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arXiv · 1704.06469

Coherence, Asymmetry, and Quantum Macroscopicity

Hyukjoon Kwon·Chae-Yeun Park·Kok Chuan Tan·Daekun Ahn·Hyunseok Jeong
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Abstract

We investigate a measure of quantum coherence and its extension to quantify quantum macroscopicity. The coherence measure can also quantify the asymmetry of a quantum state with respect to a given group transformation. We then show that a weighted sum of asymmetry in each mode can be applied as a measure of macroscopic coherence. To exclude the effects of microscopic superpositions, we suggest a method to introduce a cutoff to the weighted sum that will specify the macroscopic portion of the coherence. This cutoff may be interpreted as the fuzziness for a given measurement outcome. Based on the suggested measures, we investigate the quantum macroscopicity for particular concrete examples in N-partite spin systems.

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Hyukjoon Kwon, Chae-Yeun Park, Kok Chuan Tan, Daekun Ahn, Hyunseok Jeong. 2017-04-21. Coherence, Asymmetry, and Quantum Macroscopicity. https://doi.org/10.1103/physreva.97.012326

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