# 9th Bologna Workshop on CFT and Integrable Models

15-18 September 2014
Dept. of Physics and Astronomy
Europe/Rome timezone
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Displaying 25 contributions out of 25
Type: Talk Session: Monday afternoon
The scalar products and certain correlation functions of models solvable by the quantum separation of variables can be expressed in terms of $N$-fold multiple integrals which can be thought of as the partition function of a one dimensional gas of particles trapped in an external potential $V$ and interacting through repulsive two-body interactions of the type $\ln \big[ \sinh[\pi \om_1(\la-\m ... More Presented by Dr. Karol KOZLOWSKI on 15 Sep 2014 at 16:30 Type: Plenary Talk Session: Tuesday morning The discovery of integrability in the planar limit of AdS/CFT has triggered a renewed interest toward the study of finite-size corrections of exactly solvable systems. In this talk, I will present a very recent idea which has made possible the reduction of the complicated Thermodynamic Bethe Ansatz equations for the anomalous dimensions of composite operators in$AdS_5/CFT_4$and in$Ad ... More
Presented by Roberto TATEO on 16 Sep 2014 at 11:00
Type: Plenary Talk Session: Monday morning
I am going to present some results about (p,q) Minimal Liouville gravity. It is assumed that the generating function of the correlators in genus zero in Minimal Liouville gravity (MLG) is nothing but logarithm of the Sato tau-function for dispersionless Gefand-Dikii hierarchy with the special initial condition given by Douglas string equation. Using the connection between MLG and Frobenious ... More
Presented by Prof. Alexander BELAVIN on 15 Sep 2014 at 10:00
Type: Plenary Talk Session: Wednesday morning
In this talk I will show that the entanglement entropy of a region of large size ℓ in a one-dimensional non-unitary critical model behaves as S∼(ceff/3)logℓ, where ceff=c−24Δ>0 is the effective central charge, c (which may be negative) is the central charge of the conformal field theory and Δ≤0 is the lowest holomorphic conformal dimension in the theory. This result generalize the well ... More
Presented by Dr. Benjamin DOYON on 17 Sep 2014 at 09:00
Type: Plenary Talk Session: Monday afternoon
We present a new approach to computing energy flow correlations in a generic CFT. These infrared finite observables are familiar from collider physics studies and describe the angular distribution of energy in outgoing radiation created from the vacuum by some source. The energy correlations can be expressed in terms of Wightman correlation functions in a certain limit. We explain how to compute t ... More
Presented by Gregory KORCHEMSKY on 15 Sep 2014 at 14:30
Type: Plenary Talk Session: Wednesday afternoon
Presented by Dr. Robert WESTON on 17 Sep 2014 at 14:30
Type: Talk Session: Thursday morning
We will consider interfaces of systems of classical statistical mechanics in two dimensions. Interfaces at criticality are conformally invariant random curves and SLE together with field theory have been successfully applied to several models. On the other hand, below criticality exact results are available only from lattice calculations which are restricted to the Ising model, a circumstance that ... More
Presented by Alessio SQUARCINI on 18 Sep 2014 at 10:00
Type: Poster Session: Discussion - Posters
We compute the null cusp anomalous dimension of ABJM theory at strong coupling up to two-loop order. This is done by evaluating corrections to the corresponding superstring partition function, weighted by the AdS4xCP3 action in AdS light-cone gauge. We compare our result, where we use an anomalous shift in the AdS4 radius, with the cusp anomaly of N=4 SYM, and extract the two-loop contribution to ... More
Presented by Mr. Edoardo VESCOVI on 15 Sep 2014 at 14:10
Type: Talk Session: Tuesday morning
We study the asymptotic behaviour of the dynamical correlation functions of massless quantum integrable models. We develop an approach based on the summation of the appropriate (critical) form factors. We show that this approach gives rise to a number of new hypergeometric identities. These identities lead to the leading terms of the asymptotics for the two-point and multi-point correlation funct ... More
Presented by Prof. Nikolai KITANINE on 16 Sep 2014 at 12:00
Type: Poster Session: Discussion - Posters
We map a system of one-dimensional guides containing bosons with strongly repulsive interaction onto the topological Kondo model. We study the thermodynamic properties by computing the ground state energy and the temperature dependence of the free energy shift due to the junction.
Presented by Dr. Francesco BUCCHERI on 15 Sep 2014 at 13:50
Type: Talk Session: Tuesday afternoon
In closed integrable systems, thermalization after a quantum quench is precluded by the existence of infinitely many conserved charges. The idea of the generalized Gibbs ensemble (GGE) is to include all local conserved charges into the canonical density operator with appropriate Lagrange-multipliers to ensure conservation of local charges. It is a nontrivial question whether the GGE correctly desc ... More
Presented by Mr. Márton MESTYáN on 16 Sep 2014 at 16:30
Type: Talk Session: Wednesday afternoon
We study the excited state subsystem purity (equivalent to 2nd Renyi entropy) as a measure of entanglement in 1+1d conformal field theories. In order to access the highly excited states we generalize the replica approach and develop a systematic framework to treat arbitrary states (in particular descendants) by means of novel CFT techniques including transformation of descendant fields under confo ... More
Presented by Tamas Vencel PALMAI on 17 Sep 2014 at 16:30
Type: Talk Session: Wednesday afternoon
We generalize the idea of 1307.6856 to build conformal blocks of a generic CFT (in dimension d>2) using a recurrence relation, idea which has roots in a paper by Zamolodchikov (1984) originally applied to Virasoro blocks in 2 dimensions. Generalizing this construction we are able to find a recurrence relation to build conformal blocks associated to the four point function of vector operators.
