Crystallization of strongly interacting photons in a nonlinear optical fibre. D. E. Chang, V. Gritsev, G. Morigi, V. Vuletic, M. D. Lukin and E. A. Demler in Nature Phys. 4:884 (2008).  What the paper says?

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This paper discusses Lieb-Liniger and Tonks-Girardeau physics with what the Authors call "optical photons", based on the EIT Rydberg blockade mechanism. Although this is in space, their focus is on eventual temporal correlations:

«a quantum light field can undergo fermionization in such one-dimensional media, which can be probed via standard photon correlation measurements.»

This is of special interest to us viz our photon liquefaction, to which it seems to map directly:

«This system would correspond to nonlinear quantum optics in its extreme, in which individual photons behave as impenetrable particles. In this limit, an optical pulse separates into non-overlapping wave packets of individual photons, and a ‘crystal of photons’ ensues.
During this stage, any spatial correlations that formed in the polaritons while evolving under the NLSE are directly mapped into temporal correlations (at a common point in space) of purely outgoing photons, which can be measured using standard quantum optical techniques.

although they speak of "crystals", their description is really similar to the one we made that refers to a liquid:

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They also give us a name for the oscillations: Friedel oscillations.[1]


  1. Metallic alloys. J. Friedel in Il Nuovo Cimento 7:287 (1958).