Imaging stars with quantum error correction

—by Zixin Huang

EQUS researchers have proposed a quantum error-correction protocol that corrects for loss and noise when imaging stars and thus enhances imaging resolution.

The performance of an imaging system is limited by diffraction, which means that the resolution is constrained by the size of the system's light collectors and the wavelength of the source radiation.  For astronomy, the holy grail would be optical interferometers roughly the size of Earth.  However, the development of large optical interferometers is hindered by loss, noise and the physical weight of the instrument.

The EQUS team have proposed a general, experimentally feasible protocol for storing star light in widely separated quantum memories, which can then be measured to determine the location and intensity distribution of the source.  To mimic a large optical interferometer, the light must be collected and processed coherently.  We propose to use quantum error correction to mitigate errors due to loss and noise in this process.

Quantum error correction is a rapidly developing area, focused mainly on enabling scalable quantum computing in the presence of errors.  Our proposal applies quantum error correction to an imaging task where the signal has not been prepared by the experimenter.  Our scheme represents an application for near-term, intermediate-scale quantum devices that may increase imaging resolution beyond what is feasible using classical techniques.

By using STIRAP (stimulated Raman adiabatic passage), we developed a general quantum code for coupling an arbitrary string to the starlight, despite the light--matter interaction Hamiltonian being fixed.  We showed that even a small code offers substantial protection against noise during imaging.

Our work has implications for the quantum and astronomy communities because it lays the foundation for developing the next generation of quantum-enabled optical telescopes.  An optical interferometer the size of Earth's diameter would be powerful enough to image small planets around nearby stars, details of solar systems, kinematics of stellar surfaces, and potentially details around black-hole event horizons, none of which can be resolved by currently planned projects.

We're now developing the framework into multi-mode networks, and working with experimentalists (include EQUS Deputy Director Thomas Volz) to perform a proof-of-principle demonstration.

Read the full paper here: https://arxiv.org/abs/2204.06044.  Zixin is an Associate Investigator based at Macquarie University.  This work fits into EQUS' Quantum-Enabled Diagnostics and Imaging research program.