Triangle Seminars
July 2011
Thu
14 Jul 2011
Doubled geometry
Jeon Imtak
(Sogang Univ.)
Mon
11 Jul 2011
From Navier-Stokes to Einstein
Andrew Strominger
(Harvard)
Abstract:
.
.
Posted by: QMW
Thu
7 Jul 2011
The Kerr/CFT correspondence
Wei Song
(Harvard)
Abstract:
The Kerr/CFT correspondence is the conjectured holographic duality between Kerr black holes and a two dimensional conformal field theory. The original conjecture applies for four dimensional extremal Kerr, but later there are various generalizations in many directions.
In this talk, I will first review how Kerr/CFT works for extremal, near-extremal and non-extremal Kerr black holes. Then I will describe some recent developments on the microscopic understanding of Kerr/CFT by studying some five dimensional examples.
The Kerr/CFT correspondence is the conjectured holographic duality between Kerr black holes and a two dimensional conformal field theory. The original conjecture applies for four dimensional extremal Kerr, but later there are various generalizations in many directions.
In this talk, I will first review how Kerr/CFT works for extremal, near-extremal and non-extremal Kerr black holes. Then I will describe some recent developments on the microscopic understanding of Kerr/CFT by studying some five dimensional examples.
Posted by: QMW
May 2011
Thu
26 May 2011
Towards Big Divisor Swiss Cheese mu-Split Supersymmetry Scenario
Aalok Misra
(IIT, Roorkee)
Abstract:
Starting with type IIB string theory compactified on an orientifold of a Swiss-Cheese Calabi-Yau expressed as a degree-18 hypersurface in the weighted complex projective space WCP4(1,1,1,6,9), in the presence of a mobile space-time filling D3-brane and fluxed (stack(s) of) space-time filling D7-brane(s) wrapping the 'big' (as opposed to the 'small') divisor, we give a geometric proposal for obtaining a super-massive gravitino in the inflationary epoch and a 'light' gravitino in the present era in a single setup. We also show that the setup naturally realizes a 'mu-split supersymmetry scenario' wherein having restricted the mobile D3-brane to the big divisor, one obtains super-massive D3-brane positon moduli - identified as the two Higgs doublets - at the string scale and after 1-loop Nath-Arnowitt RG-evolution to the EW scale, one obtains one light and one super-massive Higgs doublet. Also, the fermions (quarks-leptons) corresponding to the fermionic super-partners of the Wilson line moduli, are very light but the Higgsino mass parameter is very large. I also discuss issues like neutrino masses, gluino and proton decays. As a bonus, I will discuss obtaining the geometric Kaehler potential (relevant to the moduli space Kaehler potential in the presence of a mobile D3-brane) corresponding to a Ricci-flat metric for the Swiss-Cheese Calabi-Yau used in the large volume limit using Gauged Linear Sigma Model techniques for obtaining the geometric Kaehler potential for the big divisor, and the Donaldson's algorithm for obtaining Ricci-flat metrics, as guides.
Starting with type IIB string theory compactified on an orientifold of a Swiss-Cheese Calabi-Yau expressed as a degree-18 hypersurface in the weighted complex projective space WCP4(1,1,1,6,9), in the presence of a mobile space-time filling D3-brane and fluxed (stack(s) of) space-time filling D7-brane(s) wrapping the 'big' (as opposed to the 'small') divisor, we give a geometric proposal for obtaining a super-massive gravitino in the inflationary epoch and a 'light' gravitino in the present era in a single setup. We also show that the setup naturally realizes a 'mu-split supersymmetry scenario' wherein having restricted the mobile D3-brane to the big divisor, one obtains super-massive D3-brane positon moduli - identified as the two Higgs doublets - at the string scale and after 1-loop Nath-Arnowitt RG-evolution to the EW scale, one obtains one light and one super-massive Higgs doublet. Also, the fermions (quarks-leptons) corresponding to the fermionic super-partners of the Wilson line moduli, are very light but the Higgsino mass parameter is very large. I also discuss issues like neutrino masses, gluino and proton decays. As a bonus, I will discuss obtaining the geometric Kaehler potential (relevant to the moduli space Kaehler potential in the presence of a mobile D3-brane) corresponding to a Ricci-flat metric for the Swiss-Cheese Calabi-Yau used in the large volume limit using Gauged Linear Sigma Model techniques for obtaining the geometric Kaehler potential for the big divisor, and the Donaldson's algorithm for obtaining Ricci-flat metrics, as guides.
