Simple quantum states of light

Shaul Mukamel, Matthias Freyberger, Wolfgang P. Schleich +31 more

Abstract Conventional spectroscopy uses classical light to detect matter properties through the variation of its response with frequencies or time delays. Quantum light opens up new avenues for spectroscopy by utilizing parameters of the quantum state of light as novel control knobs and through the variation of photon statistics by coupling to matter. This Roadmap article focuses on using quantum light as a powerful sensing and spectroscopic tool to reveal novel information about complex molecules that is not accessible by classical light. It aims at bridging the quantum optics and spectroscopy communities which normally have opposite goals: manipulating complex light states with simple matter e.g. qubits versus studying complex molecules with simple classical light, respectively. Articles cover advances in the generation and manipulation of state-of-the-art quantum light sources along with applications to sensing, spectroscopy, imaging and interferometry.

Akira Furusawa

Akira Furusawa

Arnab Chatterjee, Subrata Sarkar, Shreyas Changder +1 more

Abstract In recent years, multiple low light image enhancement algorithms have been developed, using both conventional techniques and machine learning based approaches. These techniques work as post processing methods, which add additional computational overhead. In this paper, a quantum image representation model has been proposed for low light images based on the Improved Simple Quantum Representation (ISQR). It is inspired by the Simple Quantum Representation (SQR) algorithm, which was originally designed for infrared imaging. ISQR extends its applicability by efficiently encoding low light grayscale and color images on quantum computing platforms As quantum imaging hardware is not yet commercially available, all experiments in this study were conducted through simulations to validate the proposed approach. ISQR is proposed as a quantum image representation technique in which classical pixel values are encoded into a quantum state , and an enhanced image is obtained after multiple quantum measurement and classical reconstruction. The enhancement performance of the proposed model is compared through multiple classical low light image enhancement algorithms and statistical analysis. In this paper, the coal mine and surveillance examples are shown primarily as qualitative case studies to demonstrate how ISQR behaves in extremely low light conditions. All these analyses and advantages highlight its potential for future quantum camera development.

Rafael F. Barros, G. B. Alves, Olivier Pfister +1 more

Quantum optical cluster states have been increasingly explored in the light of their importance for measurement-based quantum computing. Here we set forth a method for generating quantum controlled cluster states: pumping an optical parametric oscillator with spatially structured light. We show that state-of-the-art techniques for producing clusters in the spectral and temporal domains are improved by a structured light pump, which manipulates the spatial mode couplings in the parametric interaction. We illustrate the method considering a second-order pump structure and show that a simple mode rotation yields different cluster states, including but not limited to the two-dimensional square and hexagonal lattices. We also introduce a novel technique for generating nonuniform cluster states and propose a simple setup for its implementation.