We ask what type of mixed quantum states can arise when a number of separated parties start by sharing a pure quantum state and then this pure state becomes contaminated by noise. We show that not all mixed states arise in this way. This is even the case if the separated parties actively try to degrade their initial pure state by arbitrary local actions and classical communication.
|Translated title of the contribution||Are all noisy quantum states obtained from pure ones?|
|Number of pages||3|
|Journal||Physical Review Letters|
|Publication status||Published - 3 Dec 2001|
Bibliographical notePublisher: American Physical Soc
Other identifier: IDS number 498ZZ