A communication network that can be used to teleport quantum information between continents - that is the ambitious aim of Professor Arno Rauschenbeutel's research at the Institute of Atomic and Subatomic Physics at TU Wien. He uses fibre-optic cables to link atoms and light and is thus developing the crucial building blocks for quantum communication technologies of the future. This work is now being funded by an ERC Consolidator Grant awarded by the European Research Council.
Ultra-thin glass fibres
The glass fibres used in experiments conducted by Arno Rauschenbeutel's research group are barely five hundred nanometres thick - less than the wavelength of the light being channelled through them. The light wave therefore does not pass completely through the fibre; some of it projects outwards. "It is precisely in this area just outside of the fibre, where another electromagnetic field can be detected, that we can link atoms to the light," explains Rauschenbeutel.
This enables highly efficient linking to be achieved between materials and light - just what is needed to produce quantum mechanical entanglement. When two objects are entangled in a quantum physical sense, perhaps two photons or one photon and one atom, their states are more strongly correlated than we can explain with conventional everyday logic. This entanglement plays a key role for future quantum communication networks or quantum computers.
Storage and quantum information processing
"To enable the use of quantum information one day in our own everyday work, we first need three key elements," says Rauschenbeutel. "One source for photons with exactly the right properties, one quantum storage repository, which can be used to reliably store the information, and a non-linear interaction, that entangles photons with each other." Work on these three objectives can now be continued at TU Wien within the scope of the ERC project.
If two light waves overlap in free space, they don't have any influence on each other - therefore, no quantum physical entanglement can arise between them. For light to interact with other light, special optical materials are required. This normally only functions at very high light intensities. However, in quantum experiments, we are specifically interested in low light intensity - perhaps for the entanglement of just two photons.
Glass fibres with coupled atoms are ideal for that very purpose. "If you choose light with a wavelength that is precisely matched to the atoms used, you can create powerful non-linear interactions that would have to allow two individual photons to become entangled with each other," says Arno Rauschenbeutel. He now wants to use the ERC funding to create and investigate these entanglements.
Arno Rauschenbeutel has studied in Düsseldorf, London and Bonn, he wrote his doctoral thesis at the Ecole normale supérieure in Paris. As an assistant, he returned to Bonn to begin with, before becoming a professor at the University of Mainz. At the end of 2010, Arno Rauschenbeutel was finally appointed to the Institute of Atomic and Subatomic Physics at TU Wien. His research group is part of the joint university initiative known as the Vienna Centre for Quantum Science and Technology (VCQ). His ERC Consolidator Grant is endowed with two million euros over a period of five years.
Prof. Arno Rauschenbeutel in Portrait, opens an external URL in a new window
Prof. Arno Rauschenbeutel
Atomic and Subatomic Physics
Vienna Center for Quantum Science and Technology
Stadionallee 2, 1020 Vienna
Phone: +43 1 58801 141761
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