Quantum computation toolbox for decoherence-free qubits using multi-band alkali atoms

Abstract

We introduce protocols for designing and manipulating qubits with ultracold alkali atoms in 3D optical lattices. These qubits are formed from two-atom spin superposition states that create a decoherence-free subspace immune to stray magnetic fields, dramatically improving coherence times while still enjoying the single-site addressability and Feshbach resonance control of state-of-the-art alkali atom systems. Our protocol requires no continuous driving or spin-dependent potentials, and instead relies upon the population of a higher motional band to realize naturally tunable in-site exchange and cross-site superexchange interactions. As a proof-of-principle example of their utility for entanglement generation for quantum computation, we show the cross-site superexchange interactions can be used to engineer 1D cluster states. Explicit protocols for experimental preparation and manipulation of the qubits are also discussed, as well as methods for measuring more complex quantities such as out-of-time-ordered correlation functions (OTOCs).

10+7 pages, 6+1 figures. Advanced Quantum Technologies (2020)

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Cited by in corpus (5)

• Quantum Register of Fermion Pairs
• Observation of unitary p-wave interactions between fermions in an optical lattice
• Robust nuclear spin entanglement via dipolar interactions in polar molecules
• Spin Entanglement and Magnetic Competition via Long-range Interactions in Spinor Quantum Optical Lattices
• Emergent $s$-wave interactions in orbitally active quasi-two-dimensional Fermi gases