Quantum catalysis of information

In quantum information science, it has been long believed that no one can access quantum information in a system without disturbing it. In fact, the belief has been corroborated by several no-go theorems such as the no-cloning theorem and the no-deleting theorem. Here, however, we show that the belief is incorrect, by exhibiting a novel process, `quantum catalysis of information', in which, without receiving any disturbance, a system certainly exchanges a type of information that cannot be transmitted without quantum communication channel.