Gaussian quantum information

TLDR

Quantum information science emerged over two decades, centering on manipulating qubits and giving rise to quantum computers, cryptography, and teleportation, while continuous‑variable carriers provide a powerful alternative with analytical tools and readily available optical components. The review surveys continuous‑variable quantum information processes based on Gaussian states, operations, and measurements, covering theoretical foundations, landmark experiments, and recent advances. It examines how Gaussian states, operations, and measurements underpin tasks such as communication, cryptography, computation, teleportation, and state discrimination, and discusses the associated theoretical tools and experimental realizations. Gaussian quantum information enables a broad range of applications—communication, cryptography, computation, teleportation, and state discrimination—thanks to its analytical tractability and experimental accessibility.

Abstract

The science of quantum information has arisen over the last two decades centered on the manipulation of individual quanta of information, known as quantum bits or qubits. Quantum computers, quantum cryptography, and quantum teleportation are among the most celebrated ideas that have emerged from this new field. It was realized later on that using continuous-variable quantum information carriers, instead of qubits, constitutes an extremely powerful alternative approach to quantum information processing. This review focuses on continuous-variable quantum information processes that rely on any combination of Gaussian states, Gaussian operations, and Gaussian measurements. Interestingly, such a restriction to the Gaussian realm comes with various benefits, since on the theoretical side, simple analytical tools are available and, on the experimental side, optical components effecting Gaussian processes are readily available in the laboratory. Yet, Gaussian quantum information processing opens the way to a wide variety of tasks and applications, including quantum communication, quantum cryptography, quantum computation, quantum teleportation, and quantum state and channel discrimination. This review reports on the state of the art in this field, ranging from the basic theoretical tools and landmark experimental realizations to the most recent successful developments.