You are cordially invited to the SCL online seminar of the Center for the Study of Complex Systems, which will be held on Thursday, 30 May 2024 at 14:00 on Zoom (the link is given below). The talk entitled

An inherent instability of unitary quantum dynamics

will be given by Dr. Jasper van Wezel (Institute for Theoretical Physics, University of Amsterdam, The Netherlands). The abstract of the talk:

In this talk we will show that unitary quantum dynamics as described by Schrodinger's equation is inherently unstable. In close analogy to the well-known description of spontaneous symmetry breaking, the dynamics of quantum systems in the thermodynamic limit is infinitely sensitive to even infinitesimally small perturbations of its unitary time evolution. For finite-sized quantum objects, this results in qualitative changes of the dynamics if even exceedingly small perturbations of the unitary dynamics are allowed. We will argue that such small perturbations may indeed be expected to exist and indicate how this affects model descriptions of microscopic and macroscopic objects, as well as systems on the nanoscale. The question that then remains is whether such effects are observable in practice as well as in principle. We will give some arguments for why and how instabilities might show up in existing and recently proposed nanoscale experiments and indicate the main problems that are to be overcome in order for the instability to be distinguishable from generic effects in the quantum dynamics of open systems.

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