Fase (stof)

For alternative betydninger, se Fase. (Se også artikler, som begynder med Fase)

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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:

• Plasmaform
• Gasform
• Flydende form
• Fast form

Mindre kendte faser omfatter stoffers diamagnetiske, paramagnetiske og ferromagnetiske faser.

Her er en liste over nogle af de videnskabeligt anerkendte stoffaser:

• Plasma (ioniseret gas)
• Gasform, "luftformigt"
• Flydende form
• Superflydende fast stof^{[1][2][3][4][5]}
• Fast form
• Bose-Einstein kondensat
• Fermionisk kondensat^[6][7][8]

Her udover spekuleres der i yderligere tilstandsformer/faser:

• "polariton superfluid"^[9]
• "Bosonmetal"^[10]
• "Nukleonagtig stof" – En neutronstjernes massefylde antages at være tæt på atomkerners og neutroners.^[11]
• "Kvarkagtig stof" – En kvarkstjernes massefylde antages at være højere end neutronstjerners og dermed atomkerners og neutroners.^[11]

1. ^ "2 September 2004, physicsweb: Evidence for supersolid is firmed up". Arkiveret fra originalen 11. december 2004. Hentet 19. december 2004.
2. ^ 2005-05-18, sciencedaily: Supersolids -- Can Atoms Unify And Flow Without Resistance? Arkiveret 20. maj 2005 hos Wayback Machine Citat: "...Chan points out, the behavior of any atom can be described both as a particle and as a wave-packet...When the supercooled helium atoms expanded out into one another, he continues, they lost their individuality and became one giant atom..."
3. ^ 2004-01-15, ScienceDaily: Probable Discovery Of A New, Supersolid, Phase Of Matter Arkiveret 5. februar 2015 hos Wayback Machine Citat: "...We apparently have observed, for the first time, a solid material with the characteristics of a superfluid...but because all its particles are in the identical quantum state, it remains a solid even though its component particles are continually flowing..."
4. ^ 2 September 2004, physicsweb: Evidence for supersolid is firmed up Arkiveret 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."..."
5. ^ 14 January 2004, physicsweb: Supersolid is seen in the lab Arkiveret 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)..."
6. ^ 29 January, 2004, BBC News: New form of matter created in lab Arkiveret 11. april 2004 hos Wayback Machine Citat: "...The new matter is the sixth known form of matter after solids, liquids, gasses, plasma and a Bose-Einstein condensate..."
7. ^ "2004-01-29, Sciencedaily: NIST/University Of Colorado Scientists Create New Form Of Matter: A Fermionic Condensate". Arkiveret fra originalen 6. januar 2015. Hentet 29. januar 2004.
8. ^ Number 671 #1, January 30, 2004, AIP: Halfway Across the BEC-BCS Prairie Arkiveret 11. februar 2004 hos Wayback Machine Citat: "...describes the new NIST state as "a dramatic new sort of fermionic condensate, basically Cooper pairing in the strong-field limit."..."
9. ^ May 18, 2007, Science Daily: Scientists test new form of matter Arkiveret 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...."
10. ^ "Science Daily, 2003-10-10: Metallic Phase For Bosons Implies New State Of Matter". Arkiveret fra originalen 5. februar 2015. Hentet 11. oktober 2003.
11. ^ ^{a b} Ing.dk: Ny form for materiale fundet i universet (Webside ikke længere tilgængelig) Citat: "...Astronomerne tror, at det måske skyldes, at disse stjerner er sammensat af rene kvark-partikler, eller at de indeholder krystaller fra sub-nukleare partikler..."