Applications of quantum coherence and quantum correlation in optics

Michael Berry

Dan Lei, Disheng Guo, Jun Xin +1 more

Attenuation and amplification are the most common processes for optical communications. Amplification can be used to compensate the attenuation of the complex amplitude of an optical field, but is unable to recover the coherence lost, provided that the attenuation channel and the amplification channel are independent. In this paper, we show that the quantum coherence of an optical field can be regained if the attenuation channel and the amplification channel share correlated noise. We propose an all-optical correlated noisy channel relying on the four-wave mixing process and demonstrate its capability of recovering quantum coherence within continuous-variable systems. We quantitatively investigate the coherence recovery phenomena for coherent states and two-mode squeezed states. Moreover, we analyze the effect of other photon losses that are independent from the recovery channel on the performance of recovering coherence. Different from correlated noisy channels previously proposed based on electro-optic conversions, the correlated noisy channel in our protocol is all-optical and thus owns larger operational bandwidths.

Ming‐Liang Hu, Xueyuan Hu, Yi Peng +2 more

Quantum coherence and quantum correlations are of fundamental and practical significance for the development of quantum mechanics.They are also cornerstones of quantum computation and quantum communication theory. Searching physically meaningful and mathematically rigorous quantifiers of them are long-standing concerns of the community of quantum information science, and various faithful measures have been introduced so far. We review in this paper the measures of discordlike quantum correlations for bipartite and multipartite systems, the measures of quantum coherence for any single quantum system, and their relationship in different settings. Our aim is to provide a full review about the resource theory of quantum coherence, including its application in many-body systems, and the discordlike quantum correlations which were defined based on the various distance measures of states. We discuss the interrelations between quantum coherence and quantum correlations established in an operational way, and the fundamental characteristics of quantum coherence such as their complementarity under different basis sets, their duality with path information of an interference experiment, their distillation and dilution under different operations, and some new viewpoints of the superiority of the quantum algorithms from the perspective of quantum coherence. Additionally, we review properties of geometric quantum correlations and quantum coherence under noisy quantum channels. Finally, the main progresses for the study of quantum correlations and quantum coherence in the relativistic settings are reviewed. All these results provide an overview for the conceptual implications and basic connections of quantum coherence, quantum correlations, and their potential applications in various related subjects of physics.

Chang-shui Yu, Yang Zhang, Haiqing Zhao

Daniel F. Walls, Gerard J Milburn

Takayoshi Kobayashi

This book highlights the physical processes of quantum mechanics, such as quantum interference, entanglement, and quantum teleportation, within the topic of quantum information and quantum computing.Quantal and Classical Coherence and Correlation begins with exploring the general mathematical and physical concepts of coherence and correlation and provides a comparative discussion of classical and quantum coherence and correlation. In this context, the author explains the principles of quantum information, and the discussion then moves to material coherence and optical coherence and their control. He then discusses the differences between classical and quantal information techniques. The book closes with a discussion on the application probabilities of quantum technologies by examining the present and future applications of coherence. This book is intended for upper‑level undergraduate and graduate physics and engineering students who are studying nonlinear optics, light–matter interaction, and quantum information; and industrial professionals who are involved in electronics and photonics. It will also be of interest to engineers who are involved in quantum information and quantum networks.