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Updated: May 18, 2026
07:56
A Photonic System for Generating Unconditional Polarization-Entangled Photons Based on Multiple Quantum Interference
Published on: September 5, 2019
Quantum discord bounds the amount of distributed entanglement
T K Chuan1, J Maillard, K Modi
1Centre for Quantum Technologies, National University of Singapore, Singapore.
Physical Review Letters
|September 26, 2012
Summary
Quantum entanglement distribution can be enhanced using quantum communication carriers, even unentangled ones. This study bounds entanglement increase by nonclassical correlations, offering new insights into quantum information protocols.
Area of Science:
- Quantum Information Science
- Quantum Communication
- Quantum Entanglement
Background:
- Distributing quantum entanglement is crucial for quantum theory tests and quantum information protocols.
- Entanglement can be amplified between distant parties via quantum communication carriers.
- Entanglement cannot increase under classical communication, necessitating a quantum carrier.
Purpose of the Study:
- To investigate the theoretical limits of increasing entanglement between two parties using a quantum carrier.
- To establish a general bound for entanglement increase based on the carrier's nonclassical correlations.
- To explore new methods for entanglement distribution using unentangled states.
Main Methods:
- Quantification of nonclassical correlations in the carrier using the relative entropy of discord.
- Derivation of a bound relating entanglement increase (relative entropy of entanglement) to carrier discord.
- Analysis of implications and examples of entanglement distribution via unentangled states.
Main Results:
- The increase in relative entropy of entanglement is generally bounded by the relative entropy of discord of the carrier.
- Demonstrated that entanglement can be distributed even when the carrier is not itself entangled.
- Established new limitations on the phenomenon of entanglement enhancement in quantum communication.
Conclusions:
- Nonclassical correlations in the carrier, not necessarily entanglement, are key to enhancing distributed entanglement.
- The derived bound provides a fundamental understanding of entanglement distribution limits.
- Findings advance the development of quantum communication protocols and fundamental quantum tests.
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