Triangle Seminars
Monday, 7 Dec 2020
Lonti 2020 : D Branes and Boundary States
Bogdan Stefanski
(City)
Abstract:
This is the live session included as part of the LonTI lecture on Conformal blocks in two dimensions. Please register at https://lonti.weebly.com/registration.html to receive joining instructions for this live session which will be held via Zoom. D-branes are a remarkable set of soliton-like objects in string theory which have played a critical role in many areas of string theory. Despite being non-perturbative, they can be understood exactly using world-sheet methods through the boundary state formalism. In this lecture, I introduce the notion of a boundary state and show how to use it to extract physical information about D-branes and the open strings that live on them.
This is the live session included as part of the LonTI lecture on Conformal blocks in two dimensions. Please register at https://lonti.weebly.com/registration.html to receive joining instructions for this live session which will be held via Zoom. D-branes are a remarkable set of soliton-like objects in string theory which have played a critical role in many areas of string theory. Despite being non-perturbative, they can be understood exactly using world-sheet methods through the boundary state formalism. In this lecture, I introduce the notion of a boundary state and show how to use it to extract physical information about D-branes and the open strings that live on them.
Posted by: pethybridge
Tuesday, 8 Dec 2020
Volume preserving diffeomorphism as a higher-rank gauge symmetry
Dam Thanh Son
(Univerity of Chicago)
Abstract:
Recently, theories with higher rank gauge symmetries are drawing attention in condensed matter physics. Such theories are thought to be related to the so-called "fractons," quasiparticles with limited mobility that appear in some lattice models. We show that one version of such higher ranked symmetry can be "nonlinearlized" into volume-preserving diffeomorphism. We demonstrate that several condensed matter systems, including the fractional quantum Hall effect and ferromagnetism, secretly possess this symmetry, which sheds another light to some peculiar features of the quasiparticles in these systems.
[please email a.held@imperial.ac.uk for zoom link or password]
Recently, theories with higher rank gauge symmetries are drawing attention in condensed matter physics. Such theories are thought to be related to the so-called "fractons," quasiparticles with limited mobility that appear in some lattice models. We show that one version of such higher ranked symmetry can be "nonlinearlized" into volume-preserving diffeomorphism. We demonstrate that several condensed matter systems, including the fractional quantum Hall effect and ferromagnetism, secretly possess this symmetry, which sheds another light to some peculiar features of the quasiparticles in these systems.
[please email a.held@imperial.ac.uk for zoom link or password]
Posted by: IC
Wednesday, 9 Dec 2020
An N=1 Lagrangian for an N=3 SCFT
📍 London
Gabi Zafrir
(Milan Bicocca U.)
Abstract:
Purely N=3 SCFTs are naturally strongly coupled, and
expected to not have a Lagrangian description manifesting their N=3
supersymmetry. However, these may be reached through a deformation of
a theory preserving less supersymmetry. We shall present a strategy to
try to conjecture such models, and exemplify it by presenting an N=1
model conjectured to flow to an N=3 SCFT, deformed by a marginal
deformation. We shall also discuss and exemplify how such proposals
can be tested.
[For the Zoom link please email to alejandro.cabo_bizet@kcl.ac.uk]
Purely N=3 SCFTs are naturally strongly coupled, and
expected to not have a Lagrangian description manifesting their N=3
supersymmetry. However, these may be reached through a deformation of
a theory preserving less supersymmetry. We shall present a strategy to
try to conjecture such models, and exemplify it by presenting an N=1
model conjectured to flow to an N=3 SCFT, deformed by a marginal
deformation. We shall also discuss and exemplify how such proposals
can be tested.
[For the Zoom link please email to alejandro.cabo_bizet@kcl.ac.uk]
Posted by: andrea
High energy scattering of highly excited strings
Vladimir Rosenhaus
(IAS)
Abstract:
The n-point tachyon amplitude is a classic and well-known result in bosonic string theory. Rather than studying tachyon amplitudes, we will compute scattering amplitudes involving highly excited string states. Along the way we review and elaborate on the DDF construction of string vertex operators, and describe properties of a generic excited string. Based on work in progress with D. Gross.
The n-point tachyon amplitude is a classic and well-known result in bosonic string theory. Rather than studying tachyon amplitudes, we will compute scattering amplitudes involving highly excited string states. Along the way we review and elaborate on the DDF construction of string vertex operators, and describe properties of a generic excited string. Based on work in progress with D. Gross.
Posted by: IC
Thursday, 10 Dec 2020
An Operator Product Expansion for Form Factors
Matthias Wilhelm
(Niels Bohr Institute Copenhagen)
Abstract:
In this talk, I discuss an operator product expansion for planar form factors of local operators in N=4 SYM theory. In this expansion, a form factor is decomposed into a sequence of known pentagon transitions and a new universal object - the form factor transition. This transition is subject to a set of non-trivial bootstrap constraints, which can be used to determine it at finite coupling. I demonstrate this for MHV form factors of the chiral half of the stress tensor supermultiplet, which in particular contains the chiral Lagrangian and the 20'. –– Part of London Integrability Journal Club. If you are a new participant, please register filling the form at integrability-london.weebly.com. The link will be emailed.
In this talk, I discuss an operator product expansion for planar form factors of local operators in N=4 SYM theory. In this expansion, a form factor is decomposed into a sequence of known pentagon transitions and a new universal object - the form factor transition. This transition is subject to a set of non-trivial bootstrap constraints, which can be used to determine it at finite coupling. I demonstrate this for MHV form factors of the chiral half of the stress tensor supermultiplet, which in particular contains the chiral Lagrangian and the 20'. –– Part of London Integrability Journal Club. If you are a new participant, please register filling the form at integrability-london.weebly.com. The link will be emailed.
Posted by: andrea