We study transport in coherent conductors driven by a time-periodic bias voltage. We present results of the charge and energy noise and complement them by a study of the mixed noise, namely the zero-frequency correlator between charge and energy current. The mixed noise presents interference contributions and transport contributions, showing features different from those of charge and energy no...

We introduce a new sum-rule for large-N c QCD which relates the density of heavy quarkonium states, the state-averaged square of the wave-function at the origin, and the heavy quark current-current correlator. Focusing on the region of energy just above perturbative threshold, we calculate the correlator by incorporating arbitrarily high orders in the QCD coupling α s. We use the sum-rule to de...

We present the result for the first moment of the scalar and axial-vector current correlator in third order of the strong coupling constant αs and give the details of a recent evaluation of the pseudo-scalar correlator. The results can be used to reduce the theoretical uncertainty due to higher order corrections for the determination of fundamental parameters of QCD in the context of lattice ca...

We measure current fluctuations of mesoscopic devices in the quantum regime, when the frequency is of the order of or higher than the applied voltage or temperature. Detection is designed to probe separately the absorption and emission contributions of current fluctuations, i.e. the positive and negative frequencies of the Fourier transformed nonsymmetrized noise correlator. It relies on measur...

The running charm-quark mass in the MS scheme is determined from weighted finite energy QCD sum rules (FESR) involving the vector current correlator. Only the short distance expansion of this correlator is used, together with integration kernels (weights) involving positive powers of s, the squared energy. The optimal kernels are found to be a simple pinched kernel, and polynomials of the Legen...

In this contribution three-loop QCD corrections to current correlators are considered. The application of the large momentum procedure, which provides a systematic expansion in (m/q), allows the computation of terms up to n = 6 for the vector and axial-vector correlator and up to n = 4 for the scalar and pseudo-scalar correlator. Some physical applications are discussed. There are plenty of imp...

The mixed-isospin vector current correlator, h0jT(V V !)j0i is evaluated using both QCD sum rules and Chiral Perturbation Theory (ChPT) to one-loop order. The sum rule treatment is a modiication of previous analyses necessitated by the observation that those analyses produce forms of the correlator that fail to be dominated, near q 2 = 0, by the most nearby singularities. Inclusion of contribut...

Two-loop contributions to the anomalous correlation function 〈Jμ(x)Jν(y)Jρ(z)〉 of three chiral currents are calculated by a method based on the conformal properties of massless field theories. The method was previously applied to virtual photon diagrams in quantum electrodynamics, and it is extended here to diagrams with scalars and chiral spinors in the abelian Higgs model and in the SU(3) × S...

where the field strength F a μν = ∂μA a ν − ∂νA a μ + gfAμA c ν , z = y− x and P denotes path ordering of the exponential. In general, the gauge invariant field strength correlator could be defined with an arbitrary gauge string connecting the end points x and y, but in this work we shall restrict ourselves to a straight line. It is the basic ingredient in the stochastic model of the QCD vacuum...

We measure the current fluctuations emitted by a normal-metal-insulator-normal-metal tunnel junction with a very wide bandwidth, from 0.3 to 13 GHz, down to very low temperature T=35  mK. This allows us to perform the spectroscopy (i.e., measure the frequency dependence) of thermal noise (no dc bias, variable temperature) and shot noise (low temperature, variable dc voltage bias). Because of th...