Quantum Information Processing with Complex Media

The world’s most advanced quantum technologies rely for a large part on the control and manipulation of quantum states of light. From entanglement swapping to Boson sampling, linear optical devices such as beam splitters and integrated photonic circuits are essential for accomplishing key tasks in quantum communication and computation.

Scaling up from proof-of-principle demonstrations in the lab remains a challenge: approaches based on both bulk and integrated optics require precise control over every element involved and are normally limited to a planar (2D) architecture. Thus, as the demands of a quantum information protocol increase, the experimental complexity required to achieve it rapidly becomes prohibitive.

In the QuompleX project, we propose an alternative approach for the control and manipulation of quantum states of light. Recent years have seen the development of techniques that allow unprecedented control over classical light propagation through complex scattering media. Such media are analogous to a complex network of optical elements, control over which has led to exciting new possibilities for biomedical imaging and classical communication. Here, we aim to harness the transformative potential of complex media for quantum information processing. By carefully controlling the scattering process for multiple photons, we will use complex media as multimode linear optical networks for generating, manipulating, and transporting complex quantum states of light.

Our specific objectives are as follows: 1) Theoretically evaluate the class of general high-dimensional unitary transformations that can be performed with common complex media such as multi-mode fibres and multiple scattering media, 2) apply these transformations for the transport and control of high-dimensional quantum states of light in complex media, 3) develop multiport linear optical devices in complex media for the generation of high-dimensional multi-photon entanglement, and 4) demonstrate multi-level, semi-device-independent quantum communication protocols in complex media and implement noise-resistant tests of quantum mechanics with the tools developed above.

The consortium members at the QuompleX kickoff event in Vienna

The consortium members at the QuompleX kickoff event in Vienna.


  • Coordinator: Mehul Malik (Institute for Quantum Optics and Quantum Information, Vienna, AT)
  • Claudio Conti (CNR National Research Council, IT)
  • Pepijn Pinkse (University of Twente, NL)