### Abstract

The possibility of detecting correlations between two quantum-mechanical systems from only the information of a subsystem is investigated. For generic cases, we prove that there exist correlations between two quantum systems if the time derivative of the reduced purity is not zero. Therefore, an experimentalist can conclude that correlations between the system and some environment are nonzero if the time derivative of the reduced purity is found not to be zero. A quantitative estimation of the time derivative of the reduced purity with respect to correlations is also given. This clarifies the role of correlations in the mechanism of decoherence in open quantum systems.

Original language | English |
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Article number | 042123 |

Journal | Physical Review A - Atomic, Molecular, and Optical Physics |

Volume | 76 |

Issue number | 4 |

DOIs | |

Publication status | Published - 2007 Oct 23 |

Externally published | Yes |

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### ASJC Scopus subject areas

- Atomic and Molecular Physics, and Optics
- Physics and Astronomy(all)

### Cite this

*Physical Review A - Atomic, Molecular, and Optical Physics*,

*76*(4), [042123]. https://doi.org/10.1103/PhysRevA.76.042123

**How to detect a possible correlation from the information of a subsystem in quantum-mechanical systems.** / Kimura, Gen; Ohno, Hiromichi; Hayashi, Hiroyuki.

Research output: Contribution to journal › Article

*Physical Review A - Atomic, Molecular, and Optical Physics*, vol. 76, no. 4, 042123. https://doi.org/10.1103/PhysRevA.76.042123

}

TY - JOUR

T1 - How to detect a possible correlation from the information of a subsystem in quantum-mechanical systems

AU - Kimura, Gen

AU - Ohno, Hiromichi

AU - Hayashi, Hiroyuki

PY - 2007/10/23

Y1 - 2007/10/23

N2 - The possibility of detecting correlations between two quantum-mechanical systems from only the information of a subsystem is investigated. For generic cases, we prove that there exist correlations between two quantum systems if the time derivative of the reduced purity is not zero. Therefore, an experimentalist can conclude that correlations between the system and some environment are nonzero if the time derivative of the reduced purity is found not to be zero. A quantitative estimation of the time derivative of the reduced purity with respect to correlations is also given. This clarifies the role of correlations in the mechanism of decoherence in open quantum systems.

AB - The possibility of detecting correlations between two quantum-mechanical systems from only the information of a subsystem is investigated. For generic cases, we prove that there exist correlations between two quantum systems if the time derivative of the reduced purity is not zero. Therefore, an experimentalist can conclude that correlations between the system and some environment are nonzero if the time derivative of the reduced purity is found not to be zero. A quantitative estimation of the time derivative of the reduced purity with respect to correlations is also given. This clarifies the role of correlations in the mechanism of decoherence in open quantum systems.

UR - http://www.scopus.com/inward/record.url?scp=35549005000&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=35549005000&partnerID=8YFLogxK

U2 - 10.1103/PhysRevA.76.042123

DO - 10.1103/PhysRevA.76.042123

M3 - Article

VL - 76

JO - Physical Review A

JF - Physical Review A

SN - 2469-9926

IS - 4

M1 - 042123

ER -