# Quantum Signal Processing

Motivated by the rapid development of quantum computers in recent years and the increasing interest in quantum technologies, also the field of quantum sensing emerged. The goal of this latter research area is to utilize quantum physical effects in the field of sensor technology and sensing techniques and to develop concepts in order to achieve a higher accuracy of the measured quantity compared to classical approaches and to open up new fields of application.

The term "quantum radar" (QR) refers to a measurement principle in the RF and mmWave range which is also known as "quantum illumination" in the optical regime. QR achieves a higher detection probability with the aid of entangled photon pairs. First, an entangled pair of microwave photons is generated. One of them, the idler photon, is retained, whereas the other one, the signal photon, is emitted into the environment. Similar to the classical radar principle the signal may be collected after scattering by an object with a receiving antenna. The reflected signal exhibits a correlation with the retained idler photon which exceeds in strength the correlation that would be possible classically.

In our research we are interested in the theoretical description of quantum physical effects related to quantum illumination, the pertaining signal processing from an engineering perspective, and the identification of new application areas in the ultra low power domain. The foundations of our activities are based on classical signal processing and operator theory as well as network theoretic modeling of quantum circuit components.