Royal Institution (21 Albemarle St, London W1S 4BS). Please RSVP at RSVPEVENTS_at_MACMILLAN.COM.
Prof. Frank Verstraete and Celine Broeckaert invite you to a talk celebrating 100 years of quantum and the launch of their book: Why Nobody Understands Quantum Physics. The talk is at the Royal Institution (21 Albemarle St, London W1S 4BS). Please RSVP at RSVPEVENTS_at_MACMILLAN.COM.
Posted by: QMW