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A Photonic System for Generating Unconditional Polarization-Entangled Photons Based on Multiple Quantum Interference
Published on: September 5, 2019
Distinguishing arbitrary multipartite basis unambiguously using local operations and classical communication.
Runyao Duan1, Yuan Feng, Zhengfeng Ji
1State Key Laboratory of Intelligent Technology and Systems, Department of Computer Science and Technology, Tsinghua University, Beijing, China, 100084. dry@tsinghua.edu.cn
Physical Review Letters
|August 7, 2007
Summary
Multipartite quantum states have a minimum number of distinguishable states, even with limited local operations and classical communication (LOCC). This finding reveals a stronger "nonlocality without entanglement" and guarantees a locally distinguishable entangled basis.
Area of Science:
- Quantum Information Theory
- Quantum Many-Body Systems
- Foundations of Quantum Mechanics
Background:
- Understanding the distinguishability of quantum states is crucial for quantum information processing.
- Local Operations and Classical Communication (LOCC) represent the most fundamental form of information processing available to distant parties in a quantum system.
- Previous research has explored the limits of distinguishability in multipartite quantum systems, but a definitive lower bound and its implications remained elusive.
Purpose of the Study:
- To establish a rigorous lower bound on the number of unambiguously distinguishable states in any basis of a multipartite quantum state space.
- To demonstrate the optimality of this lower bound through explicit construction.
- To explore the connection between this bound and the phenomenon of "nonlocality without entanglement" and the existence of locally distinguishable entangled bases.
Main Methods:
- Derivation of a general lower bound for the number of LOCC-distinguishable states in a multipartite system.
- Analytical construction of a specific product basis to demonstrate the optimality of the derived bound.
- Investigation of the implications of this construction for nonlocality without entanglement and entangled bases.
Main Results:
- An arbitrary basis for a K-party multipartite quantum state space, with local dimensions dk, contains at least N = Σ(k=1 to K) (dk-1)+1 members unambiguously distinguishable by LOCC.
- This lower bound N is shown to be optimal.
- A special product basis with exactly N LOCC-distinguishable members is analytically constructed.
Conclusions:
- A fundamental limit exists on the number of quantum states that can be distinguished locally across multiple parties.
- The constructed optimal basis provides a stronger manifestation of "nonlocality without entanglement."
- The existence of such a basis implies the existence of a locally distinguishable entangled basis, deepening our understanding of quantum correlations.
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