Quantum Matter and Optics
The quantum nature of matter and light has grown into a broad and fruitful research field for theorists and experimentalists alike. It combines foundational research with toward applications, the most well known of which is the quantum computer.
Macroscopic Quantum Systems
One line of research addresses the macroscopic limit of quantum mechanics: how large can an object be and still preserve a quantum entangled state? For that study, we have developed opto-mechanical samples with vibration-isolated cryogenics that allow us to perform measurements on the quantum properties of the system in the regime of large masses.
Quantum entanglement in itself is also a subject of research, with evidence accumulating that forms of matter exist wich are entangled on the macroscopic scale. This field benefits from theoretical advances in quantu information, and especially the holographic (AdS/CFT) duality discovered in string theory. Closely related is research into topological materials.
Quantum Optics and Plasma
Quantum information research strongly rely on the quantum nature of light and the interaction of single photons with single solid-state quantum systems. This research line joins solid-state quantum optics with micro-cavities, high-dimensional multi-photon entanglement, single photon detection and superconductivity.
Also a number of related research topics are investigated, such as research on topology in optics and plasma physics where knotted and linked forms of plasma are investigated that are expected to have exceptional stability, or the application of silver nano-clusters in medicine.
Following the 2012 discovery by our experimental colleagues in Delft of Majorana fermions, we developed a method to use these charge-neutral quasiparticles as qubits in a quantum computer. This hybrid approach is now being implemented in Delft, as well as in competing laboratories, to perform the first braiding operation – which is the ‘holy grail’ of the field.
These quantum systems can often only be investigated using advanced microscopy techniques. Leiden specializes in techniques that combine microscopy with spectroscopy, such as charge transport spectroscopy, molecular fluorescence spectroscopy, STM spectroscopy and and LEEM spectroscopy.