Long-range Coulomb interaction and frequency dependence of shot noise in mesoscopic diffusive contacts

The frequency dependence of shot noise in mesoscopic diffusive contacts is calculated with account taken of long-range Coulomb interaction and external screening. While the low-frequency noise is $1/3$ of the noise of classical Poisson process independently of the contact shape, the high-frequency noise tends to the full classical value for long and narrow contacts because of strong screening by the surrounding medium. In this case, the current fluctuations at opposite ends of the contact are completely independent.