No-go theorems for quantum resource purification

          @misc{ pirsa_PIRSA:19110146,
            doi = {10.48660/19110146},
            url = {https://pirsa.org/19110146},
            author = {Liu, Zi-Wen},
            keywords = {Quantum Information},
            language = {en},
            title = {No-go theorems for quantum resource purification},
            publisher = {Perimeter Institute},
            year = {2019},
            month = {nov},
            note = {PIRSA:19110146 see, \url{https://pirsa.org}}
          }
          

Abstract

The manipulation of quantum "resources" such as entanglement and coherence lies at the heart of quantum advantages and technologies. In practice, a particularly important kind of manipulation is to "purify" the quantum resources, since they are inevitably contaminated by noises and thus often lost their power or become unreliable for direct usage. Here we derive fundamental limitations on how effectively generic noisy resources can be purified enforced by the laws of quantum mechanics, which universally apply to any reasonable kind of quantum resource. Remarkably, it is impossible to achieve perfect resource purification, even probabilistically. Our theorems indicate strong limits on the efficiency of distillation, a widely-used type of resource purification routine that underpins many key applications of quantum information science. In particular, we present explicit lower bounds on the resource cost of magic state distillation, a leading scheme for realizing scalable fault-tolerant quantum computation