PÈNE , Olivier

We use an effective Lagrangian to study the multibody massless neutrino exchange inside a finite neutron star. Following Schwinger, we show how the total interaction energy density is computed by comparing the values of the zero-point energy of the neutrino sea with and without the star. Here we extend a previous one-dimensional toy computation...

The interaction due to the exchange of massless neutrinos between neutrons is a long-range force. Border effects on this multibody exchange inside a dense core are studied and computed analytically in dimensions. We demonstrate in this work that a proper treatment of the star's border effect automatically incorporates the condensate...

We study the high energy behaviour of fermions hitting a general wall caused by a first-order phase transition. The wall profile is introduced through a general analytic function. The reflection coefficient is computed in the high energy limit and expressed in terms of the poles of the wall profile function. It is shown that the leading...

We trace here instantons through the analysis of pure Yang-Mills gluon Green functions in the Landau gauge for a window of IR momenta (0.4

The next-to-leading-order (NLO) term in the operator product expansion (OPE) of the quark propagator vector part Zψ and the vertex function g1 of the vector current in the Landau gauge should be dominated by the same ⟨A2⟩ condensate as in the gluon propagator. On the other hand, the perturbative part has been calculated to a very high precision...

We give a more transparent understanding of the vacuum expectation value of the renormalized local operator A2 by relating it to the gluon propagator integrated over the momentum. The quadratically divergent perturbative contribution is subtracted and the remainder, dominantly due to the O(1/p2) correction to the perturbative propagator at...

We present a study of αMOM(p) at small p computed from the lattice in the quenched approximation (nf = 0). It shows a dramatic ∝ p4 law which can be understood within an instanton liquid model. In this framework the prefactor gives a direct measure of the instanton density in thermalised configurations. A preliminary result for this density is...

We argue that the ⟨A2OPE⟩ condensate found in the Landau gauge on lattices, when an operator product expansion of Green's functions is performed, might be explained by instantons. We use cooling to estimate the instanton contribution and extrapolate back the result to the thermalized configuration. The resulting ⟨A2inst⟩ is similar to ⟨A2OPE⟩.

Gluon two- and three-point Green Functions computed in Landau gauge from the lattice show the existence of power corrections to the purely perturbative expressions, that can be explained through an Operator Product Expansion as the influence of a non gauge invariant mass dimension two condensate. The relationship of this condensate with...