Clever Design, Unexpected Obstacles: Insights on Implementing a Quantum Boltzmann Machine

TL;DR

This paper reports on the implementation challenges of a quantum Boltzmann machine, highlighting limitations of current quantum algorithms and software, and assessing the feasibility on existing NISQ hardware.

Contribution

It systematically analyzes implementation obstacles of a quantum Boltzmann machine and discusses their implications for future quantum algorithm development.

Findings

Identified structural limitations of the quantum algorithm

Highlighted software development kit constraints

Assessed feasibility on current NISQ devices

Abstract

We have implemented a gated-based quantum version of a restricted Boltzmann machine for approximating the ground state of a Pauli-decomposed qubit Hamiltonian. During the implementation and evaluation, we have noticed a variety of unexpected topics. It starts from limitations due to the structure of the algorithm itself and continues with constraints induced by specific quantum software development kits, which did not (yet) support necessary features for an efficient implementation. In this paper we systematically summarize our findings and categorize them according to their relevance for the implementation of similar quantum algorithms. We also discuss the feasibility of executing such implementations on current NISQ devices.