Posted by: QMW
Thu
19 May 2011
Three-Point Functions and Integrability in AdS/CFT: Weak/strong coupling match
Nikolay Gromov
(KCL)
Abstract:
We compute three-point functions of single trace operators in planar N = 4 SYM. We consider the limit where one of the operators is much smaller than the other two. We find a precise match between weak and strong coupling in the Frolov-Tseytlin classical limit for a very general class of classical solutions. To achieve this match we clarify the issue of back-reaction and identify precisely which three-point functions are captured by a classical computation.
We compute three-point functions of single trace operators in planar N = 4 SYM. We consider the limit where one of the operators is much smaller than the other two. We find a precise match between weak and strong coupling in the Frolov-Tseytlin classical limit for a very general class of classical solutions. To achieve this match we clarify the issue of back-reaction and identify precisely which three-point functions are captured by a classical computation.
Posted by: QMW
Thu
12 May 2011
Dualities for scattering amplitudes in planar N=4 SYM
Paul Heslop
(Durham)
Abstract:
I will review weak-weak dualities relating scattering amplitudes to Wilson loops on the one hand and correlation functions of gauge invariant operators on the other. The Wilson loop / amplitude duality has lead to both numerical and analytic results for MHV scattering amplitudes at two-loops and beyond, including the determination of two loop MHV n-point scattering amplitudes for any n in a certain kinematical regime. The duality with correlation functions has been extended to all scattering amplitudes in the theory and we give explicit examples illustrating this.
I will review weak-weak dualities relating scattering amplitudes to Wilson loops on the one hand and correlation functions of gauge invariant operators on the other. The Wilson loop / amplitude duality has lead to both numerical and analytic results for MHV scattering amplitudes at two-loops and beyond, including the determination of two loop MHV n-point scattering amplitudes for any n in a certain kinematical regime. The duality with correlation functions has been extended to all scattering amplitudes in the theory and we give explicit examples illustrating this.
Posted by: QMW
Wed
11 May 2011
Seiberg-Witten Theory and the Bethe ansatz
📍 London
Nick Dorey
(DAMTP)
Thu
5 May 2011
The first year of the LHC: results and prospects
Michelangelo Mangano
(CERN)
Abstract:
A review of the first lessons that are emerging from the data collected so far, as seen from the point of view of a phenomenologist interested in the validation of the available theoretical tools, as preparation for the challenge of major discoveries.
A review of the first lessons that are emerging from the data collected so far, as seen from the point of view of a phenomenologist interested in the validation of the available theoretical tools, as preparation for the challenge of major discoveries.
Posted by: QMW
April 2011
Thu
7 Apr 2011
Quantum geometry of refined topological strings
Daniel Krefl
(UC - Berkeley)
Abstract:
I will explain how refined topological string partition functions in the Nekrasov-Shatashvilli limit naturally follow from probing the underlying quantum geometry.
I will explain how refined topological string partition functions in the Nekrasov-Shatashvilli limit naturally follow from probing the underlying quantum geometry.
Posted by: QMW
March 2011
Thu
31 Mar 2011
Holography and Superconductors
Julian Sonner
(IC)
Abstract:
Holographic superconductors are gravitational backgrounds, in the sense of gauge-gravity duality, that produce the symmetry breaking pattern and associated phenomenology of superconductors in the boundary theory dual to the gravity solution. In this talk I will describe how such systems are constructed, how they can be embedded into M-theory (and string theory) and how their hydrodynamic description at strong coupling can be derived from the gravity picture.
Holographic superconductors are gravitational backgrounds, in the sense of gauge-gravity duality, that produce the symmetry breaking pattern and associated phenomenology of superconductors in the boundary theory dual to the gravity solution. In this talk I will describe how such systems are constructed, how they can be embedded into M-theory (and string theory) and how their hydrodynamic description at strong coupling can be derived from the gravity picture.
Posted by: QMW
Wed
30 Mar 2011
Three-point functions in AdS/CFT and functional light-cone methods
📍 London
Tristan McLoughlin
(AEI)
Abstract:
In this talk we will briefly review the recent progress in the semiclassical string theory calculation of non-BPS gauge theory three-point correlation functions at strong coupling. We will then discuss the light-cone path integral approach to such three-point functions with a focus on near-BMN operators where one can systematically go beyond the semiclassical approximation.
In this talk we will briefly review the recent progress in the semiclassical string theory calculation of non-BPS gauge theory three-point correlation functions at strong coupling. We will then discuss the light-cone path integral approach to such three-point functions with a focus on near-BMN operators where one can systematically go beyond the semiclassical approximation.
