Séminaire de Physique Mathématique 13 février 2020
JEUDI 13 FEVRIER 14h SALLE LOUIS MICHEL
BALT VAN REES
QANTUM FIELD THEORY in ANTI-DE SITTER and the S-MATRIX
We discuss results obtained by considering gapped QFTs in a fixed Anti-de Sitter background. Much like in the AdS/CFT correspondence, we can naturally define
'boundary' observables that exhibit conformal invariance in one dimension less. These observables can be analyzed using conformal bootstrap techniques which results in new non-perturbative bounds on the strength of the coupling constants in a general QFT. When we send the AdS curvature to zero the boundary observables should morph into the S-matrix of the flat-space QFT. We will discuss the different ways in which this connection can be made explicit, and how it might end up teaching us new lessons about the non-perturbative structure of scattering amplitudes.
JEUDI 13 FEVRIER 15h15 SALLE LOUIS MICHEL
THE FOURTH PILLAR which QUANTUM MECHANICS RESTS UPON
Traditionally, the three concepts of states, observables and unitary evolution form the pillars Quantum Mechanics is built upon. It is well known that they do not suffice to solve, for example, the so-called measurement problem.
In this talk I will describe a fourth fundamental concept, proposed only recently, namely the "Principle of Diminishing Potentialities". I will then show how it enables one to come up with a precise notion of "events" in Quantum Mechanics and with a new understanding of the time evolution of states of isolated systems.
As results, the "measurement problem" and the unitarity- or information paradox disappear, and a "Quantum Mechanics without Observers" emerges.