R P KAUR, K TANKESHWAR and K N PATHAK

Department of Physics, Panjab University, Chandigarh 160 014, India

 Abstract.

Expressions for transverse and longitudinal current--current correlation functions of an ideal Fermi gas describing the current fluctuations induced in the electron system by external probe perpendicular and parallel to the propagation of electron wave, have been obtained at finite temperature. The results obtained for transverse and longitudinal functions are presented for different values of wavelength and frequency at different temperatures. The diamagnetic susceptibility as a function of temperature has also been obtained from transverse current correlation function as its long wavelength and static limit, which smoothly cross over from known quantum values to the classical limit with increase in temperature. 

Keywords:  Fermi gas; diamagnetic susceptibility; current correlations.

Pacs Nos.  71.10.-w; 71.10.Ca; 71.45.Gm