Hypergraph states and quantum advantage

• Applicant: Ismaël Septembre
• Subject Area: Optics, Quantum Optics and Physics of Atoms, Molecules and Plasmas
• Term: since 2026
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 572827488

The understanding of quantum mechanics in the 20th century brought our society to a new era: the information era. The first quantum revolution has indeed led to the development of modern computers, that is, it has forged our lives the way they are. However, it did not exploit the most peculiar features of quantum mechanics, such as superpositions of states (Schrödinger’s cat) or entanglement. This is at the heart of the ongoing second quantum revolution. In this context, the study of quantum information is crucial. Quantum computers can nowadays outperform classical computers, has demonstrated recently, and the paradigm of information is about to shift from fully classical to a cohabitation of classical and quantum information. Modern cryptography may become obsolete, while at the same time, the speed-up of calculations provided by quantum computers will lead to major advances in all fields of science. In this project, I, Ismaël Septembre, will perform cutting-edge research on multi-partite entanglement at the University of Siegen under the supervision of Otfried Gühne. I will investigate how hypergraph states (a category of quantum states that can be addressed on a photonic chip) can be used to demonstrate quantum advantage. Their entanglement properties are promising but not yet fully understood. I will study which hypergraph states hold more resources for quantum computations. I will design protocols to certify the topology of hypergraph states and the entanglement structure of a quantum network. Finally, I will find the optimal hypergraph states that cannot be simulated on a classical computer. My project will considerably advance the current knowledge on the entanglement properties of hypergraph states and find exciting applications in quantum computing in the long term.

• DFG Programme: Position