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QLEDS project on proton / antiproton quantum logic manipulation funded by ERC starting grant "QLEDS" with 1.6 million EUR.

QLEDS project on proton / antiproton quantum logic manipulation funded by ERC starting grant "QLEDS" with 1.6 million EUR.

The QLEDS project aims to apply ion-trap quantum logic techniques to precision measurements on individual (anti-)protons for fundamental physics tests. In particular, we aim to measure g-factors of single (anti-)protons as a precise test of CPT symmetry. This requires a method to detect single (anti-)proton spin flips. Current efforts based on classical “magnetic bottle” techniques are hurt by the extreme difficulty and slowness of the spin state detection. Discrete and direct state measurement is a prerequisite for inaccuracies below 10-6 and has not been achieved yet.

Towards this end, we will employ a radically different approach and use quantum logic techniques developed by the PI in the NIST ion storage group of D. J. Wineland. This will allow us to transfer the (anti-)proton’s spin state to a nearby trapped atomic “logic” ion and subsequently read it out using standard quantum logic detection techniques along the lines of Heinzen and Wineland. The same ideas are also at the root of NIST’s world-record single-ion Al+ frequency standard.

Ultimately, this quantum logic technique will lead to a precise test of CPT symmetry, a fundamental symmetry within the standard model of particle physics, by comparing the proton’s and the antiproton’s g-factor with fast detection and single spin-flip resolution. It thus has the potential to reach inaccuracies below 10-9, exceeding the state-of-the-art for the antiproton g-factor by six orders of magnitude. Such a measurement is urgently needed to complement ongoing tests with electrons and positrons. It is closely intertwined with our desire to understand the observed matter-antimatter imbalance in the universe and to obtain a unified description of matter and interactions. Further, the project will considerably broaden the arsenal of quantum state manipulation techniques in Penning traps and possibly impact high precision mass measurement.

Author: jm