Dynamics of Doped Quantum Magnets

Name of applicant

Kristian Knakkergaard Nielsen


Max Planck Institute of Quantum Optics, Garching bei München, Germany


DKK 972,610



Type of grant

Internationalisation Fellowships


My project seeks to develop new theoretical tools and methods to describe doped quantum magnets. These systems are formed by removing a few particles from a magnetically ordered lattice. The resulting vacant sites - or holes - effectively move around the lattice, disturbing the magnetic environment, and leading to a highly correlated motion. State-of-the-art experiments allow us to physically model such complex systems by trapping atoms in so-called optical lattices. This makes it possible to study these systems in great detail - atom by atom. Importantly, the physics of doped quantum magnets is known to be intimately linked with high-temperature superconductivity. These fascinating materials suddenly let electric current travel without loss below a certain critical temperature.


Superconductors are already used for MRI diagnostics, the particle accelerators at CERN, and the high-speed Maglev trains. However, most superconductors need to be cooled to about -270ºC by liquid helium, which is becoming increasingly scarce and expensive. High-temperature superconductors can potentially circumvent these obstacles. However, their fundamental properties remain a mystery, preventing us from developing more resilient and flexible materials. At the same time, doped quantum magnets is also an important example of strongly interacting quantum many-body systems out of equilibrium. In particular, the presence of holes in the lattice leads to the formation of quasi-particles called magnetic polarons that could well provide the effective charges carrying the super-current.


The research will be conducted at the Max Planck Institute Of Quantum Optics (MPQ) in Garching bei München, Germany. They are one of the world-leading institutions in quantum science, performing groundbreaking experiments with optical lattices and continuing to redefine the state of the art of cold-atom quantum simulations. At the same time, their Theory Division has pioneered many of the core concepts and applications of quantum computation, quantum simulation, and quantum many-body physics, that have become a foundation for modern quantum science and technology. The MPQ will, thus, be the ideal place to pursue the described project and greatly broaden my research scope.

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