CPHT Condensed Matter seminar

Tuesday, February 21 at 14:00 at CPHT,

Conference room Louis Michel

Irenée Frerot (Institute Néel, CNRS, Grenoble)

Bell's inequalities for many-body systems

Abstract : The violation of Bell's inequalities (BI) is a fundamental manifestation of quantum entanglement. Over the recent years, its was progressively recognized that BI allow one to probe fine features of quantum entanglement in many-body systems from minimal assumptions regarding the details of the experimental implementation. I will present the conceptual framework to investigate BI in multipartite systems, as well as the computational challenges associated to the construction of relevant many-body BI. I will present recently-developed approaches, inspired by so-called inverse problems of statistical physics, to overcome this challenge. I will discuss new BI tailored to specific families of quantum many-body states, such as spin-squeezed or spin singlet states. I will conclude by mentioning the self-testing phenomenon, in which the maximal violation of tailored BI allow one to make strong statements on the structure of the prepared quantum state and measurements from minimal assumptions, in a many-body context. Although still delicate for both theory and experiments, the concept of self-testing might become in the future an important tool for the certification of quantum computation devices.