Speaker
Description
Quantum Field theories are a natural way to describe quantum many body systems. Irrelevant details of the microscopic physics are ignored and new relevant degrees of freedom, described by the QFT, emerge at a larger scale. I will illustrate this in the example of the emergence of the Sine-Gordon quantum field theory from the microscopic description of two tunnel coupled super fluids [1] and in the emergence of Pauli blocking in a weakly interacting Bose gas [2]. Special emphasis will be put on how to verify such emergent quantum simulators and how to characterize them. Thereby I will present two tools: High order correlation functions and their factorization [1], the evaluation of the quantum effective action and the momentum dependence of propagators and vertices (running couplings, renormalization of mass etc ..) of the emerging quantum field theory [3] and quantum field tomography that points to a new way to read out quantum simulators [4]. Together they establish general methods to analyse quantum systems through experiments and thus represents a crucial ingredient towards the implementation and verification of quantum simulators. As an example, I will report on the progress towards measuring area laws of mutual information and entanglement entropy in a QFT, and the study of information fronts in curved space time.
Work performed in collaboration with the groups of Th. Gasenzer und J. Berges (Heidelberg), Jens Eisert (FU Berlin) and E. Demler (Harvard). Supported by the DFG-FWF: SFB ISOQUANT: and the EU: ERC-AdG QuantumRelax
[1] T. Schweigler et al., Nature 545, 323 (2017), arXiv:1505.03126;
[3] F. Cataldine et al. arXiv:2111.13647;
[3] T. Zache et al. Phys. Rev. X 10, 011020 (2020);
[4] M. Gluza et al., Communication Physics 3, 12 (2020).
