Furtive quantum sensing using matter-wave cloaks

We introduce the concept of furtive quantum sensing, demonstrating the possibility of concealing quantum objects from matter waves while maintaining their ability to interact and to get excited by the impinging particles. This is obtained by cloaking, with tailored homogeneous metamaterial layers, quantum systems having internal degrees of freedom. The effect is a low-observable quantum sensor with drastically reduced elastic scattering and optimized absorption levels, a concept that opens interesting venues in particle detection, high-efficiency electrical pumping, and quantum information processing.