I will discuss transport of electrons through quantum wires--nano-scale conductors in which the electrons are confined to one spatial dimension. Theory and experiments agree that the resis- tance of a quantum wire takes a universal value of h/2e2, where h is the Planck's constant, and e is the electron charge. However, a number of recent experiments show that in the regime of very low density of electrons in the wire the resistance increases by 40-100%. At such low densities the electrons repel each other very strongly, and may form a crystalline structure (Wigner crystal). In this regime the spins of electrons are nearly decoupled from each other, and the propagation of the spin excitations through the wire is suppressed. I will argue that this effect should result in doubling of the resistance of the wire.
Coffee and cookies before the presentation at 3:20 pm, and refreshments after the presentation will both be served in Room 128.