Denne artikel bør gennemlæses af en person med fagkendskab for at sikre den faglige korrekthed.
I fysikvidenskaberne er en fase eller stoffase tilstanden af det makroskopiske fysiske system, som har nogenlunde ens kemisk sammensætning og fysiske egenskaber (f.eks. massefylde, krystalstruktur, brydningsindeks...). De mest kendte faseeksempler (tidligere tilstandsformer) er:
^2 September 2004, physicsweb: Evidence for supersolid is firmed upArkiveret 11. december 2004 hos Wayback Machine Citat: "...However, many of the details of the experiment are not yet understood. In an accompanying article Tony Leggett of the University of Illinois in Urbana writes that the experiment "will force theorists to revise dramatically the generally accepted picture of crystalline solid helium-4."..."
^14 January 2004, physicsweb: Supersolid is seen in the labArkiveret 11. december 2004 hos Wayback Machine Citat: "...Eun-Seong Kim and Moses Chan of Pennsylvania State University say their supersolid behaves like a superfluid – a liquid that flows without resistance – but has all the characteristics of a crystalline solid (E Kim and M H W Chan 2004 Nature 427 225)..."
^May 18, 2007, Science Daily: Scientists test new form of matterArkiveret 27. september 2007 hos Wayback MachineCitat: "...In the new state of matter -- called a polariton superfluid -- the wave behavior leads to a pure light beam similar to that from a laser but is much more energy efficient...He said it may be demonstrated at room temperature in the near future...."