4 ms·

Light gas compresses easily because photons are bosons. Most ordinary matter is fermionic.

• yccs27 5y ago
  Some atoms also behave as bosons (specifically those consisting of an even number of elementary fermions), so that cannot be the real difference.
  • gus_massa 5y ago
    IIUC the effect in bosons was already known, and the new interesting part is that they were able to measure it in a photon gas experimentally: From the abstract of the paper: > For gases of material particles, studies of the mechanical response are well established, in fields from classical thermodynamics to cold atomic quantum gases. [i.e. a similar result is known for atoms] > Here we demonstrate a measurement of the compressibility of a two-dimensional quantum gas of light in a box potential and obtain the equation of state for the optical medium. The experiment is carried out in a nanostructured dye-filled optical microcavity. [i.e. this is a new experimental result] > We observe signatures of Bose-Einstein condensation at high phase-space densities in the finite-size system. [i.e. the photons are bosons as expected] Just in case, this is not a dismissive comment. I'd like to add that it's amazing and weird that they can measure this.
    • yccs27 5y ago
      Oh wow, thank you for the clarification! If I understand it correctly then, the divergent compressibility is a consequence of Bose-Einstein condensation? It definitely is exciting to see light show this effect. I wonder how much the difference between light and matter (due to very different dispersion relations) has an influence on the BEC properties like compressibility. I guess that's what they are trying to find out.
  • wrycoder 5y ago
    Except for electron degeneracy pressure.
  • deleted 5y ago
    [deleted]