## Objective

One of the main problems of modern theoretical physics is to construct a consistent theory of Quantum Gravity (QG). Great achievements were done in this direction using non-perturbative quantization techniques (Spinfoam-Loop Quantum Gravity). If the mathem atical framework is getting well understood, it is not completely clear how one should make contact with the forthcoming experiments (GLAST, AUGER) trying to measure some QG effects.

The key points to make a contact between experiment and theory are for example the notion of Deformed Special Relativity, or the notion of Quantum Reference Frame. A reference frame is necessary in General Relativity to make predictions (see e.g. the Global Positioning System). One needs then to define their alter-ego in the quantum context. This prompts the idea of Quantum Geometry or Non-Commutative Geometry. This is a notion I intend to explore. With the current proposed experiments one doesn't expect to probe the full regime of QG, it is therefore crucial to understand how the quantum effects are renormalized to a scale far from the Planck length.

In fact the renormalization idea is also a key idea in Deformed Special Relativity (DSR). In some sense this theory is the one that experiments are going to probe as it can be considered as a low energy limit of QG. It is also an example of a Non commutative geometry. We intend to study these different aspects of renormalization or classical limit, in the realm of pure quantum Gravity or more in an effective way in the DSR setting.

It is interesting that some of the problems, or mathematical techniques met in the QG setting are also found in Quantum Information Theory (QIT), and Quantum Computing. For example the notion of Quantum Reference Frame is already existing in QI. We intend to create some more concrete interactions between the two fields, so that one can expect to have some new concepts and techniques to emerge, for the benefit of all.

### Field of science

- /natural sciences/physical sciences/theoretical physics
- /natural sciences/mathematics/pure mathematics/geometry
- /engineering and technology/electrical engineering, electronic engineering, information engineering/electronic engineering/computer hardware/quantum computer

### Call for proposal

FP6-2002-MOBILITY-5

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