Superfluid qubit systems with ring shaped optical lattices

TL;DR

This paper proposes a novel qubit system using neutral atomic currents in ring-shaped optical lattices, combining low decoherence and topological robustness, with experimental realization of scalable ring-lattice potentials.

Contribution

It introduces a new neutral atom-based qubit implementation using ring-shaped optical lattices with tunable interactions and demonstrates experimental feasibility for scalable quantum registers.

Findings

Successfully realized scaled ring-lattice potentials for multiple qubits

Proposed protocols for qubit initialization, addressing, and read-out

Demonstrated potential for scalable quantum computing with neutral atoms

Abstract

We study an experimentally feasible qubit system employing neutral atomic currents. Our system is based on bosonic cold atoms trapped in ring-shaped optical lattice potentials. The lattice makes the system strictly one dimensional and it provides the infrastructure to realize a tunable ring-ring interaction. Our implementation combines the low decoherence rates of of neutral cold atoms systems, overcoming single site addressing, with the robustness of topologically protected solid state Josephson flux qubits. Characteristic fluctuations in the magnetic fields affecting Josephson junction based flux qubits are expected to be minimized employing neutral atoms as flux carriers. By breaking the Galilean invariance we demonstrate how atomic currents through the lattice provide a implementation of a qubit. This is realized either by artificially creating a phase slip in a single ring, or by tunnel coupling of two homogeneous ring lattices. The single qubit infrastructure is experimentally investigated with tailored optical potentials. Indeed, we have experimentally realized scaled ring-lattice potentials that could host, in principle, $n\sim 10$ of such ring-qubits, arranged in a stack configuration, along the laser beam propagation axis. An experimentally viable scheme of the two-ring-qubit is discussed, as well. Based on our analysis, we provide protocols to initialize, address, and read-out the qubit.