1. Purification of Gaussian States by Photon Subtraction
- Author
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Zhang, Kun, Li, Huijun, Jing, Jietai, Treps, Nicolas, and Walschaers, Mattia
- Subjects
Quantum Physics ,Physics - Optics - Abstract
Photon subtraction can enhance entanglement, which for pure states induces a decrease in the purity of reduced states. In contrast, by analyzing the purities of Gaussian states before and after subtracting a single photon, we prove that the purity of a Gaussian state can also be increased by less than 20%. On the one hand, it reveals that photon subtraction can reduce entanglement, and on the other hand, it reveals that it can achieve a limited amount of Gaussian state purification. Through the analysis of some examples, we demonstrate the inherent mechanism and applicable scope of photon-subtraction-based purification. In a multimode system, we find that photon subtraction can increase entanglement and purify some of the reduced states simultaneously. We thus present purification through the suppression of Gaussian noise as a new application for photon subtraction in continuous-variable quantum information processing., Comment: 7 pages, 3 figures, comments welcome!
- Published
- 2024