Matter matters in asymptotically safe quantum gravity

The Functional
Renormalisation Group technique has received great attention in recent times
proving itself as a powerful tool to describe the high energy behaviour of
gravitational interactions.

Its key ingredient is a nontrivial fixed point of the theory renormalization
group flow which controls the behavior of the coupling constants in the
ultraviolet regime and ensures that physical quantities are safe from
divergences. I will briefly review the main ingredients of the gravitational asymptotic
safety framework before focusing on the effect of massless minimally coupled
scalars, fermions and vector fields on the gravitational fixed point. I will
then set bounds on the type and number of such fields requiring the existence
of a UV attractive fixed point. I will also discuss the dynamically generated quantum-gravity scale in
asymptotic safety, which is the transition scale to the fixed-point regime, and
its variation as a function of matter degrees of freedom. To conclude I will also consider the case of higher dimensional models.

Event Type: 
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Event Date: 
Jeudi, Novembre 7, 2013 - 14:30 to 16:00
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