Tunneling into a Fractional Quantum Hall System and the Infrared Catastrophe

We calculate the tunneling density of states of a two-dimensional interacting electron gas in a quantizing magnetic field. We show that the observed pseudogap in the density of states can be understood as the result of an infrared catastrophe in a noninteracting electron model. This catastrophe stems from the response of an electronic system to the potential produced by the abruptly added charge during a tunneling event. Our formalism can be applied at any filling factor without the use of Chern-Simons or composite fermion theory

Quantum Breathing Mode for Electrons with 1/r^2 Interaction

We discuss a collective "breathing" mode of electrons with inverse-square-law interactions in a two-dimensional quantum dot and a perpendicular magnetic field.Comment: 1 page, Revtex, submitted to "Comment" Section of Phys. Rev. Let