No cloning with unitary scaling

Abstract: It is known that the classical information like strings of bits can be copied. In 1982, Wootters and Zurek proposed the quantum no-cloning principle [1]. No-cloning principle says that it is impossible to make an identical copy of an arbitrary unknown quantum pure state by using unitary evolution. In this paper, we propose a general no-cloning principle. We call U|psi>, where U is any unitary operator, a U-copy of the state |psi>. The general no-cloning principle states that it is impossible to make a U-copy of an arbitrary unknown quantum pure state by using unitary evolution.