In a study published in the journal Nature, the researchers showed that liquid crystals can be used to produce so-called entangled photons. This is a quantum state of light where a pair of photons (the fundamental particles of light) always act as an inseparable whole, meaning they cannot be described separately. They are interconnected in such a way that measuring the state of one immediately influences the state of the other, regardless of the distance between them. Besides the phenomenological interest, these sources represent a tool for the realization of quantum technologies.

In addition to the efficiency of generating entangled photons in liquid crystals being comparable to the best existing sources, their main advantage lies in the fact that the quantum state of the photon pair can be tunably altered. This can be achieved by applying an electric field or by arranging the molecules of the liquid crystal into the appropriate configuration. With the ability to tunably change the quantum state, the presented results indicate exceptional practical potential for numerous quantum technologies, such as quantum communication, quantum computing, and quantum metrology.

A summary of the research can also be viewed in the presentation video.

Source:

Sultanov, V., Kavčič, A., Kokkinakis, E. et al. Tunable entangled photon-pair generation in a liquid crystal. Nature (2024). https://doi.org/10.1038/s41586-024-07543-5

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