Virtuel partikel

	Kvantemekanik
Baggrund
	Bra-ket notation • Gammel kvanteteori • Hamilton-funktion • Interferens • Klassisk mekanik
Grundlæggende koncepter
	Atommodel • Bølgefunktion • CPT-teoremet • Bølgefunktionens kollaps • Ikke-lokalitet • Komplementaritet • Dekohærens • Kohærens • Måling • Sammenfiltring • Spin • Superposition • Tunnelering • Kvantespring • Kvanteteleportation • Kvantetilstand • Partikel-bølge-dualitet • Partikel i en boks • Paulis udelukkelsesprincip • Symmetri i kvantemekanik • Ubestemthed • Virtuel partikel
Eksperimenter
	Bells tests • Bose-Einstein-kondensat • Dobbeltspalte • Frank-Hertz • Kvante Hall-effekten • Mach-Zehnder • Stern–Gerlach
Formuleringer
	Born-Oppenheimer • Hartree-Fock • Heisenberg • Interaktion • Kurve-integraler • Matrix-mekanik • Relativistisk kvantemekanik • Schrödinger
Ligninger
	Dirac • Klein–Gordon • Pauli • Rydberg • Schrödinger
Fortolkninger
	• Københavnerfortolkningen • de Broglie–Bohm • Skjulte variabler • Mange-verdens • Schrödingers kat
Avancerede emner
	Dc-squid • Degenereret stof • Josephson-kontakt • Kvantecomputer • Kvanteelektrodynamik • Kvantefeltteori • Kvantekaos • Kvantekemi • Kvantekromodynamik • Kvanteoptik • Kvante-statistisk mekanik • Kvante-informationsteori • Kvanteø • Kvasipartikel • Rapid single flux quantum • Resonanstunneldiode • Resonanstunneltransistor • Single electron transistor • Spredningsteori • Tunneldiode • Tæthedsmatrix
Videnskabsmænd
	Bell • Bogoljubov • Bohm • Bohr • Born • Bose • de Broglie • Compton • Dirac • Debye • Ehrenfest • Einstein • Everett • Fock • Fermi • Feynman • Heisenberg • Hilbert • Jordan • Kramers • von Neumann • Pauli • Lamb • Laue • Planck • Raman • Rydberg • Schrödinger • Sommerfeld • Weyl • Wigner • Zeeman • Zeilinger
	v; d; r;

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En virtuel partikel, eller mere præcist en virtuel kvantemekanisk partikel, er en kvantemekanisk partikel, der opstår tilsyneladende "ud af ingenting" og eksisterer i et ekstremt kort tidsrum. Årsagen hertil ligger i Heisenbergs usikkerhedsprincip: Da partiklens "position" i tiden kun kan ligge indenfor det ganske korte tidsrum den eksisterer, er usikkerheden omkring energimængden tilsvarende stor – tilpas stor til, at der kan være energi nok til at skabe en partikel.

For eksempel er de udvekslingspartikler, der formidler den stærke kernekraft, (som er ansvarlig for at holde sammen på atomkerner,) virtuelle partikler: De eksisterer lige akkurat længe nok til at vandre fra én nukleon (proton eller neutron) i atomkernen til den næste, og skaber derved bindingen imellem nukleonerne.

Virtuelle partikler dukker op overalt, inkl. i vakuum. Man kan godt omdanne virtuelle partikler til "almindelige" kvantemekaniske partikler.^[1] Måske kan fx kvantemekaniske antipartikler, som indgår i antistof, laves økonomisk på denne måde.

Kilder/referencer

^ Nov 17, 2011, phys.org: Scientists create light from vacuum Citat: "... Scientists at Chalmers University of Technology have succeeded in creating light [ fotonpartikler ] from vacuum – observing an effect first predicted over 40 years ago...In fact, the vacuum is full of various particles that are continuously fluctuating in and out of existence. They appear, exist for a brief moment and then disappear again. Since their existence is so fleeting, they are usually referred to as virtual particles... By changing the direction of the magnetic field several billions of times a second the scientists were able to make the “mirror” vibrate at a speed of up to 25 percent of the speed of light..."Relatively little energy is therefore required in order to excite them out of their virtual state. In principle, one could also create other particles from vacuum, such as electrons or protons, but that would require a lot more energy."..."

Se også

[1] Nov 17, 2011, phys.org: Scientists create light from vacuum Citat: "... Scientists at Chalmers University of Technology have succeeded in creating light [ fotonpartikler ] from vacuum – observing an effect first predicted over 40 years ago...In fact, the vacuum is full of various particles that are continuously fluctuating in and out of existence. They appear, exist for a brief moment and then disappear again. Since their existence is so fleeting, they are usually referred to as virtual particles... By changing the direction of the magnetic field several billions of times a second the scientists were able to make the “mirror” vibrate at a speed of up to 25 percent of the speed of light..."Relatively little energy is therefore required in order to excite them out of their virtual state. In principle, one could also create other particles from vacuum, such as electrons or protons, but that would require a lot more energy."..."

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