Renormalized Functional Renormalization Group

We construct a new version of the effective average action together with its flow equation. The construction entails in particular the consistency of fluctuation field and background field equations of motion, even for finite renormalization group scales. Here we focus on the quantum gravity application, while the generalization of this idea to gauge theories is obvious. Our approach has immediate impact on the background field approximation, which is the most prominent approximation scheme within the asymptotic safety scenario. We outline the calculation of quantum gravity observables from first principles using the new effective average action.Comment: 5+1 page

Labour Turnover in Russia: Evidence from the Administrative Reporting of Enterprises in Four Regions

Early in the 1990s, the introduction of economic reforms in Russia created expectations of a substantial reallocation of labour; "old" jobs in the state and former-state sector were to be shed and "new" jobs created in new private firms. Although the labour market experienced relatively heavy flows, they did not occur in the expected pattern. Most of the separations were quits rather than lay-offs and former-state enterprises continued to hire at relatively high rates. This paper takes a fresh look at the developments in labour turnover and the relationship between the components of labour turnover and various enterprise characteristics. National-level aggregate statistics are used to gain insights concerning the scale and structure of labour turnover in medium and large enterprises. A more detailed examination is then made of the components of labour turnover and their relationship to selected enterprise characteristics using microdata from administrative reporting in four Russian regions.Labour Turnovers, Hirings, Separations, Employment, Microdata, Russian Regions

The Gravitational Two-Loop Counterterm is Asymptotically Safe

Weinberg's asymptotic safety scenario provides an elegant mechanism to construct a quantum theory of gravity within the framework of quantum field theory based on a non-Gau{\ss}ian fixed point of the renormalization group flow. In this work we report novel evidence for the validity of this scenario, using functional renormalization group techniques to determine the renormalization group flow of the Einstein-Hilbert action supplemented by the two-loop counterterm found by Goroff and Sagnotti. The resulting system of beta functions comprises three scale-dependent coupling constants and exhibits a non-Gau{\ss}ian fixed point which constitutes the natural extension of the one found at the level of the Einstein-Hilbert action. The fixed point exhibits two ultraviolet attractive and one repulsive direction supporting a low-dimensional UV-critical hypersurface. Our result vanquishes the longstanding criticism that asymptotic safety will not survive once a "proper perturbative counterterm" is included in the projection space.Comment: 7 pages, 1 figur

Zooming in on fermions and quantum gravity

We zoom in on the microscopic dynamics for fermions and quantum gravity within the asymptotic-safety paradigm. A key finding of our study is the unavoidable presence of a nonminimal derivative coupling between the curvature and fermion fields in the ultraviolet. Its backreaction on the properties of the Reuter fixed point remains small for finite fermion numbers within a bounded range. This constitutes a nontrivial test of the asymptotic-safety scenario for gravity and fermionic matter, additionally supplemented by our studies of the momentum-dependent vertex flow which indicate the subleading nature of higher-derivative couplings. Moreover our study provides further indications that the critical surface of the Reuter fixed point has a low dimensionality even in the presence of matter.Comment: 25 pages, 15 figure

How perturbative is quantum gravity?

We explore asymptotic safety of gravity-matter systems, discovering indications for a near-perturbative nature of these systems in the ultraviolet. Our results are based on the dynamical emergence of effective universality at the asymptotically safe fixed point. Our findings support the conjecture that an asymptotically safe completion of the Standard Model with gravity could be realized in a near-perturbative setting.Comment: 6 pages, 3 figure