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Extracting entanglement from identical particles
N Killoran1, M Cramer1, M B Plenio1
1Institut für Theoretische Physik, Albert-Einstein-Allee 11, Universität Ulm, D-89069 Ulm, Germany.
Physical Review Letters
|May 3, 2014
Summary
Entanglement in identical particles, even when condensed, can be extracted into independent modes for quantum information tasks. This reveals fundamental connections between entanglement, squeezing, and indistinguishability.
Area of Science:
- Quantum mechanics
- Quantum information theory
- Condensed matter physics
Background:
- Identical particles and entanglement are core quantum mechanics concepts.
- Standard entanglement measures fail for identical particles in single modes.
- This limitation has historically reduced perceived value for quantum information tasks.
Purpose of the Study:
- To demonstrate that entanglement in identical particles is a valuable resource.
- To show entanglement can be extracted from identical particles for practical applications.
- To resolve debates on the quantum resource capabilities of condensed identical particle systems.
Main Methods:
- Formal analysis of entanglement in systems of identical particles.
- Developing a method to extract entanglement into independent modes.
- Establishing a one-to-one correspondence between mode entanglement and particle entanglement.
Main Results:
- Any entanglement among identical particles, including symmetrization-induced entanglement, can be extracted into an entangled state of independent modes.
- The entanglement of the mode system directly corresponds to the entanglement between inaccessible identical particles.
- New insights into entanglement generation in passive optical networks.
Conclusions:
- Systems of identical particles possess valuable, extractable entanglement for quantum information.
- The study settles long-standing debates regarding the resource capabilities of such states, like spin-squeezed Bose-Einstein condensates.
- Reveals fundamental links between entanglement, squeezing, and particle indistinguishability.
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