Posted by: KCL
Wed
23 Mar 2011
Deriving the hydrodynamical description of holographic superfluids
📍 London
Julian Sonner
(Imperial and Cambridge)
Abstract:
In my talk I will describe a class of gravitational solutions which, in the context of AdS/CFT, are dual to boundary field theories with spontaneous symmetry breaking and thus give rise to a superfluid phase. I will give a general introduction to the ideas of quantum criticality and how AdS/CFT techniques may be applied to such systems. I will then use the tools of gauge/gravity duality to demonstrate that the boundary description of such systems, in the hydrodynamical limit, is governed by a relativistic generalisation of the Tisza-Landau two-fluid model.
In my talk I will describe a class of gravitational solutions which, in the context of AdS/CFT, are dual to boundary field theories with spontaneous symmetry breaking and thus give rise to a superfluid phase. I will give a general introduction to the ideas of quantum criticality and how AdS/CFT techniques may be applied to such systems. I will then use the tools of gauge/gravity duality to demonstrate that the boundary description of such systems, in the hydrodynamical limit, is governed by a relativistic generalisation of the Tisza-Landau two-fluid model.
Posted by: KCL
Wed
23 Mar 2011
New Physics at the LHC
📍 London
See link See link
Abstract:
http://www.kcl.ac.uk/nms/depts/physics/news/TheNewPhysics AT theLHC.aspx
http://www.kcl.ac.uk/nms/depts/physics/news/TheNewPhysics AT theLHC.aspx
Posted by: KCL
Wed
23 Mar 2011
Special lecture by Prof. John McKay
John McKay
Wed
16 Mar 2011
Physical properties of p-wave holographic superconductors
Johanna Erdmenger
(Munich)
Abstract:
Recently, considerable progress has been achieved in using gauge/gravity
duality for describing strongly coupled systems of relevance for condensed
matter physics. In this context, I discuss both top-down approaches and
bottom-up approaches to holographic superconductors where the order
parameter has p-wave symmetry. In the top-down approach considered, the
holographic superconductors are realized in a probe brane construction
involving a probe of two D-branes at finite isospin density. The dual
field theory is known explicitly. We obtain the thermodynamics, the
transport properties and the Fermi surface for these systems. Moreover, we
consider bottom-up approaches for p-wave superconductors in which we study
the back-reaction of the required SU(2) gauge field on the geometry. We
find the phase diagram. A particularly interesting feature of this model
is that the shear viscosity over entropy ratio displays non-universal
behaviour, it is temperature-dependent at leading order in N and lambda
Recently, considerable progress has been achieved in using gauge/gravity
duality for describing strongly coupled systems of relevance for condensed
matter physics. In this context, I discuss both top-down approaches and
bottom-up approaches to holographic superconductors where the order
parameter has p-wave symmetry. In the top-down approach considered, the
holographic superconductors are realized in a probe brane construction
involving a probe of two D-branes at finite isospin density. The dual
field theory is known explicitly. We obtain the thermodynamics, the
transport properties and the Fermi surface for these systems. Moreover, we
consider bottom-up approaches for p-wave superconductors in which we study
the back-reaction of the required SU(2) gauge field on the geometry. We
find the phase diagram. A particularly interesting feature of this model
is that the shear viscosity over entropy ratio displays non-universal
behaviour, it is temperature-dependent at leading order in N and lambda
Posted by: IC
Wed
16 Mar 2011
Holographic superconductors from gauged supergravity
Jorge Russo
(Barcelona)
Abstract:
Gauged supergravities arise from consistent truncations of string theory and provide a solid framework for condensed matter applications, in a context where the dual field theory is well understood. In this talk we shall discuss different models, including p-wave superconductivity by condensation of a two-form potential.
Gauged supergravities arise from consistent truncations of string theory and provide a solid framework for condensed matter applications, in a context where the dual field theory is well understood. In this talk we shall discuss different models, including p-wave superconductivity by condensation of a two-form potential.
Posted by: QMW
Tue
15 Mar 2011
Mirror Symmetry for Grassmannians
Konstanze Rietsch
(Kings)
Thu
10 Mar 2011
Alternative approaches to Quantum Gravity
Fay Dowker Fotini Markopoulou and John Barret
Abstract:
There will be three introductory 45 minute talks on non string theory approaches to quantum gravity.
There will be three introductory 45 minute talks on non string theory approaches to quantum gravity.
