Workshop Navigation
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| Wednesday 27th |
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Thursday 28th |
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Friday 29th |
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| 09:00 |
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09:00-09:25 |
Massimo D'Elia |
09:00-09:50 |
Claes Uggla |
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09:30-09:55 |
Ted Hurley |
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| 10:00 |
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10:00-10:50 |
Ruth Britto |
10:00-10:25 |
Yuhma Asano |
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10:30-10:55 |
Andrei Parnachev |
| 11:00 |
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11:00-11:20 |
Tea & Coffee/ Photo? |
11:00-11:20 |
Tea & Coffee |
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11:20-12:10 |
Costis Papageorgakis |
11:20-12:10 |
Paul Fendley |
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12:20-13:10 |
Matthias Gaberdiel |
12:20-12:45 |
Leron Borsten |
| 13:10 |
Welcome Tea & Coffee |
13:20 |
Lunch break |
13:00 |
Farewell & Reception |
| 14:10-15:00 |
Elli Pomoni |
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14:30-14:45 |
Tamer Boz |
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14:50-15:05 |
Aoife Kelly |
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| 15:10-16:00 |
Samson Abramsky |
15:10-16:00 |
Jørgen E. Andersen |
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| 16:10-16:30 |
Tea & Coffee |
16:10-16:30 |
Tea & Coffee |
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| 16:30-17:20 |
Miguel Paulos |
16:30-16:55 |
Jan Manschot |
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17:00-17:25 |
Brian Dolan |
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| 17:30 |
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17:30-17:55 |
Andreas Ruschhaupt |
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| 18:00 |
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| 19:30 |
O'Raifeartaigh Talk |
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| 20:00 |
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20:00 |
Bar & Conference Dinner* |
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*The Conference Dinner takes place in the Sussex Restaurant at 8:30pm (€40 pp all inclusive). We will meet in the Bar below the restaurant from 8:00pm.
Samson Abramsky: The Mathematics of Contextuality
Contextuality is one of the key non-classical features of quantum physics.
It has been argued recently that it is the key ingredient in quantum computation enabling it to transcend the bounds imposed by classical computation.
We shall explore the rich mathematical structure of contextuality, which includes non-locality as a special case.
The study of non-locality and contextuality can be expressed in a unified and generalised form in the language of sheaves or bundles, in terms of obstructions to global sections. These obstructions can, in many cases, be witnessed by cohomology invariants. There are also strong connections with logic. For example, Bell inequalities, one of the major tools of quantum information and foundations, arise systematically from logical consistency conditions.
These general mathematical characterisations of non-locality and contextuality also allow precise connections to be made with a number of seemingly unrelated topics, in classical computation and logic.
Jørgen Ellegaard Andersen: Quantum Chern-Simons theory via geometric quantisation of moduli spaces
We shall in this talk first review basics about quantum Chern-Simons theory. Following this we will review how one can build this theory both for compact and for non-compact groups using the geometric quantization of the corresponding moduli spaces. We shall end the talk with a discussion of some results and open questions regarding the resulting Topological Quantum Field Theories.
Yuhma Asano: Emergent Geometries from the BMN Matrix Model
Matrix models are considered as non-perturbative definitions of string or M-theory. BMN matrix model is one of the definitions, and its gravity dual is known. Although the corresponding IIA SUGRA solutions were constructed, it had not been observed on the gauge theory side. In this talk, I will show how the geometries actually embed in the BMN matrix model. To sketch the dynamics of the emergent geometries, I also present recent results about chaotic behavior in the BMN matrix model.
Leron Borsten: On the symmetries of "Yang-Mills squared"
There is a long and varied history relating gravity to Yang-Mills theory, with a variety of approaches: from gauging spacetime symmetries to the more recent applications of the holographic principle. Here, instead, we appeal to the idea of "gravity as the square of Yang-Mills" by tensoring left and right multiplets with arbitrary non-Abelian gauge groups GL and GR. Squaring Yang-Mills theories is a recurring theme in attempts to understand the quantum theory of gravity and appears in several different forms. In the context of scattering amplitudes the Bern-Carrasco-Johansson colour/kinematic duality has led to the remarkable conjecture that all loop (super)gravity amplitudes can be written as the "double copy" of (super) Yang-Mills amplitudes. These advances motivate the question: to what extent can a quantum theory of gravity be understood in terms of Yang-Mills squared? We begin to address this puzzle, starting with the local and global symmetries of (super)gravity and (super) Yang-
Mills theories.
