Triangle Seminars
Wednesday, 9 Nov 2016
An algebraic approach to the classification of supergravity backgrounds
📍 London
Jose Miguel Figueroa-O'Farrill
(Edinburgh)
Abstract:
I will report on joint work with Andrea Santi outlining an algebraic reformulation of the classification problem of eleven-dimensional supergravity backgrounds. The basic object of study is the Killing superalgebra of the background, whose algebraic structure has recently been elucidated. If time permits I will also comment on work also involving Paul de Medeiros applying these techniques to the construction of rigidly supersymmetric theories in curved spaces.
I will report on joint work with Andrea Santi outlining an algebraic reformulation of the classification problem of eleven-dimensional supergravity backgrounds. The basic object of study is the Killing superalgebra of the background, whose algebraic structure has recently been elucidated. If time permits I will also comment on work also involving Paul de Medeiros applying these techniques to the construction of rigidly supersymmetric theories in curved spaces.
Posted by: KCL
Integrable deformations of AdS superstrings
Ben Hoare
(Zurich, ETH)
Abstract:
In this talk I will describe recent progress towards understanding integrable deformations of superstrings in AdS backgrounds. One well-known example of such a deformation is the TsT transformation, which involves a T-duality, a shift introducing the deformation parameter, and a reverse T-duality. After introducing this deformation, I will give two alternative constructions: (i) as a particular non-abelian duality, and (ii) as a particular Yang-Baxter deformation. In the second part of the talk I will outline how this extends to a general relationship between non-abelian duality and Yang-Baxter deformations, and discuss the consequences for the Weyl invariance of the deformed models.
In this talk I will describe recent progress towards understanding integrable deformations of superstrings in AdS backgrounds. One well-known example of such a deformation is the TsT transformation, which involves a T-duality, a shift introducing the deformation parameter, and a reverse T-duality. After introducing this deformation, I will give two alternative constructions: (i) as a particular non-abelian duality, and (ii) as a particular Yang-Baxter deformation. In the second part of the talk I will outline how this extends to a general relationship between non-abelian duality and Yang-Baxter deformations, and discuss the consequences for the Weyl invariance of the deformed models.
Posted by: IC
Thursday, 10 Nov 2016
A magnetically induced quantum critical point in holography
Olga Papadoulaki
(Utrecht)
Abstract:
Abstract:
We are using holography to study quantum phase transitions in a 2+1 D strongly coupled non conformal gauge theory at finite chemical potential and magnetic field B. Our gravity dual is 4D N = 2 Fayet-Iliopoulos gauged supergravity. We found a line of quantum critical points at B= Bc between extremal dyonic black branes and extremal magnetically charged "thermal gas" solutions. We will introduce the two types of solutions, their thermodynamics and their phase diagram. Then we will discuss the physics of the critical point and we will point out qualitative similarities between our field theory and Nambu- Jona- Lasinio model in 2+1 D under the presence of an external magnetic field. We will conclude with some open questions both on the gravity and field theory side and we will discuss future directions.
Abstract:
We are using holography to study quantum phase transitions in a 2+1 D strongly coupled non conformal gauge theory at finite chemical potential and magnetic field B. Our gravity dual is 4D N = 2 Fayet-Iliopoulos gauged supergravity. We found a line of quantum critical points at B= Bc between extremal dyonic black branes and extremal magnetically charged "thermal gas" solutions. We will introduce the two types of solutions, their thermodynamics and their phase diagram. Then we will discuss the physics of the critical point and we will point out qualitative similarities between our field theory and Nambu- Jona- Lasinio model in 2+1 D under the presence of an external magnetic field. We will conclude with some open questions both on the gravity and field theory side and we will discuss future directions.
Posted by: IC
Twistors and Conformal Higher-Spin Theory
Tristan McLoughlin
(Trinity College Dublin)
Abstract:
Higher-spin fields can play an important role in effective field theories and increasingly are of interest due to their appearance in recent studies of holography.
Understanding their interactions is however often involved and searching for alternative formulations could be very useful. In this talk we will consider
one such formulation, namely twistors. After giving a general introduction to the use of twistors in describing the dynamics of massless field theories, we will focus on the construction of off-shell actions directly in twistor space including a recent higher-spin generalisation of self-dual Weyl gravity. We will show how this formulation produces the expected flat space-time spectrum and linearised symmetries. In analogy with the known embedding of Einstein gravity inside Weyl gravity, we identify a ghost free sub-sector of the conformal higher-spin theory and consider its cubic couplings. Finally we describe proposed anti-self-dual interaction terms to extend the twistor action to the full conformal higher-spin theory.
Higher-spin fields can play an important role in effective field theories and increasingly are of interest due to their appearance in recent studies of holography.
Understanding their interactions is however often involved and searching for alternative formulations could be very useful. In this talk we will consider
one such formulation, namely twistors. After giving a general introduction to the use of twistors in describing the dynamics of massless field theories, we will focus on the construction of off-shell actions directly in twistor space including a recent higher-spin generalisation of self-dual Weyl gravity. We will show how this formulation produces the expected flat space-time spectrum and linearised symmetries. In analogy with the known embedding of Einstein gravity inside Weyl gravity, we identify a ghost free sub-sector of the conformal higher-spin theory and consider its cubic couplings. Finally we describe proposed anti-self-dual interaction terms to extend the twistor action to the full conformal higher-spin theory.
Posted by: QMW