Irish Quantum Foundations      3-4 May 2013

Clare Burrage Dark Energy Screening Mechanisms

I will discuss why we expect dark energy to interact with Standard Model fields, and why this seems to be in conflict with observations. This problem is avoided in dark energy models with screening mechanisms, and I will show how they work and the implications for observations.

Pasquale Calabrese Quantum quenches in one dimensional systems

Non-equilibrium quantum systems represent one of the most promising possibilities for realizing novel states of matter. I will consider the non equilibrium situation known as quantum quench, in which a closed system evolves from an initial state that is not a Hamiltonian eigenstate such as those achieved by suddenly switching a control parameter. An important question is under what conditions the system reaches a stationary state and in which circumstances this state is characterized by an effective "thermal", i.e. equilibrium, distribution. I will discuss how to obtain the time evolution of observables and correlation functions with a variety of theoretical techniques including quantum field theory (in particular CFT) and integrability. These approaches allow to have a rather complete understanding of the relaxation dynamics and the most challenging open problems will be presented.

Eoin Condron Cosmic censorship and the collapse of a scalar field in cylindrical symmetry

We model the collapse of the scalar field in self-similar cylindrical symmetry, with an initial regular axis. Previous work determined full solutions to the field equations up to the past null cone of the scaling origin, which is a regular singular point of the system. We now present partial solutions to the system in the region beyond the past null cone of the origin and discuss the issue of cosmic censorship relative to this model of collapse. Solutions are shown to be analytic in a neighbourhood of this point and are approximated in this neighbourhood using truncated series. In some cases, these approximations lead to global solutions being obtained.

Veselin Filev Magnetic Catalysis in compact spaces

I will describe the properties of a quantum field theory in compact space subjected to an external magnetic field. In the context of the AdS/CFT correspondence this is realized by introducing flavour branes to the AdS5 x S5 geometry in global coordinates. The dual field theory lives on a round three sphere. The theory has a finite Casimir free energy having dissociating effect on the fundamental condensate of the theory. This competes with the pairing effect of the magnetic field leading to an interesting phase structure.

Zoltan Fodor Lattice results with physical quark masses and continuum extrapolation

Lattice QCD reached a new era delivering results with physical quark masses and continuum extrapolation. Selected results will be presented both at vanishing and non-vanishing temperatures.

Thomas Gilroy Genus 2 Recursion of Correlation Functions for Vertex Operator Algebras

I will explain how recursion formulae for the genus 2 correlation functions of a Vertex Operator Algebra (VOA) have been developed using Zhu's recursion formulae for the genus 1 correlation functions of a VOA and a sewing procedure on Riemann surfaces. These genus 2 recursion formulae allow for explicit calculation of genus 2 Ward Identities and Virasoro n-point correlation functions.

Steven Gratton Cosmological Results from Planck

In this talk I will summarize the recent cosmological results from the Planck satellite mission. I will describe how the standard six-parameter cosmological model fits the Planck data very well. Implications for extensions to this model and for various inflationary models for the very early universe will also be discussed.

Layla Hormozi Fractional Quantum Hall of Lattice Bosons Near Commensurate Flux

We study interacting bosons on a lattice in a magnetic field. When the number of flux quanta per plaquette is close to a rational fraction, the low energy physics is mapped to a multi-species continuum model: bosons in the lowest Landau level where each boson is given an internal degree of freedom, or pseudospin. We find that the interaction potential between the bosons involves terms that do not conserve pseudospin, corresponding to umklapp processes, which in some cases can also be seen as BCS-type pairing terms. We argue that in experimentally realistic regimes for bosonic atoms in optical lattices with synthetic magnetic fields, these terms are crucial in determining the nature of allowed ground states. In particular, we show numerically that certain paired wavefunctions related to the Moore-Read Pfaffian state are stabilized by these terms, whereas certain other wavefunctions can be destabilized when umklapp processes become strong. Some of the properties these paired states and their excitation spectra will be also be discussed.

Maria Johnstone The EVH/CFT Correspondence

I will explain how, when a 5d asymptotically AdS (Anti deSitter) black hole has a very small horizon area, the region very close to it is described locally by a 3d BTZ black hole. This in turn has a dual description by the AdS/CFT correspondence in terms of a 2d CFT, the quantum numbers of which can be mapped to those of the 4d CFT that is dual to the original 5d black hole.

Marianne Leitner Modular differential equations in CFT

The characters of the (2,5) minimal model in CFT satisfy an ordinary differential equation which is modular. We discuss the corresponding equations in other minimal models and indicate how to generalise them to higher genus Riemann surfaces.

Benjamin McKay A tour of G2 manifolds

I hope to explain the holonomy group of a metric on a manifold, and the group G2, and how G2 metrics show up in physics. I will survey old and recent results on G2 metrics and their singularities and relations to Calabi Yau metrics. I will then survey some flows that might help to make G2 metrics out of metrics that are not quite G2.

Ronan McNulty The structure of the proton viewed using electroweak and diffractive data at the LHC.

The LHCb experiment at the LHC has a unique kinematic range, being instrumented in the forward region between pseudorapidities of 2 and 5 and able to trigger and reconstruct particles with transverse momenta down to 100 MeV/c. This allows several precise probes of the structure of the proton. W and Z bosons are sensitive to the sea and valence quark distributions at Q**2~10**4 GeV**2 in the x-region above 10**-4. The Drell-Yan production of dimuons below the Z resonance extends the reach down to Q**2~25 GeV**2 and x-values above 10**-5. The central exclusive production of vector mesons is sensitive to the gluon PDF, provides evidence for the hard pomeron, and probes x-values down to 10**-6, a kinematic region never experimentally accessible before, and one where saturation effects may become important.

Donal O'Connell Colour-kinematics duality

The conjectural colour-kinematics duality suggests that there is an algebraic structure governing the kinematic dependence of gauge-theoretic and gravitational amplitudes. I will review the status of the conjecture, and describe newly developed methods for making the duality explicit at one loop.

Nathan Seiberg Supersymmetric Gauge Theories in 3d

We will review known and new facts about the dynamics of 3d N=2 supersymmetric field theories. We will emphasize the role of dualities in these theories and will elucidate their origin.

Dimitri Skliros Duality of Cosmic F-String Decay Rates

Using a toy model, I will discuss how low energy classical physics emerges out of quantum string theory with an explicit example. The example is a radiating quantum string and its classical limit.

Christopher Thomas Hadron spectroscopy from lattice QCD

The spectroscopy and interactions of hadrons provide probes of the strongly-interacting regime of Quantum Chromodynamics (QCD) where we lack a complete understanding of many phenomena. By developing a variety of novel techniques, we have recently made significant progress in using lattice QCD to perform ab-initio calculations of spectra of excited mesons and their transitions. I will discuss some highlights of the results, the challenges in studying unstable states on the lattice and opportunities to understand some puzzling experimental observations.

Michael Tuite Higher Genus Ward Identities

I will review some recent results from the theory of vertex operator algebras on genus two (and higher) Riemann surfaces formed from sewn tori. In particular we discuss explicit Ward identities arising from a genus two version of Zhu recursion theory.