liquid_spacetime

The ‘liquid’ nature of spacetime in quantum gravity models

An illustration of the liquid spacetime concept. Credit: Jason Ralston/Flickr
Se lo spaziotempo fosse un liquido, avrebbe una viscosità bassissima, come i “superfluidi“. Un lavoro che ha visto collaborare la Scuola Internazionale Superiore di Studi Avanzati (SISSA) di Trieste con l’Università Ludwig Maximilian di Monaco ha mostrato come dovrebbero comportarsi gli “atomi” che compongono il fluido dello spaziotempo, secondo alcuni modelli di gravità quantistica. Le considerazioni proposte in questo lavoro impongono vincoli molto stretti al verificarsi di effetti legati a questa eventuale natura “fluida” dello spaziotempo, mostrando che è possibile discriminare tra i modelli di gravità quantistica finora sviluppati al fine di superare la Relatività Generale.

In this theoretical framework, it has been suggested that spacetime should be treated as a fluid. In this sense, general relativity would be the analogue to fluid hydrodynamics, which describes the behaviour of fluids at a macroscopic level but tells us nothing about the atoms/molecules that compose them. Likewise, according to some models, general relativity says nothing about the “atoms” that make up spacetime but describes the dynamics of spacetime as if it were a “classical” object. Spacetime would therefore be a phenomenon “emerging” from more fundamental constituents, just as water is what we perceive of the mass of H2O molecules that form it. Stefano Liberati, professor at the International School for Advanced Studies (SISSA) in Trieste, and Luca Maccione, a research scientist at the Ludwig-Maximilian University in Munich, have devised innovative ways of using the tolls of elementary particle physics and high energy astrophysics to describe the effects that should be observed if spacetime were a fluid. Liberati and Maccione also proposed the first observational tests of these phenomena.

SISSA: Liquid spacetime: A very slippery superfluid, that's what spacetime could be like
arXiv: Astrophysical constraints on Planck scale dissipative phenomena
SciAm: If Spacetime Were a Superfluid, Would It Unify Physics—or Is the Theory All Wet?