相关论文: Analytic calculation of field-strength correlators

We use Glauber's correlation function as well as the Green functions formalism to investigate, in the case of a dipolar atomic transition, the causal behaviour of the spontaneously emitted electromagnetic field, in the A.p coupling. This…

We consider the complex scalar field coupled to background NC U(1) YM and calculate the correlator of two gauge invariant composite operators. We show how the noncommutative gauge invariance is restored for higher correlators (though the…

In this letter we consider expectation values of local correlators in highly excited states of the spin-1/2 XXZ chain. Assuming that the string hypothesis holds we formulate the following conjecture: The correlation functions can be…

We consider an electron coupled to a random magnetic field with local correlations and eventually non-zero average value. Starting from the source-term formalism of Levine, Libby and Pruisken, we define a generating function for static…

A 'forward walking' Green's Function Monte Carlo algorithm is used to obtain expectation values for SU(3) lattice Yang-Mills theory in (3+1) dimensions. The ground state energy and Wilson loops are calculated, and the finite-size scaling…

We develop a field-theoretic description of large-scale structure formation by taking the non-relativistic limit of a canonically transformed, real scalar field which is minimally coupled to scalar gravitational perturbations in…

An exact representation of the causal QED fermion Green's function, in an arbritrary external electromagnetic field, derived by Fried, Gabellini and McKellar, and which naturally allows for non-perturbative approximations, is here used to…

The gauge invariant two-point correlator for the gluon field strength tensor is analysed by means of the QCD sum rule method. To this end, we make use of a relation of this correlator to a two-point function for a quark-gluon hybrid in the…

According to recent Quantum Monte Carlo simulations the small polaron theory is practically exact in a wide range of the long-range (Frohlich) electron-phonon coupling and adiabatic ratio. We apply the Lang-Firsov transformation to convert…

Momentum exchange between a heavy quark and a hot quark-gluon medium can be characterized nonperturbatively in terms of field-strength field-strength (E-E and B-B) correlators along a Polyakov loop. These can be studied on the lattice and…

In quantum field theory, the Green function is usually calculated as the expectation value of the time-ordered product of fields over the vacuum. In some cases, especially in degenerate systems, expectation values over general states are…

In this paper we begin the development of a formalism for the description of high energy neutrino interactions. It is based upon field theory quantized on a null plane. We set up the general formalism as well as some techniques needed to…

By the appropriate use of the Fock-Schwinger gauge properties, we derive the closed integral form of the `point-split' non-local background gauge connection originally expressed as a finite sum. This is achieved in the limit when the finite…

We calculate the vector and axial-vector current correlators in the coordinate space and compare them with the experimental information obtained through the spectral functions of hadronic tau decays measured by ALEPH. Lattice data are…

We compute the momentum- and frequency-dependent longitudinal spin structure factor for the one-dimensional spin-1/2 $XXZ$ Heisenberg spin chain in a magnetic field, using exact determinant representations for form factors on the lattice.…

String field theories exhibit exponential suppression of interactions among the component fields at high energies due to infinite-derivative factors such as $e^{\ell^2 \Box / 2}$ in the vertices. This nonlocality has hindered the…

The Galilei-covariant fermionic field theories are quantized by using the path-integral method and five-dimensional Lorentz-like covariant expressions of non-relativistic field equations. Firstly, we review the five-dimensional approach to…

Bound states of heavy quarks are considered. Using the path integral formalism we are able to rederive, in a gauge invariant way, the Leutwyler-Voloshin short distance analysis as well as a long distance linear potential. At all distances…

We use gauge/string duality to analytically evaluate correlation lengths of the renormalized field strength correlators in pure Yang-Mills theories at zero and finite temperature.

Green's functions are gauge-dependent quantities. Thus, the manifestation of confinement in these correlation functions also depends on the gauge. Here we use lattice gauge theory to study the gluon and the ghost propagators in a gauge (the…