Generalized quantum no-go theorems of pure states

Hui-Ran Li, Ming‐Xing Luo, Hong Lai

Ming‐Xing Luo, Hui-Ran Li, Hong Lai +1 more

Andréa Oldofredi

Ludovico Lami, Bartosz Regula, Alexander Streltsov

Not all entanglement is distillable, i.e., extractable in pure form. In this work, the authors show that being assisted by catalysts, which generally can help transform quantum states, is not enough to change this; certain entangled states will stay ``bound entangled'' even when catalysts are allowed.

Somshubhro Bandyopadhyay

The superposition principle is fundamental to quantum theory. Yet a recent no-go theorem has proved that quantum theory forbids superposition of unknown quantum states, even with nonzero probability. The implications of this result, however, remain poorly understood so far. In this paper we show that the existence of a protocol that superposes two unknown pure states with nonzero probability (allowed to vary over input states) leads to violation of other no-go theorems. In particular, such a protocol can be used to perform certain state discrimination and cloning tasks that are forbidden not only in quantum theory but in no-signaling theories as well.

Danko Dimchev Georgiev