sINGle microwave photon dEtection for hybrid quaNtum Information prOcessing and quantUm enhanced Sensing

Introduction

The wave/particle duality is one of the counter-intuitive traits of quantum mechanics. The fundamental constituents of matter and light can be either apprehended as corpuscles or waves depending on the choice of the measurement apparatus.

Measurement Modalities

In the case of light, one can either decide to measure the quadrature of the electromagnetic field or count the photons impacting the detector. These two modalities come with pros and cons:

1. The first method is sensitive to both the phase and the amplitude of the field but at the cost of a fundamental noise associated with vacuum fluctuations.
2. The latter method is only sensitive to the energy of the field.

Importance of Photons

Photons lie at the heart of the human experience; they are the most direct way to sense our immediate material environment. A light source irradiates material objects in its surroundings, and depending on their composition, materials will re-emit the incident light with slight variations in intensity and color.

Advances in Imaging

In the course of the last century, the meaning of imaging has been considerably broadened. Scientific and technological advances have enabled the detection of single quanta of light from further away, at smaller scales, and across a considerable portion of the electromagnetic spectrum.

Microwave Quantum Optics

At one extremity of the spectrum, the field of microwave quantum optics (1-10 GHz) has emerged as a powerful tool to probe quantum systems. We have recently demonstrated high-performance single microwave photon detection based on elementary superconducting circuits.

Proposal Overview

Based on this novel method, a new window on new material systems is opened at unprecedented sensitivities. This proposal aims at the improvement of the newly developed single microwave photon detector for the exploration of new luminescent systems in the microwave domain.

Specific Applications

In particular, the focus will be on:

• The detection of individual paramagnetic electron spins for quantum computing and quantum-enhanced sensing applications.
• The search for one of the leading dark-matter candidates, axions.