Arbitrary state preparation in quantum harmonic oscillators using neural networks

TL;DR

This paper introduces a neural network-based method for preparing arbitrary quantum states in harmonic oscillators by controlling coupled qubits and oscillators with pulse sequences, achieving high fidelities.

Contribution

It presents a novel neural network approach to determine pulse sequences for state preparation in quantum harmonic oscillators, enabling high-fidelity creation of qubit and qutrit states.

Findings

Achieved 99.9% fidelity for qubit state preparation.

Achieved 97.0% fidelity for qutrit state preparation.

Demonstrated effective neural network prediction of pulse parameters.

Abstract

Preparing quantum states is a fundamental task in various quantum algorithms. In particular, state preparation in quantum harmonic oscillators (HOs) is crucial for the creation of qudits and the implementation of high-dimensional algorithms. In this work, we develop a methodology for preparing quantum states in HOs. The HO is coupled to an auxiliary qubit to ensure that any state can be prepared in the oscillator [J. Math. Phys. 59, 072101]. By applying a sequence of square pulses to both the qubit and the HO, we drive the system from an initial state to a target state. To determine the required pulses, we use a neural network that predicts the pulse parameters needed for state preparation. Specifically, we present results for preparing qubit and qutrit states in the HO, achieving average fidelities of 99.9% and 97.0%, respectively.