The quantum world is by far larger than the classical one. It is entanglement, closely linked to non-locality, that spans this larger space manifold. Entanglement plays a central role in emerging quantum technology aiming to harvest quantum space. From the experimentalist’s point of view working in nanoelectronics, there is no instrument on the shelf yet, that would measure the degree of entanglement. This we would like to change with QUEST.

QUEST is a long term project with the goal to experimentally establish a continuous probe of entangle­ment generation in the electrical signal of quantum devices. It is set up in two parts: the realization of a highly efficient source of spin-entangled electron pairs and the exploration of different correlation measurements providing a measure of entanglement “on the fly”.  During the last decade a wealth of theory proposals have appeared, addressing entanglement in electronic devices. The interaction of parti­cles in solid-state devices provides a natural force for the appearance of entanglement. Examples are correlation between electrons and holes in the emission on a tunnel junction, or the “naturally” occurring Cooper pairs in s-wave superconductors. While first results on the realization of sources of entangled electron pairs have appeared recently, there are no experiments demonstrating entanglement in trans­port of any of those devices. We aim to change this and propose to implement high-bandwidth current correlation methods up to the forth moment, enabling to test Bell-inequality and quantum state tomo­graphy. Based on our long standing experience in the measurement of second-order correlations in nano devices, we are well prepared for this very challenging goal.