Volume 77, Number 3, February 2007
Article Number 36002
Number of page(s) 5
Section Condensed Matter: Structural, Mechanical and Thermal Properties
Published online 22 January 2007
EPL, 77 (2007) 36002
DOI: 10.1209/0295-5075/77/36002

Shearing a fermionic gas and quantized friction

E. Granot

Department of Electrical and Electronics Engineering, College of Judea and Samaria - Ariel 44837, Israel

received 1 July 2006; accepted in final form 27 November 2006; published February 2007
published online 22 January 2007

The frictional forces in sheared fermionic gas are investigated. The gas is sheared by two sliding surfaces. Except for a small imperfection (bulge) on one of them, the surfaces are totally smooth. We show that when the bulge is extremely small, and the gas is also confined in the lateral dimension, the frictional force (F) is quantized. That is, $F=\mu _{F}v$, where v is the sliding velocity with respect to the lubricant gas, $\mu _{F}\equiv 2mn_{c}^{2}h$ is the friction coefficient, h is the Planck constant and m is an integer. It is also shown that the coefficient nc depends only on the bulge's properties (it does not depend on either the gas properties or the sliding velocity).

68.35.Af - Atomic scale friction .
71.10.Ca - Electron gas, Fermi gas .
07.79.Sp - Friction force microscopes .

© Europhysics Letters Association 2007