Nanofizika  - Nanophysics


ERC Starting Independent 
         Researcher Grant



Cooper pairs as a source of entanglement




Principal Investigator (PI): Dr. Szabolcs Csonka

Duration in months: 60

Starting: 2010. november

Funding: 1 496 000 Euró



Entanglement and non-locality are spectacular fundamentals of quantum mechanics and basic resources of future quantum computation algorithms. Electronic entanglement has attracted increasing attention during the last years. The electron spin as a purely quantum mechanical two level system has been put forward as a promising candidate for storing quantum information in solid state. Recently, great progress has been achieved in manipulation and read-out of quantum dotbased spin Qubits. However, electron spin is also suitable to transfer quantum information, since mobile electrons can be coherently transmitted in a solid state device preserving the spin information. Thus, electron spin could provide a general platform for on-chip quantum computation and information processing.


Although several theoretical concepts have been worked out to address spin entangled mobile electrons, the absence of an entangler device has not allowed their realization so far. The aim of the present proposal is to overcome this experimental challenge and explore the entanglement of spatially separated electron pairs. Superconductors provide a natural source of entanglement, because their ground-state is composed of Cooper pairs in a spin-singlet state. However, the splitting of the Cooper pairs into separate electrons has to be enforced, which has been very recently realized by the applicant in two quantum dot Y-junction.


This Y-junction will be used as a central building block to split Cooper pairs in a controlled fashion and the non-local nature of spin and charge correlations will be addressed in various device configurations. Our research will go well beyond the state-of-the-art, it will give access to the fundamentals of Cooper pair splitting, explore novel two particle interference processes and target electronic quantum teleportation.


This research project will lead to a profound understanding of the production, manipulation and detection of spin entangled mobile electron pairs, thus it will significantly extend the frontiers of quantum coherence and opens a new horizon in the field of on-chip quantum information technologies.