Quantum Register of Fermion Pairs

Thomas Hartke | Botond Oreg | Ningyuan Jia | Martin Zwierlein

Quantum control of motion is central for modern atomic clocks and interferometers, it enables protocols to process and distribute quantum information, and allows probing entanglement in correlated states of matter. However, motional coherence of individual particles can be fragile to maintain, as external degrees of freedom couple strongly to the environment. Here we demonstrate long-lived motional coherence and entanglement of pairs of fermionic atoms in an optical lattice array. The common and relative motion of each pair realize a robust qubit, protected by exchange symmetry. The energy difference between the two motional states is set by the atomic recoil energy, only dependent on mass and lattice wavelength, and insensitive against noise of the confining potential. We observe quantum coherence beyond ten seconds. Modulating interactions between the atoms provides universal control of the motional qubit. The methods presented here open the door towards coherently programmable quantum simulators of many-fermion systems, precision metrology based on atom pairs and molecules, and digital quantum computation employing fermion pairs.

Funding Sources: NSF through the Center for Ultracold Atoms and Grant PHY-2012110, ONR (Grant No. N00014-17-1-2257) | AFOSR (Grant No. FA9550-16-1-0324) | AFOSR-MURIs on Quantum Phases of Matter (Grant No. FA9550-14- 1-0035) and on Molecular Ensembles | Gordon and Betty Moore Foundation through grant GBMF5279 | Vannevar Bush Faculty Fellowship