If you interconnect telescopes in huge networks, you encounter problems with image sharpness that classical physics cannot solve. But by taking advantage of the quantum properties of starlight, astronomers may be able to circumvent these limitations.
Thanks to quantum computers that can detect and correct their own errors, we may be able to build planet-sized telescopes. This allows astronomers to overcome the limitations of current telescopes and to clearly visualize distant objects in space.
Astronomers trying to capture images of distant stars and planets must do so with the little light reaching their telescopes. They can increase resolution by interconnecting telescopes in what is then called an “astronomical interferometer.” However, to get sharp images of the most distant objects we know, those networks would have to span thousands of kilometers. At this scale, image sharpening techniques based on classical physics no longer work.
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The dance of the giants
Quantum physicist Zixin Huang from Macquarie University in Australia and her colleagues have now discovered that large interferometers using quantum methods be able to process light, effectively entering one photon at a time† This technique can also sharpen blurred images. The approach relies on a technique that was originally developed for communication between quantum computers.
Quantum hard drive
Astronomers can often ignore the ‘quantum nature’ of light, but when so little light reaches the telescope, the particles no longer behave in the classical way, quantum physicist says Daniel Gottesman from the University of Maryland in the United States, who was not involved in the research project. ‘That means that this light is really quantum, you just can’t ignore that,’ he says.
When light particles from stars enter the telescopes, you could record them on a sort of quantum version of a hard disk, made up of specially prepared atoms. The specific energy and arrival time of the photons cause different atoms to end up in different states.
The light from a single star reaching the interferometer is quantum mechanically entangled. This allows the separate telescopes to act as one large telescope without losing data through the data transfer normally required to create an image.
Gigantic resolution
To then process that information, scientists could use error-correction quantum computers, which are programmed to detect and correct errors during calculations. If you don’t use this type of computer, the process is vulnerable to glitches and errors that affect the final image.
Huang’s team is the first to propose the use of error-correcting quantum computers in astronomy. Their analysis shows that it is possible to produce sharp images even when more than 10 percent of the starlight data is affected by interference.
Thanks to quantum mechanics, a giant telescope could have a resolution thousands of times higher than any existing or planned interferometer.
Obstacles
†This is an example of an application of quantum technology for which there simply is no classical counterpart’, says quantum physicist Emil Khabibouline from Harvard University in the US. “It allows you to get around classic limitations.”
Many of the parts needed to build a telescope with the new system have already been tested separately. There are just a few obstacles. For example, you must ensure that it is not too expensive for distant, interconnected telescopes to exchange quantum information. “There are many more challenges to tackle before we actually have a planet-sized device, but this is a good first step,” says Huang.
A similar approach can be used to look further into space and discover previously inaccessible details. Huang is already studying how to improve our understanding of signals emanating from water or hydrogen on planets outside the solar system — potential indicators of life.