QUANTUM DEPHASING BY CHAOS

We examine whether the chaotic behavior of classical systems with a li mited number of degrees of freedom can produce quantum dephasing, agai nst the conventional idea that dephasing takes place only in large sys tems with a huge number of constituents and complicated internal inter actions. On the basis of this analysis, we briefly discuss the possibi lity of defining quantum chaos and of inventing a ''chaos detector''.