Quan­tum Net­wor­king

Research in quantum networking is addressing the development of applicable concepts in quantum information processing and quantum computing. The main research activities are on ultrashort pulse quantum optics and its application, quantum simulation and quantum walks, generation  of specifically engineered (higher-dimensional) quantum states, and quantum state and process tomography using photon number resolved detection. A further new activity is on integrated continuous variable quantum optics.

The quantum walk model describes the coherent propagation of quantum particles in discrete environments. This versatile concept allows to explain the complex dynamics of quantum particles in physical, chemical and biological systems. Additionally, quantum walks provide a new and promising framework for quantum computation applications. Our group focuses on implementing quantum walks in different optical architectures ranging from fiber-based experiments to integrated wave guide arrays.

Ultrafast light pulses are currently subject to a flourishing field of research activities. They offer, for instance, the fascinating opportunity to study dynamic processes at very short timescales and promise the future multiplication of bit rates in optical communication systems. Over the last years, a highly sophisticated toolbox has been developed to realise ever shorter pulses, with specifically engineered temporal and spectral properties. On the other hand, making use of the quantum features of light has paved the way towards novel quantum communication and information applications.

Quantum states of light show characteristics beyond the classical properties of the electromagnetic field. In particular, non-classical states such as single photon Fock states or entangled states can be seen as resources for many quantum information tasks. In our group, we use photon number resolving measurements. These enable us to generate, on the one hand, highly non-lassical states and, on the other hand, offer promising new methods for quantum state characterization.

KTP waveguide chip

Continuous-variable quantum optics is a relatively unexplored field in integrated quantum optics. A small number of experiments have shown the production of quantum states in such devices, but further operations or the production of more advanced states on-chip have not yet been demonstrated. The expertise and facilities available at Paderborn University provide a platform for advancing this field by producing continuous-variable states of high strength and purity.

Integrated devices provide a phase-stable platform for the interaction and manipulation of one or multiple quantum states by…