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14:00 to 14:30 |
Spenta Wadia (ICTS-TIFR, India) |
Planar Diagrams and Random Matrix Theory We will summarize some of Parisi's contributions to the large N limit of quantum field theory and matrix models.
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14:30 to 15:00 |
V. Ravindran (IMSc, India) |
Infrared Structure of SU(N) Gauge Theory Higher order radiative corrections, in particular from Quantum Chromodynamics (QCD), play an important role at the Large Hadron Collider (LHC). They also exhibit rich perturbative structure of the underlying quantum field theory. In this talk, we will discuss the universal infrared structure and the factorisation properties of on-shell scattering amplitudes and cross sections in perturbative QCD and demonstrate how they are useful to resume certain large logarithms that spoil the prediction of fixed order computations. We present few applications in the context of inclusive and semi inclusive productions of Higgs boson and the Drell-Yan pairs at the LHC
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15:00 to 16:00 |
Marc Mezard (ENS, France) |
Statistical Physics and Statistical Inference A major challenge of contemporary statistical inference is the large-scale limit, where one wants to discover the values of many hidden parameters, using large amounts of data. In recent years, ideas from statistical physics of disordered systems, notably the cavity method, have helped to develop new algorithms for important inference problems, ranging from compressed sensing to machine learning and generalized linear regression. The talk will review these developments and explain how they can be used, together with the replica method, to identify phase transitions in benchmark statistical ensembles of inference problems.
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16:00 to 17:00 |
Break |
Break |
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17:00 to 18:00 |
Irene Giardina (Sapienza University, Italy) |
The Statistical Physics of Flocks and Swarms Flocks and swarms represent iconic examples of living active matter, where motile interacting individuals give rise to emergent global patterns. Despite the great complexity of their biological components, these groups obey robust statistical laws and can be described within a statistical physics approach. In this talk I will review our current understanding of these systems. Using experimental evidence and theoretical modelling I will show how conservation laws, interactions and motility combine together leading to non-trivial dynamics and out-of-equilibrium features on the large scale. Our analysis explains the mechanistic origin of efficient collective behaviour in living groups and unveils new challenges in the statistical physics of active systems.
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18:00 to 19:00 |
Jorge Kurchan (ENS, France) |
The Replica-dynamic Correspondence in Finite Dimensions I have recently completed the last missing link between replicas and dynamics, along the lines of a paper by Franz, Mezard Parisi and Peliti. Effective temperatures are in a one-to-one correspondence with the X parameters of Parisi's ansatz, and dynamic ultrametricity is in a one-to-one correspondence with equilibrium ultrametricity. This correspondence, plus simple dynamic arguments, strongly suggest that time-reparametrization invariance is a central condition for the consistency of both approaches, and, furthermore, that a `sigma model' of reparametrizations may be a promising next step to make.
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19:00 to 20:00 |
Gilles Tarjus (Sorbonne Université, France) |
Supersymmetry, Dimensional Reduction and Avalanches in Random-field Models In 1979, Parisi and Sourlas in a beautiful 2-page paper related the critical behavior of the random-field Ising model (RFIM) to a supersymmetric scalar field theory and showed that the supersymmetry (SUSY) leads to a ‘dimensional reduction’ property by which the RFIM
behavior is identical to that of the Ising model without disorder in 2 dimensions less. It is however well established that the dimensional-reduction property breaks down in low dimensions. We relate this breakdown to the existence of scale-free avalanches in the ground state of the system at criticality and show how this long-distance physics can be described through a functional Renormalization Group. Formulating the functional RG in a superfield formalism enables us to follow the underlying SUSY and its spontaneous breaking along the RG flow and to identify a critical dimension below which dimensional reduction fails.
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