An explicit expression for the generating functional of two–flavor low–energy QCD with external sources in the presence of non-vanishing nucleon densities has been derived recently [1]. Within this approach we derive power counting rules for the calculation of in-medium pion properties. We develop the so-called standard rules for residual nucleon energies of the order of the pion mass and a mod...

Surface and bulk critical properties of an aperiodic spin chain are investigated in the framework of the φ phenomenological Ginzburg-Landau theory. According to Luck’s criterion, the mean field correlation length exponent ν = 1/2 leads to a marginal behaviour when the wandering exponent of the sequence is ω = −1. This is the case of the Fibonacci sequence that we consider here. We calculate the...

Some general features of the scattering of boson-based anyons with an added non-statistical interaction are discussed. Periodicity requirements of the phase shifts are derived, and used to illustrate the danger inherent in separating these phase shifts into the well-known pure Aharanov-Bohm phase shifts, and an additional set which arise due to the interaction. It is proven that the added phase...

If the two-body interaction φ is sufficiently smooth, the behavior of the system for large N is well understood (Seee for instance Ref.s [1],[2],[3]). Namely, if the initial positions and velocities of the particles are independently and identically distributed according to the probability density f = f(x, v), in the limit N → ∞ each particle is distributed at time t according to the distributi...

Bertrand Berche†, Pierre Emmanuel Berche†‡, Ferenc Iglói§‖ and Gábor Palágyi¶ † Laboratoire de Physique des Matériaux , Université Henri Poincaré, Nancy 1 B.P. 239, F-54506 Vandœuvre les Nancy, France ‡ Institut für Physik, Johannes Gutenberg-Universität, Mainz Staudinger Weg 7, 55099 Mainz, Germany § Research Institute for Solid State Physics, H-1525 Budapest, P.O.Box 49, Hungary ‖ Institute f...

Inspired by the model of Nambu and Jona-Lasinio, various Lagrangians are considered for a system of interacting quarks. Employing standard techniques of many-body theory, the scalar part of the quark self-energy is calculated including terms up to second-order in the interaction. Results obtained for the single-particle Green’s function are compared with those which only account for the mean-fi...

We introduce a mean-field type approximation for description of company’s income statistics. Utilizing huge company data we show that a discrete version of Langevin equation with additive and multiplicative noises can appropriately describe the time evolution of a company’s income fluctuation in statistical sense. The Zipf’s law of income distribution is shown to be hold in a steady-sate widely...

A mean-field variant of the model of limit order driven market introduced recently by Maslov is formulated and solved. The agents do not have any strategies and the memory of the system is kept within the order book. We show that the evolution of the order book is governed by a matrix multiplicative process. The resulting stationary distribution of step-to-step price changes is calculated. It e...

We present a formulation of mean-field approximation for layered feed-forward stochastic networks. In this formulation, one can obtain not only estimates of averages for state variables of the networks but also those of intra-layer correlations, the latter of which cannot be obtained by the conventional mean-field approximation. Moreover, this formulation provides a framework to treat “conditio...

In a gauge-fixed language gluon-meson duality can be described as the Higgs mechanism for “spontaneous symmetry breaking” of color. We present a mean field computation which suggests that this phenomenon is plausible in QCD. One obtains realistic masses of the light mesons and baryons. e-mail: [email protected] A dual description of QCD in the low momentum or strong coupling ...