Y. Takane et K. Nakamura, INFLUENCE OF SMALL-ANGLE DIFFRACTION ON THE BALLISTIC CONDUCTANCE FLUCTUATIONS IN CHAOTIC BILLIARDS, Journal of the Physical Society of Japan, 67(2), 1998, pp. 397-400
The ballistic conductance fluctuation (CF) in chaotic billiards are st
udied using an extended approximation. We show that the effect of smal
l-angle diffraction (SAD) on classical electron paths is essential for
describing the ballistic CF. By incorporating the SAD effect, we find
that both the diffuson and cooperon processes equally contribute to t
he variance of the transmission coefficient T, in contrast to the resu
lt by Jalabert et al. [Phys. Rev. Lett. 65 (1990) 2442] in which only
the diffuson process appears. Our result indicates that, in the presen
ce of a magnetic field. the variance of T decreases precisely by a fac
tor of two due to the sensitive suppression of the cooperon contributi
on. We also determine the full magnetic-field correlation function of
T.