Presented by Mr. Emilio TREVISANI on 17 Sep 2014 at 16:00
Type: Talk Session: Tuesday morning
We discuss a connection between classical (1+1)-dimensional A_{n}^{(1)} affine Toda field theories (ATFTs) and Bethe Ansatz systems. We show that the connection coefficients for specific solutions of the associated linear problem for the classical ATFTs satisfy certain functional relations. This way we enlarge the so-called ODE/IM correspondence. Based on: P. Adamopoulou, C. Dunning 2014 Bethe ... More
Presented by Dr. Panagiota ADAMOPOULOU on 16 Sep 2014 at 10:00
Type: Talk Session: Tuesday afternoon
Interactions are known to have dramatic effects on bosonic gases in low dimension: Not only does the ground state transform from a condensate-like state to an effective Fermi sea, but new fundamental excitations are predicted to appear which do not have any higher-dimensional equivalents. In this work, we trace these elusive excitations via their effects on the dynamical structure factor of arrays ... More
Presented by Milosz PANFIL on 16 Sep 2014 at 16:00
Type: Talk Session: Monday afternoon
We propose a new type of experimentally feasible quantum quench protocol. A quantum system is prepared in a coherent, localized excited state of a Hamiltonian, whose interaction strength is characterized by a control parameter. At some point during the evolution of this solitonic excitation, the parameter is suddenly changed. We study the dynamics of solitons after this global quench in a semi-cla ... More
Presented by Fabio FRANCHINI on 15 Sep 2014 at 16:00
Type: Plenary Talk Session: Thursday morning
Presented by Prof. German SIERRA on 18 Sep 2014 at 09:00
Type: Plenary Talk Session: Tuesday morning
Presented by Dr. Nikolay GROMOV on 16 Sep 2014 at 09:00
Type: Plenary Talk Session: Tuesday afternoon
I will discuss in simple terms some topics emerging from recent studies of quantum systems driven away from equilibrium. Particular emphasis will be given to the integrable/non-integrable nature of the Hamiltonian and to its local properties.
Presented by Giuseppe MUSSARDO on 16 Sep 2014 at 14:30
Type: Plenary Talk Session: Thursday morning
Presented by Prof. Paul PEARCE on 18 Sep 2014 at 11:00
Type: Plenary Talk Session: Wednesday morning
Recently an efficient numerical method has been developed to implement crossing symmetry and unitarity on the operator dimensions and on OPE coefficients in CFTs in various dimensions. These calculations can be done only for theories lying at the boundary of the allowed parameter space. I illustrate an alternative method that can be applied to a larger class of CFTs, whether unitary or not, thoug ... More
Presented by Ferdinando GLIOZZI on 17 Sep 2014 at 11:30
Type: Talk Session: Wednesday morning
In this talks I will present new (unpublished) results regarding the entanglement entropy of one of the simplest integrable models: the Lee-Yang theory. Despite its simplicity, the Lee-Yang theory is non-unitary. One of the most famous consequences of this non-unitarity was the realization by Zamolodchikov that the form factor expansion of correlation functions is now given in terms of an alternat ... More
Presented by Dr. Olalla CASTRO ALVAREDO on 17 Sep 2014 at 11:00
Type: Talk Session: Wednesday morning
We analytically evaluate the R ́enyi entropy for the Forrester-Baxter RSOS models in the regime III. These models are lattice realisations of non-unitary minimal models of CFT. By studying the leading term of this expression it is possible to probe conformal properties of the ground state. Our results agree completely with recent CFT redictions for the entanglement entropy of non-unitary systems. ... More
Presented by Mr. Davide BIANCHINI on 17 Sep 2014 at 10:00
Type: Poster Session: Discussion - Posters
Within the framework of the AdS_5 /CFT_4 correspondence, the GKP string living on a AdS_5 ⊗ S^5 background finds a counterpart in the antiferromagnetic vacuum state for the spin chain, fruitfully employed to investigate the dual N = 4 SYM superconformal gauge theory. Integrability underlying such a model allows us to analyse the excitations over the vacuum considered, by computing their sca ... More
Presented by Simone PISCAGLIA on 15 Sep 2014 at 13:30
Type: Plenary Talk Session: Monday morning
Presented by Konstantin ZAREMBO on 15 Sep 2014 at 11:30