2016 Fiscal Year Annual Research Report
Entanglement and nonlocality in quantum theory
| Project/Area Number |
16F16769
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| Research Institution | The University of Tokyo |
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Principal Investigator |
村尾 美緒 東京大学, 大学院理学系研究科(理学部), 教授 (30322671)
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| Co-Investigator(Kenkyū-buntansha) |
COELHO QUINTINO MARCO TULIO 東京大学, 理学(系)研究科(研究院), 外国人特別研究員
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| Project Period (FY) |
2016-11-07 – 2019-03-31
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| Keywords | 量子非局所性 / エンタングルメント / 高階量子演算 |
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| Outline of Annual Research Achievements |
Quantum nonlocality not only has deep implications to the foundations of quantum mechanics but it can also be used to certify quantum properties (e.g., quantum entanglement and measurement incompatibility) and information protocols (e.g., cryptography and random number generation). Although quantum entanglement is required for nonlocality, these two concepts are not equivalent, and their connection is still not well understood. The firs year’s target is to understand the connection between entanglement and nonlocality by studying super-activation protocols based in quantum networks and local pre-processing.
In this first 4 months we have focused in finishing projects that have started in Geneva but strongly related to this proposal. We have discussed the research plan on activation of quantum nonlocality in the many copies/network regime. One project got published (Better local hidden variable models for two-qubit Werner states and an upper bound on the Grothendieck constant KG(3)) and another paper was finished and sent for publication (Most incompatible measurements for robust steering tests).
We have also started a new direction of the project on higher order quantum operations. In particular, we consider a situation that a physicist has access to some restricted copies of an unknown quantum reversible operation (hence, a unitary channel) and wants to be able to implement the inverse of this operation. We find protocols that can be used to succeed on this task and identity some scenarios where this task cannot be accomplished.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
本研究を開始する前にジュネーブ大学において着手した、状態の複製がある場合の量子非局所性に関する研究を本研究計画と関連して発展させることができ、論文を出版することができた。また、受け入れ研究者の研究グループが行なってきた研究内容を深く理解することができ、高階量子演算(higher order quantum operation)の視点を取り入れた、新しいアプローチによる量子非局所性の解析可能性を見出すことができた。これは研究計画時には予想していなかった新しい方向性での発展である。
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| Strategy for Future Research Activity |
The plan for next year is to understand higher order quantum operation and how one can implement operations that have no definite causal order in quantum mechanics. In order to succeed, we are going to consider probabilistic scenarios and scenarios where some extra, but finite, uses of the operations we want to implement without a definite causal order. We are also going to continue seeking for examples of activation of quantum nonlocality to understand better the relation between quantum entanglement and nonlocal correlations.
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