# LSV Seminar

The LSV seminar takes place on Tuesday at 11:00 AM. The usual location is the conference room at Pavillon des Jardins (venue).
If you wish to be informed by e-mail about upcoming seminars, please contact Stéphane Le Roux and Matthias Fuegger.

The seminar is open to public and does not require any form of registration.

## Past Seminars

### Quantum Digital Physics?

- Date
- Tuesday, June 20 2017 at 11:00AM
- Place
- Salle de Conférence (Pavillon des Jardins)
- Speaker
- Pablo Arrighi (LIF, Université Aix-Marseille)

The 60's 'Digital Physics' program advocates
that space may be nothing but a grid, with each cell containing a bounded amount
of bits of information, and the whole thing evolving in discrete time steps according
to a local rule. Thus according to this somewhat reductionist view the universe is but
a cellular automaton. At least two things are wrong with this picture. First, general
relativity tells us that the space should at least be a graph, and that this graph should
evolve under the local rule. Second, quantum theory tells us that the graph may well evolve
into a quantum superposition of graphs, and that this overall evolution should be unitary.
This suggests a 2020's 'Quantum Digital Physics' program modelling space as superpostions
of graphs, and time-evolution as a unitary causal operator. A theorem shows that such
time-evolutions take the form of a quantum circuit of finite depth.