Quantum-enabled optical large-baseline interferometry: applications, protocols and feasibility

Optical Very Long Baseline Interferometry (VLBI) offers the potential for unprecedented angular resolution in astronomical imaging and geodetic measurements. However, classical implementations face fundamental challenges, including photon loss, atmospheric turbulence, the requirements for dynamical delay lines, and the quantum nature of light. This review surveys recent proposals in quantum-enabled VLBI, which seeks to overcome these limitations through entanglement-assisted interferometry, quantum memory storage, and nonlocal measurement techniques. We highlight some key applications, including direct imaging of exoplanets, precision tracking of stellar orbits near black holes, and geodetic monitoring of Earth’s rotation and the Moon’s librations. Particular attention is given to quantum-enhanced telescope architectures, including repeater-based long-baseline interferometry and quantum error-corrected encoding schemes, which offer a pathway toward high-fidelity optical VLBI. By integrating quantum technologies, future interferometric networks may achieve diffraction-limited imaging at optical and near-infrared wavelengths, surpassing the constraints of classical techniques and enabling new precision tests of astrophysical and fundamental physics phenomena.