Triangle Seminars
Monday, 10 Jun 2019
Conformal block, Crossing Kernel and Multi-variable Hypergeometric Functions
Heng-Yu Chen
(National Taiwan University)
Abstract:
In this talk, based on the work to appear, we present an alternative representation of the conformal block with external scalars in general spacetime dimensions in terms of a finite summation over Appell fourth hypergeometric function, and its generalization to the primary operator exchange with continuous spin which is relevant for Lorentzian spacetime. Using these results we apply the Lorentzian inversion formula to compute so-called crossing kernel in general spacetime dimensions, and the result can be written as a double infinite summation over certain Kempe de Feriet hypergeometric functions. During the talk, we will introduce various physical quantities and discuss their subtitles and applications.
In this talk, based on the work to appear, we present an alternative representation of the conformal block with external scalars in general spacetime dimensions in terms of a finite summation over Appell fourth hypergeometric function, and its generalization to the primary operator exchange with continuous spin which is relevant for Lorentzian spacetime. Using these results we apply the Lorentzian inversion formula to compute so-called crossing kernel in general spacetime dimensions, and the result can be written as a double infinite summation over certain Kempe de Feriet hypergeometric functions. During the talk, we will introduce various physical quantities and discuss their subtitles and applications.
Posted by: oxford
Wednesday, 12 Jun 2019
Euclidean Wormholes and Holography
Panos Betzios
(Crete)
Abstract:
In this talk I will discuss asymptotically AdS wormhole solutions in the
context of holography.
I will present how to compute correlation functions of local operators
as well as non local observables such as correlation functions of Wilson
loops on the distinct boundaries and I will discuss their behavior.
Moreover, I will discuss the effect that multi-trace deformations have
on such observables.
From the computations mentioned we observe that the dual theory is
expected to be described in terms of two interacting sectors coupled by
a
UV soft, non-local interaction.
Finally, I will present a simple effective field theory construction
that can
explain the behaviors that we observe from these gravitational
computations.
In this talk I will discuss asymptotically AdS wormhole solutions in the
context of holography.
I will present how to compute correlation functions of local operators
as well as non local observables such as correlation functions of Wilson
loops on the distinct boundaries and I will discuss their behavior.
Moreover, I will discuss the effect that multi-trace deformations have
on such observables.
From the computations mentioned we observe that the dual theory is
expected to be described in terms of two interacting sectors coupled by
a
UV soft, non-local interaction.
Finally, I will present a simple effective field theory construction
that can
explain the behaviors that we observe from these gravitational
computations.
Posted by: IC
Eikonal phase shift in AdS black holes vs multi-stress-tensor OPEs in holographic CFT
Gim Seng Ng
(Trinity College Dublin)
Abstract:
We study the leading and next-to-leading eikonal phase in the context of AdS/CFT. In the bulk side, we compute the phase shift of a highly energetic particle traveling in the background of an asymptotically AdS black hole. In the dual CFT, the phase shift is related to a four point function in the Regge limit. The black hole mass is translated to the ratio between the conformal dimension of a heavy operator and the central charge. This ratio serves as a useful
expansion parameter; its power measures the number of stress tensors appearing in the intermediate channel.
The leading eikonal phase shift in 4d holographic CFTs can be computed using conformal Regge theory while the computation of the next-to-leading order eikonal phase shift relies on a new universal formula for the lowest-twist OPE of double-trace stress-tensors with two scalar operators. These OPE coefficients are consistent with the second-order phase shift as well as anomalous dimensions obtained in AdS black holes in the lightcone limit. In relations to the
idea of “eikonalization†of the stress-tensor sector in holographic CFTs, we comment on hints of a structure similar to the vacuum Virasoro block in 2d CFT.
We study the leading and next-to-leading eikonal phase in the context of AdS/CFT. In the bulk side, we compute the phase shift of a highly energetic particle traveling in the background of an asymptotically AdS black hole. In the dual CFT, the phase shift is related to a four point function in the Regge limit. The black hole mass is translated to the ratio between the conformal dimension of a heavy operator and the central charge. This ratio serves as a useful
expansion parameter; its power measures the number of stress tensors appearing in the intermediate channel.
The leading eikonal phase shift in 4d holographic CFTs can be computed using conformal Regge theory while the computation of the next-to-leading order eikonal phase shift relies on a new universal formula for the lowest-twist OPE of double-trace stress-tensors with two scalar operators. These OPE coefficients are consistent with the second-order phase shift as well as anomalous dimensions obtained in AdS black holes in the lightcone limit. In relations to the
idea of “eikonalization†of the stress-tensor sector in holographic CFTs, we comment on hints of a structure similar to the vacuum Virasoro block in 2d CFT.
Posted by: QMW
Thursday, 13 Jun 2019
Heterotic and Bosonic String Amplitudes from Scattering Equations
Fei Teng
(Uppsala University)
Abstract:
In this talk, I will connect, via tree-level double copy, any massless string amplitudes with QFT amplitudes given by Cachazo-He-Yuan (CHY) formula. This can be derived by a detailed study of integration-by-part (IBP) reduction of string integrands. As an application, we consider general multitrace integrands of heterotic string amplitudes. The new technology generates a recursive expansion of the heterotic string amplitudes in terms of those with fewer gravitons and traces, where the kinematic coefficients are building blocks for BCJ numerators of the (DF)^2+YM+phi^3 theory. Finally, we give a generic CHY integrand for multitrace (DF)^2+YM+phi^3 amplitudes, which reproduce the corresponding heterotic string amplitudes after double copy with a single-valued Z-theory.
In this talk, I will connect, via tree-level double copy, any massless string amplitudes with QFT amplitudes given by Cachazo-He-Yuan (CHY) formula. This can be derived by a detailed study of integration-by-part (IBP) reduction of string integrands. As an application, we consider general multitrace integrands of heterotic string amplitudes. The new technology generates a recursive expansion of the heterotic string amplitudes in terms of those with fewer gravitons and traces, where the kinematic coefficients are building blocks for BCJ numerators of the (DF)^2+YM+phi^3 theory. Finally, we give a generic CHY integrand for multitrace (DF)^2+YM+phi^3 amplitudes, which reproduce the corresponding heterotic string amplitudes after double copy with a single-valued Z-theory.
Posted by: QMW