ar X iv : c on d - m at / 9 51 10 37 v 1 7 N ov 1 99 5 CELLULAR AUTOMATA FOR TRAFFIC FLOW : ANALYTICAL RESULTS

ar X iv : c on d - m at / 9 51 21 19 v 1 1 5 D ec 1 99 5 Two Lane Traffic Simulations using Cellular Automata

We examine a simple two lane cellular automaton based upon the single lane CA introduced by Nagel and Schreckenberg. We point out important parameters defining the shape of the fundamental diagram. Moreover we investigate the importance of stochastic elements with respect to real life traffic.

ar X iv : c on d - m at / 9 51 10 29 v 2 1 3 N ov 1 99 5 Spin gap in CaV 4 O 9 : a large S approach Marc

We study the stability of the 4-site plaquette order in a model recently introduced by Katoh and Imada to explain the spin gap observed in CaV4O9. We show that all relevant types of order (4-site plaquette, dimerized, Néel) can be described within the framework of Schwinger boson mean field theory, and we make predictions regarding their relative stability. The results are compared to exact dia...

ar X iv : g r - qc / 9 51 10 48 v 1 1 6 N ov 1 99 5 Two lectures on Two - Dimensional Gravity ∗

ar X iv : c on d - m at / 9 51 10 67 v 1 1 4 N ov 1 99 5 Excitonic Phase Transition in Electronic Systems

Although predicted theoretically excitonic phase transitions have never been observed. Recently it has been claimed that they can occur in some strongly correlated materials. We study the possibility of an excitonic transition in a two-band model and show that a true phase transition never occurs in the presence of hybridization. We suggest an

ar X iv : c on d - m at / 9 51 10 18 v 1 3 N ov 1 99 5 Spectral Flow in Josephson Junctions and Effective Magnus Force

Momentum production during the phase slip process in SNS Joseph-son junction is discussed. It is caused by the spectral flow of bound states of fermions localized within the junction. This effectively reduces the Magnus force acting on vortices which provides an explanation for the experimental observation of the negligible Magnus force in 2D Josephson junction arrays. The flow of the fermionic...