Posted by: QMW
Wed
9 Mar 2011
TBA
Mukund Rangamani
(Durham)
Tue
8 Mar 2011
Stability and wall-crossing
Tom Bridgeland
(Oxford)
Abstract:
In algebraic geometry and string theory there has been a lot of recent work on so-called wall-crossing phenomena for Donaldson-Thomas invariants.
In this talk we will study a baby example of wall-crossing, which already has some non-trivial consequences. I will not assume any previous knowledge of algebraic geometry, just some basic properties of the category of modules over a ring.
In algebraic geometry and string theory there has been a lot of recent work on so-called wall-crossing phenomena for Donaldson-Thomas invariants.
In this talk we will study a baby example of wall-crossing, which already has some non-trivial consequences. I will not assume any previous knowledge of algebraic geometry, just some basic properties of the category of modules over a ring.
Posted by: KCL
Thu
3 Mar 2011
Yangian symmetry in N=4 super Yang-Mills
Livia Ferro
(Berlin)
Abstract:
Scattering amplitudes in N=4 super Yang-Mills theory have been extensively studied in recent years, due to their remarkable features. In particular, planar amplitudes exhibit a hidden symmetry, the dual superconformal symmetry. I will review how, together with the standard superconformal one, it forms a Yangian structure. Then I will discuss some recent results about the Yangian symmetry of light-like Wilson loops at one loop.
Scattering amplitudes in N=4 super Yang-Mills theory have been extensively studied in recent years, due to their remarkable features. In particular, planar amplitudes exhibit a hidden symmetry, the dual superconformal symmetry. I will review how, together with the standard superconformal one, it forms a Yangian structure. Then I will discuss some recent results about the Yangian symmetry of light-like Wilson loops at one loop.
Posted by: QMW
Wed
2 Mar 2011
Fusion of line operators, and quantum integrability in AdS/CFT
📍 London
Raphael Benichou
(VUB)
Abstract:
I will present recent progress in the understanding of two-dimensional sigma-models on the supergroup PSl(nIn). I will emphasize the relevance of these models to study quantum integrability in the AdS/CFT correspondence. In particular i will explain the computation of the fusion of some line operators, the transfer matrices, that encode an infinite number of conserved charges. This computation leads to a first-principle, perturbative derivation of the Hirota equation, which has been argued to provide a solution to the spectrum problem in N=4 SYM.
I will present recent progress in the understanding of two-dimensional sigma-models on the supergroup PSl(nIn). I will emphasize the relevance of these models to study quantum integrability in the AdS/CFT correspondence. In particular i will explain the computation of the fusion of some line operators, the transfer matrices, that encode an infinite number of conserved charges. This computation leads to a first-principle, perturbative derivation of the Hirota equation, which has been argued to provide a solution to the spectrum problem in N=4 SYM.
Posted by: KCL
February 2011
Thu
24 Feb 2011
tba
Malcolm Fairbairn
(King's)
Wed
23 Feb 2011
An OPE for Polygonal null Wilson Loops
📍 London
Luis Fernando Alday
(Oxford)
Wed
23 Feb 2011
Some Generalized Geometry and M theory
Malcolm Perry
(Cambridge)
Wed
16 Feb 2011
M5's, D4's and 5D SYM
Costis Papageorgakis
(King's)
Abstract:
We revisit the relationship between the 6D (2, 0) M5 CFT compactified on a circle to 5D maximally supersymmetric YM Gauge Theory. We show that in the broken phase 5D SYM contains a spectrum of soliton states that can be identified with the complete KK modes of an M2 ending on the M5's. This
provides evidence that the (2,0) theory on a circle is equivalent to 5D SYM with no additional UV degrees of freedom, suggesting that the latter is in fact a well-defined quantum theory and possibly finite.
We revisit the relationship between the 6D (2, 0) M5 CFT compactified on a circle to 5D maximally supersymmetric YM Gauge Theory. We show that in the broken phase 5D SYM contains a spectrum of soliton states that can be identified with the complete KK modes of an M2 ending on the M5's. This
provides evidence that the (2,0) theory on a circle is equivalent to 5D SYM with no additional UV degrees of freedom, suggesting that the latter is in fact a well-defined quantum theory and possibly finite.