Local: By regarding gravity as the convolution of left and right Yang-Mills theories together with a "spectator" scalar field in the biadjoint representation of GL x GR, we derive in linearized approximation, the gravitational symmetries of general covariance, p-form gauge invariance, local Lorentz invariance, and local supersymmetry from the flat space Yang-Mills symmetries of local gauge invariance and global super-Poincaré symmetry.
Global: We give a unified description of D = 3 super-Yang-Mills theory with N = 1, 2, 4, and 8 supersymmeties in terms of the four division algebras: reals (R), complexes (C), quaternions (H) and octonions (O). Tensoring left and right super-Yang-Mills multiplets with N = 1, 2, 4, 8 we obtain a Freudenthal magic square RR, CR, CC, HR, HC, HH, OR, OC, OH, OO description of D = 3 supergravity with N = 2, 3, 4, 5, 6, 8, 9, 10, 12, 16.
Tamer Boz: Two-Color QCD at High Density
QCD at high chemical potential has interesting properties such as deconfinement of quarks. Two-color QCD, which enables numerical simulations on the lattice, constitutes a laboratory to study QCD at high chemical potential. The quark propagator in two-color QCD at high density is referred to as the Gorkov propagator. We examine the Gorkov propagator and in particular, find the form factors of the Gorkov propagator making use of the symmetries it obeys.
Ruth Britto: Feynman integrals with Cuts and Hopf algebra
While Feynman integrals are often very difficult to compute directly, they have recently been found to show some deep algebraic structure.
Discontinuities of Feynman integrals mark one approach to their computation. I will discuss their physical interpretation, in terms of cut diagrams, and ways to embed them in algebraic frameworks which can aid in constructing the full integrals.
Massimo D'Elia: Properties of Strong Interactions in Strong Magnetic Fields
I will review recent results from lattice QCD studies regarding
the properties of strongly interacting matter in the presence
of strong magnetic background fields.
Brian Dolan: Black holes and Boyle's Law -- the role of pressure in black hole thermodynamics
For black holes in asymptotically anti-de Sitter space time the cosmological constant can be viewed as a thermodynamic variable playing the role of pressure and the thermodynamically conjugate variable can then be interpreted as a volume. This point of view leads to van der Waals type critical points and second order phase transitions. Recent work on this new perspective on black hole thermodynamics will be reviewed.
Paul Fendley: What is topological order, and why is it interesting?
Certain condensed-matter systems exhibit seemingly counterintuitive behaviour such as charge fractionalisation, where the emergent degrees of freedom have charge a fraction of the underlying constituents. To characterise and understand such phases precisely, one needs a notion of ordering intermediate between traditional order (e.g. arrows lining up) and disorder (e.g. arrows not lining up). Topological quantities provide such a notion, an moreover illuminate why such behaviour is robust. One spectacular potential application of these ideas is in a topological quantum computer. In this talk I will address these issues by attempting to answer the questions in the title.
Matthias Gaberdiel: Higher Spins & Strings
The conjectured relation between higher spin theories on anti de-Sitter (AdS) spaces
and weakly coupled conformal field theories is reviewed. I shall then outline the
evidence in favour of a concrete duality of this kind, relating a specific higher spin
theory on AdS3 to a family of 2d minimal model CFTs. Finally, I shall explain how
this relation fits into the framework of the familiar stringy AdS/CFT correspondence.
Aoife Kelly: Charm physics at finite temperature
The structure of the quark gluon plasma (QGP) is not yet completely known. Charm mesons provide a probe into the QGP in order to develop a better understanding of this structure. I will discuss the spectral functions of charmonium, and light and strange D mesons obtained from a finite temperature Lattice QCD study.
Jan Manschot: Gauge theory and generalised Appell functions
Partition functions of four-dimensional supersymmetric gauge theories are known to localise on instanton solutions. I'll discuss how these partition functions can be evaluated for gauge group U(N) and when the four-manifold is rational or ruled. The building blocks of these partition functions turn out to be an interesting generalisation of Appell functions.
