Quantum Causal Graph Dynamics
Abstract
Suppose that an entire graph evolves quantum mechanically and gets driven into superpositions of graphs of different connectivities and node populations. Suppose moreover that the evolution is causal, meaning that information can only propagate at a bounded speed, with respect to graph distance. We show that this quantum evolution must decompose into small, local unitary rewritings of graph disks. This unifies a result on Quantum Cellular Automata with another on Reversible Causal Graph Dynamics. To reach the result we formalize a notion of causality which is valid in the context of quantum superpositions of time-varying graphs, and has a number of good properties.
Please note that the meeting will be recorded and live-streamed to YouTube:
Pablo Arrighi
Professor
Pablo Arrighi studied at Imperial College, London, and defended his doctoral thesis at Cambridge University in 2003. He was appointed Maître de Conférences at the Université Grenoble-Alpes in 2005, Professor at Aix-Marseille Université in 2014, and finally Professor at the Université Paris-Saclay in 2020.
During his thesis, Pablo Arrighi described the first blind quantum computation protocol. He then pioneered the study of quantum programming languages. He next became one of the founders of the field of quantum cellular automata, i.e. discrete space discrete time quantum mechanics. His research also draws bridges between quantum networks and quantum gravity eg through the QISS consortium.