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Quantum physics with electrical circuits

Dr. Daniel Esteve, Quantronics School, CEA-Saclay, France

17 May 2013 11:00


Solid state  electrical circuits that  behave as  artificial quantum atoms  are now fabricated  for processing quantum information, and  for addressing  fundamental issues in quantum mechanics.  I will describe how a simple  superconducting artificial atom, the Cooper pair box, embedded in a microwave cavity just as atoms are in cavity QED physics, provides a playground for quantum mechanics and an operational quantum bit. In this talk, I will give an overview of superconducting qubit circuits, and will discuss some quantum physics experiments.

In a single qubit circuit measured and driven at the same time, we have demonstrated  the violation of the Leggett and Garg inequality  which falsifies the assumptions of macrorealism, considered as plausible for macroscopic systems such as electrical circuits. With  an elementary quantum processor, we have demonstrated the quantum speed-up expected from quantum computing in the simple case of the Grover search algorithm. By coupling an ensemble of microscopic electronic spins and a qubit and to a same microwave cavity, we have demonstrated the operation of a quantum memory based on spin ensembles.


Prof. Dr. Stefan Blügel
Phone: +49 2461 61-4249
Fax: +49 2461 61-2850
email: s.bluegel@fz-juelich.de