Costis Papageorgakis: Revisiting soliton contributions to perturbative amplitudes
It is often said that soliton contributions to perturbative processes in QFT are exponentially suppressed by a form-factor. We will provide a derivation of this form-factor by studying the soliton-antisoliton pair-production amplitude. This reduces to the calculation of a matrix element in the quantum mechanics on the soliton moduli space. We will investigate the conditions under which the latter leads to suppression. Extending this framework to instanton-solitons in five-dimensional Yang-Mills theory leaves open the possibility that such contributions will not be suppressed.
Andrei Parnachev: Holographic topological entanglement entropy and ground state degeneracy
Topological entanglement entropy, a measure of the long-ranged entanglement, is related to
the degeneracy of the ground state on a higher genus surface. We construct a class of holographic models where
such relation is similar to the one exhibited by Chern-Simons theory in a certain large
N limit. Both the non-vanishing topological entanglement entropy and the ground state
degeneracy in these holographic models are consequences of the topological Gauss-Bonnet
term in the dual gravitational description.
Miguel Paulos: The super-bootstrap
We study the constraints imposed by superconformal symmetry, crossing symmetry, and unitarity for theories with four supercharges in spacetime dimension $2\leq d\leq 4$. We show how superconformal algebras with four Poincaré supercharges can be treated in a formalism applicable to any, in principle continuous, value of $d$ and use this to construct the superconformal blocks for any $d\leq 4$. We then use numerical bootstrap techniques to derive upper bounds on the conformal dimension of the first unprotected operator appearing in the OPE of a chiral and an anti-chiral superconformal primary.
Elli Pomoni: Integrability and Exact results in N=2 gauge theory
Any N=2 gauge theory in four dimensions contains a set of local
operators made only out of fields in the N=2 vector multiplet that is
closed under renormalization to all loops, namely the SU(2,1|2)
sector. We present a diagrammatic argument that for any planar N=2
theory the SU(2,1|2) Hamiltonian acting on infinite spin chains is
identical to all loops to that of N=4 SYM, up to a redefinition of the
coupling constant g^2 → f(g^2). Thus, this sector is integrable and
anomalous dimensions can be read off from the N=4 ones up to this
redefinition. For each N=2 theory the universal function f(g^2) can be
obtained by computing the circular Wilson loop using Pestun localization and
comparing it to the N = 4 one.
Andreas Ruschhaupt: Shortcuts to Adiabaticity and Optimization of their Stability
Quantum adiabatic processes -that keep constant the populations in the instantaneous eigenbasis of a time-dependent Hamiltonian-are very useful to prepare, manipulate and control quantum states, but take typically a long time. This is often problematic because decoherence and noise may spoil the desired final state.
"Shortcuts to adiabaticity" are alternative fast processes which reproduce the same final populations, or even the same final state, as the adiabatic process in a finite, shorter time. We present such "shortcuts to adiabaticity" for the manipulation of internal atomic states as well as for the manipulation of atomic motional states. We especially study and optimize the stability of different shortcut schemes concerning different types of perturbations like, for example, concerning systematic errors, noise errors and errors originating from unwanted transitions during internal state manipulations and noise error during fast shuttling of trapped ions.
Claes Uggla: Scalar field cosmology
In this talk I will discuss a minimally coupled scalar field and a perfect fluid in flat FRW cosmology from a dynamical systems perspective. I will illustrate various features, such as mechanisms for attractor solutions, global and local dynamical issues, e.g., connections between slow-roll approximations and center manifolds, and averaging techniques, by addressing a number of examples: A modified Chaplygin gas, monomial potentials, inverse power-law potentials, and I will give conditions on the scalar field potential that give rise to models with an attracting saddle separatrix surface, which describes the evolution of an open set of solutions that continuously deform LambdaCDM cosmology. In the latter case I will also provide cosmographic diagrams that complement the dynamical systems pictures and which facilitate comparisons with LambdaCDM cosmology. Finally, I will situate the present models in a larger perspective, indicating how first principles, such as scale-invariance and general covariance, applicable to any kind of source, give rise to hierarchies of models and symmetries were simpler models act as building blocks for understanding more complicated ones.
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