Scaling properties of universal conductance fluctuations in quasi ballistic narrow wires

We study the scaling properties of universal conductance fluctuations, observed in the magneto-resistance of quasi ballistic, split gate wires. In such devices the correlation field analysis is not simply determined by theoretical predictions for corresponding diffusive systems, and we discuss this breakdown in terms of a spreading of phase coherent electron interference, into the ungated regions of the devices. In order to characterise this effect we develop a simple model, in which the degree of spreading is represented by a single parameter γ. Performing this analysis we find that γ scales as a simple function of the wire length and width, enabling us to characterise the interplay of interference from the different regions of the split gate wire.