Converting nonclassicality to quantum correlations via beamsplitters

¹ School of Mathematics and Physics, University of Science and Technology Beijing - Beijing 100083, China
² Academy of Mathematics and Systems Science, Chinese Academy of Sciences - Beijing 100190, China
³ School of Mathematical Sciences, University of Chinese Academy of Sciences - Beijing 100049, China

Received: 3 September 2019
Accepted: 6 November 2019

Abstract

While for single-mode bosonic fields, one talks about nonclassicality of quantum states, which plays an important role in various quantum information processing tasks, for composite systems, one talks about quantum correlations such as quantum entanglement and quantum discord, which are crucial and indispensable for implementation of quantum communication and computation. Both nonclassicality and quantum correlations are quantum features of physical systems and fundamental resources which can be exploited to bring supremacy over classical systems. A natural question arises on the relation and interconversion between these two resources. In this work, we investigate the conversion of single-mode nonclassicality into quantum correlations via beamsplitters. Our work is based on the idea of Asbó et al. (Phys. Rev. Lett., 94 (2005) 173602) of converting nonclassicality into quantum entanglement via a balanced beamsplitter. Through a paradigmatic setup with Gaussian states fed into the beamsplitters, we demonstrate that quantum correlations between the output states, as exhibited by either entanglement or quantum discord, increase monotonically with nonclassicality of the input Gaussian states, as quantified by an information-theoretic measure in terms of the Wigner-Yanase skew information.