AC Properties of a Quantum Tube with Spin Orbit Interaction

In this talk I will discuss the ac properties of electrons in a tubular geometry with a spin orbit interaction SOI on a finite segment of the tube When the segment is connected to only one lead we study the properties of this RC circuit and in particular the effect of SOI on the capacitance and on the relaxation resistance We find for a certain range of parameters a peculiar negative capacitance Our results for the resistance agree with the universal resistance of Buttiker apart from sharp peaks in