Learning unknown pure quantum statesopen access
- Authors
- Lee, Sang Min; Lee, Jin hyoung; Bang, Jeongho
- Issue Date
- Nov-2018
- Publisher
- AMER PHYSICAL SOC
- Citation
- PHYSICAL REVIEW A, v.98, no.5, pp.1 - 8
- Indexed
- SCIE
SCOPUS
- Journal Title
- PHYSICAL REVIEW A
- Volume
- 98
- Number
- 5
- Start Page
- 1
- End Page
- 8
- URI
- https://scholarworks.bwise.kr/hanyang/handle/2021.sw.hanyang/149062
- DOI
- 10.1103/PhysRevA.98.052302
- ISSN
- 2469-9926
- Abstract
- We propose a learning method for estimating unknown pure quantum states. The basic idea of our method is to learn a unitary operation (U) over cap that transforms a given unknown state vertical bar psi(tau)> to a known fiducial state vertical bar f >. Then, after completion of the learning process, we can estimate and reproduce vertical bar psi(tau)> based on the learned (U) over cap (a) under bar nd vertical bar f >. To realize this idea, we cast a random-based learning algorithm, called "single-shot measurement learning," in which the learning rule is based on an intuitive and reasonable criterion: the greater the number of success (or failure), the less (or more) changes are imposed. Remarkably, the learning process occurs by means of a single-shot measurement outcome. We demonstrate that our method works effectively, i.e., the learning is completed with a finite number, say N, of unknown-state copies. Most surprisingly, our method allows the maximum statistical accuracy to be achieved for large N, namely similar or equal to O (N-1) scales of average infidelity. It highlights a nontrivial message, that is, a random-based strategy can potentially be as accurate as other standard statistical approaches.
- Files in This Item
-
- Appears in
Collections - 서울 자연과학대학 > 서울 물리학과 > 1. Journal Articles
![qrcode](https://api.qrserver.com/v1/create-qr-code/?size=55x55&data=https://scholarworks.bwise.kr/hanyang/handle/2021.sw.hanyang/149062)
Items in ScholarWorks are protected by copyright, with all rights reserved, unless otherwise indicated.