Programming an Optical Lattice Interferometer

TL;DR

This paper develops quantum logic gates for a cold atom optical lattice interferometer, enabling programmable control of atomic momentum for enhanced inertial sensing, using quantum optimal control techniques.

Contribution

It introduces a set of quantum logic gates tailored for optical lattice interferometers, expanding programmable quantum sensing beyond confined qubits.

Findings

Derived quantum gates manipulating atomic momentum states.

Applied quantum optimal control to design lattice modulation waveforms.

Demonstrated potential for improved inertial sensing applications.

Abstract

Programming a quantum device describes the usage of quantum logic gates, agnostic of hardware specifics, to perform a sequence of operations with (typically) a computing or sensing task in mind. Such programs have been executed on digital quantum computers, which despite their noisy character, have shown the ability to optimize metrological functions, for example in the generation of spin squeezing and optimization of quantum Fisher information for signals manifesting as spin rotations in a quantum register. However, the qubits of these programmable quantum sensors are tightly spatially confined and therefore suboptimal for enclosing the kinds of large spacetime areas required for performing inertial sensing. In this work, we derive a set of quantum logic gates for a cold atom optical lattice interferometer that manipulates the momentum of atoms. Here, the operations are framed in terms of single qubit operations and mappings between qubit subspaces with internal levels given by the Bloch (crystal) eigenstates of the lattice. We describe how the quantum optimal control method of direct collocation is well suited for obtaining the modulation waveforms of the lattice which achieve these operations.