Quantum Measurement and Manipulation Group

In the qM&M group at IFA we focus on the investigation of basic quantum physical phenomena. We are interested in the theoretical description and experimental realization of the transition from simple, fundamental systems like single or few atoms in very well controlled potentials (such as particle in a box) – representing text-book like simplicity – to well controlled complex systems consisting of hundreds of atoms suited for the implementation of quantum technologies such as quantum computers and quantum simulators. The power in these systems lies in the fact that the Hilbert space is so enormous that it is impossible for classical computers to perform a full simulation of the dynamics. With this we hope to develop new powerful computers as well as a simulator to investigate fundamental quantum problems in other fields of physics. One long term goal of this field will be to design new quantum materials with tailored properties, such as high Tc superconductors at room temperature.

 The main concepts to realize this are:

  • Optical lattices: artificial crystals of light created by interfering laser beams in which atoms are attracted to each lattice site characterized by constructive interference of the light. Atoms hopping in this lattice can be used to mimick the motion of electrons in solid state systems. In addition, atoms can be organized in an ultra-cold cystaline structure with only one atom per lattice site. This can form the main computing core of a large scale quantum computer.
  • Arbitrary potential energy landscape: Using a modified beamer/projector (Digital Mirror Device, DMD) arbitrary patterns of light can be created and reconfigured dynamically. This can create ultra-focused tweezers of light to move around atoms, or custom such as square-wells or rings.
  • Non-destructive measurements: Measurements are some of the most interesting phenomena in quantum mechanics, because it has such a dramatic effect to the quantum state. We are interested in experimentally and theoretically investigating this effect of measurements on ultra-cold atoms and explore how this can be used to create resources (such as entanglement) for quantum technologies as well as modifying the fundamental properties of quantum materials. The dream is to use continuous measurements on a cloud of atoms to  change quantum phase diagrams in order to make desired new properties as accessible as possible.
  • Numerical optimization: for quantum technologies it is crucial to perform operations as quickly as possible. In quantum physics there is a fundamental limit on the speed of quantum operations, the Quantum Speed Limit, based on the time-energy uncertainty relation. The question is, how can we find these fastest possible transformations? To do this, we study state-of-the-art computer optimization algorithms from computer science such as multi-agent optimization, genetic algorithms, and general machine learning (artificial intelligence) and apply it to quantum problems.
  • Quantum games: we have found that state-of-the-art optimization algorithms fails for certain classes of quantum problems related to quantum computer. We have therefore developed online quantum games in which players use their intuition to solve these.  First games have been successful and we are currently expanding to other quantum challenges and in addition try to learn from the players to develop new artificial intelligence optimization algorithms.
  • Game-based education: In the longer run, we have the vision of engaging and educating the public to the extent that they can become active scientific collaborators and assist not only in the solution of research challenges but also in the formulation of new ones. This development of a Citizen Science V2.0, is of course a huge, long-term undertaking. We start this in small steps by developing educational games and through interventions in primary, secondary, high-school, as well as university test the effectiveness of the learning activities.

See more here.