Leibniz Universität Hannover

## Talks by Cédric Bény

## An axiomatic avenue to AdS/CFT

Cédric Bény
Leibniz Universität Hannover

I will review a recent proposal for a top-down approach to AdS/CFT by A. Schwarz, which has the advantage of requiring few assumptions or extraneous knowledge, and may be of benefit to information theorists interested by the connections with tensor networks. I will also discuss ways to extend this approach from the Euclidean formalism to a real-time picture, and potential relationships with MERA.

## Tangent field theory

Cédric Bény
Leibniz Universität Hannover

The modern understanding of quantum field theory underlines its effective nature: it describes only those properties of a system relevant above a certain scale. A detailed understanding of the nature of the neglected information is essential for a full application of quantum information-theoretic tools to continuum theories.
I will present an operationally motivated method for deriving an effective field theory from any microscopic description of a state. The approach is based on dimensional reduction relative to a quantum distinguishability metric.

## Causal Structure of MERA

Cédric Bény
Leibniz Universität Hannover

The multiscale entanglement renormalization ansatz can be reformulated in terms of a causality constraint on discrete quantum dynamics. This causal structure is that of de Sitter space with a flat spacelike boundary, where the volume of a spacetime region corresponds to the number of variational parameters it contains.

## Unsharp pointer observables and the structure of decoherence

Cédric Bény
Leibniz Universität Hannover

Decoherence attempts to explain the emergent classical behaviour of a
quantum system interacting with its quantum environment. In order to
formalize this mechanism we introduce the idea that the information
preserved in an open quantum evolution (or channel) can be
characterized in terms of observables of the initial system. We use
this approach to show that information which is broadcast into many
parts of the environment can be encoded in a single observable. This
supports a model of decoherence where the pointer observable can be an
arbitrary positive operator-valued measure (POVM).

## Information Flow in the Heisenberg Picture

Cédric Bény
Leibniz Universität Hannover