Macroscopic Quantum Resonators Path Finder (MAQRO-PF) White Paper

TL;DR

This white paper proposes MAQRO-PF, a space-based pathfinder to push the quantum-classical boundary for macroscopic objects using levitated optomechanics in LEO. By employing a floating optical bench and a standing-wave optical grating, the mission aims to achieve drag-free quantum-coherent evolution for objects with masses far larger than atoms, targeting at least $10~\text{s}$ of coherence under $10^{-9}$ g conditions. The document details design concepts, ongoing developmental efforts (loading, autonomous control, and pulsed gratings), and concrete current-best-estimate requirements (vibration, rotation, pointing, thermal stability, and data handling). If successful, MAQRO-PF would validate space-based approaches to large-m mass quantum experiments, inform a future Earth–Sun L2 MAQRO mission, and align with national science strategy and international collaborations. The work also highlights potential spin-offs in quantum sensing, fundamental physics tests, and technology development for future quantum-enabled spacecraft.

Abstract

Optically levitated particles are used in a wide range of experiments to explore both fundamental physics and to act as sensors to a variety of external forces. One field of particular interest that these particles can be used to investigate is quantum mechanics. Previous research has yet to set an absolute upper bound on the size of objects that can be prepared in a quantum superposition. Exploring this limit involves allowing ever-larger objects to freely and coherently evolve to assess if their behaviour matches quantum or classical theoretical predictions. However, the long free evolution times required for these behaviours to be visible result in the experiments being gravitationally limited. Space based platforms therefore become the next key step in these investigations. In this white paper, we shall discuss our proposal for an optical levitation experiment in space that will explore the fundamental upper size limits of quantum mechanics. We shall cover the scientific motivation behind these investigations, then summarize the current status of our designs for the satellite. We will then review the aspects of the payload that require further development, then summarize the current estimates of the payload's requirements.

Figures (3)

• Figure 1: [Right] The Op-to-Space payload being integrated into [Left] The Exploration Company's Nyx 'Mission Possible' capsule.
• Figure 2: Process of conducting matterwave interferometry in space belenchia2021test.
• Figure 3: Diagram of the design concept for the floating optical bench.