Posted by: QMW
Wed
16 Feb 2011
U(1) symmetries in F-theory compactifications
Timo Weigand
(Heidelberg)
Tue
15 Feb 2011
Reinforcement Learning in Evolutionary Games
Robert Seymour
(UCL)
Thu
10 Feb 2011
(de)Tails of Toda CFT
Nadav Drukker
(IC)
Wed
9 Feb 2011
M5's, D4's and 5D SYM
📍 London
Costis Papageorgakis
(King's)
Abstract:
We revisit the relation of the six-dimensional (2, 0) M5-brane Conformal Field Theory compactified on a circle to 5D maximally supersymmetric Yang-Mills Gauge Theory. We show that in the broken phase 5D super-Yang-Mills contains a spectrum of soliton states that can be identified with the complete Kaluza-Klein modes of an M2-brane ending on the M5-branes. This provides evidence that the (2,0) theory on a circle is equivalent to 5D super-Yang-Mills with no additional UV degrees of freedom, suggesting that the latter is in fact a well-defined quantum theory and possibly finite.
We revisit the relation of the six-dimensional (2, 0) M5-brane Conformal Field Theory compactified on a circle to 5D maximally supersymmetric Yang-Mills Gauge Theory. We show that in the broken phase 5D super-Yang-Mills contains a spectrum of soliton states that can be identified with the complete Kaluza-Klein modes of an M2-brane ending on the M5-branes. This provides evidence that the (2,0) theory on a circle is equivalent to 5D super-Yang-Mills with no additional UV degrees of freedom, suggesting that the latter is in fact a well-defined quantum theory and possibly finite.
Posted by: KCL
Wed
9 Feb 2011
From Water Waves to Solitons and String Theory
Timothy Hollowood
(Swansea)
Thu
3 Feb 2011
Light-front holographic QCD and the bound-state structure of hadrons
Guy F. de Teramond
(Universidad de Costa Ric)
Wed
2 Feb 2011
A Wilsonian perspective on the Holographic Renormalization Group
📍 London
Mukund Rangamani
(Durham)
Wed
2 Feb 2011
Dimer models and children's drawings
Vishnu Jejjala
(Queen Mary)
January 2011
Wed
26 Jan 2011
M-theory and Generalised geometry
📍 London
David Berman
(Queen Mary)
Abstract:
We reformulate M-theory in a duality manifest way using generalised
geometry.
We reformulate M-theory in a duality manifest way using generalised
geometry.
Posted by: KCL
Wed
26 Jan 2011
Regge Cuts and Excited State TBA
Volker Schomerus
(DESY)
Tue
25 Jan 2011
Three Kinds of Vortex Integrability
Nick Manton
(DAMTP, Cambridge)
Abstract:
The equations for Abelian Higgs vortices (magnetic flux vortices) on a plane
or a more general surface are generally not integrable, but for vortices
on a hyperbolic plane of curvature -1/2 they are. This talk will
present (almost explicit) vortex solutions on certain compact hyperbolic
surfaces. Also to be discussed are two asymptotically solvable problems
for vortices: the effective vortex motion on a large surface with
small curvature, and the structure of vortex solutions on a small
surface where the vortices are about to dissolve (and the equations
linearize).
These results (obtained with N. Rink and with N. Romao) bring vortex
theory closer to classical results on the complex and metric geometry
of Riemann surfaces.
The equations for Abelian Higgs vortices (magnetic flux vortices) on a plane
or a more general surface are generally not integrable, but for vortices
on a hyperbolic plane of curvature -1/2 they are. This talk will
present (almost explicit) vortex solutions on certain compact hyperbolic
surfaces. Also to be discussed are two asymptotically solvable problems
for vortices: the effective vortex motion on a large surface with
small curvature, and the structure of vortex solutions on a small
surface where the vortices are about to dissolve (and the equations
linearize).
These results (obtained with N. Rink and with N. Romao) bring vortex
theory closer to classical results on the complex and metric geometry
of Riemann surfaces.
Posted by: KCL
Thu
20 Jan 2011
Constructing Self-Dual Strings
Christian Saemann
(Edinburgh)
Abstract:
I will present an ADHMN-like construction which generates self-dual string solutions to the effective M5-brane worldvolume theory from solutions to the Basu-Harvey equation.
I will present an ADHMN-like construction which generates self-dual string solutions to the effective M5-brane worldvolume theory from solutions to the Basu-Harvey equation.
Posted by: QMW
Wed
19 Jan 2011
Higher n-point functions in AdS_3/CFT_2
📍 London
Ingo Kirsch
(DESY)
Wed
19 Jan 2011
Periods of CY Manifolds in Physics and Number Theory
📍 London
Philip Candelas
(Oxford)
Wed
12 Jan 2011
TBA
📍 London
Carlos Tamarit
(KITP)