Understand
Quantum channels underlie the dynamics of quantum systems, but in many practical settings it is the channels themselves that require processing.
- We establish universal limitations on the processing of both quantum states and channels, expressed in the form of no-go theorems and quantitative bounds for the manipulation of general quantum channel resources under the most general transformation protocols.
- Focusing on the class of distillation tasks -- which can be understood either as the purification of noisy channels into unitary ones, or the extraction of state-based resources from channels -- we develop fundamental restrictions on the error incurred in such transformations and comprehensive lower bounds for the overhead of any distillation protocol.
- In the asymptotic setting, our results yield broadly applicable bounds for rates of distillation.