Fotonien kehitys
Ehdotus ja fotonien kehitys – valon kvanttiteoria
In1901,GermanphysicistPlanck(Plank)foundtheenergydistributionlawoftheabsoluteblackbodyradiationspectrumunderthermalequilibriumconsistentwiththeexperiment.Thislawisthestartingpointforthedevelopmentofquantumtheory.Thebasisofthislawistoassumethatmatterhasdiscontinuouscharacteristicsoflightemittedandabsorbed,andthatlightisemittedorabsorbedbyafinitepart-lightquanta.
Theenergyεofthisphotonisproportionaltothevibrationfrequencyωoflight,andcanbeexpressedbythefollowingequation
TässäIsPlanck'sconstant.
WhenEinsteinpointedoutthatinadditiontoenergyε,animpulse(thedirectionofthisimpulseisconsistentwiththepropagationdirectionoflight)mustbeusedtodescribethephoton,thephotonTheexpressionhasonlygotaperfectform.
Jos aaltovektorikotetaan käyttöön, sen komponentti on yhtä suuri
whereλisthewavelength,andcosα,cosβ,cosγIsthecosineofthenormaldirectionofthelightwave,sotheimpulseformulaofthelightquantumcanbewritteninvectorform
photonaction
photonisTheelementaryparticlethattransmitselectromagneticinteractionisagaugeboson.Photonisthecarrierofelectromagneticradiation,andinquantumfieldtheory,photonisconsideredasthemediatorofelectromagneticinteraction.Comparedwithmostelementaryparticles,therestmassofaphotoniszero,whichmeansthatitspropagationspeedinvacuumisthespeedoflight.Likeotherquanta,photonshavewave-particleduality:photonscanshowthepropertiesofclassicwavessuchasrefraction,interference,anddiffraction;andtheparticlenatureofphotonscanbeprovedbythephotoelectriceffect.Photonscanonlytransmitquantizedenergy.Theyarelatticeparticlesandthemass-energyphaseofcirclequantumparticles.
Photonproperties
Aftertheestablishmentofquantumelectrodynamics,itisconfirmedthatphotonsarethemediaparticlesthattransmitelectromagneticinteractions.Chargedparticlesinteractbyemittingorabsorbingphotons.Thepairofpositiveandnegativechargedparticlescanbeannihilatedandconvertedintophotons,andtheycanalsobegeneratedinanelectromagneticfield.
Photonsareparticlesthatcarryenergyinlight.Theenergyofaphotonisproportionaltothefrequencyofthelightwave.Thehigherthefrequency,thehighertheenergy.Whenaphotonisabsorbedbyanatom,anelectrongainsenoughenergytotransitionfromtheinnerorbittotheouterorbit,andtheatomwiththeelectronictransitionchangesfromthegroundstatetotheexcitedstate.
Photonshaveenergy,Momentum,andmass.Massa-energiayhtälön mukaanE=mc2=hν,etsi i>m=hν/c2,
Becausethephotoncannotbestationary,ithasnostationarymass.Themasshereistherelativisticmassofthephoton.
Kvanttikenttäteorian mukaan positiivisten ja negatiivisten hiukkasten pari voidaan tuhota pariksi korkean energian gammafotoneiksi,japariksi korkeaenergisiä gammafotoneja, jotka voivat tuottaa jopakorkean lämpötilanparin. 15K, fotonien muuntaminen baryoneiksi, kuten protoneiksi ja neutroneiksi, voi tapahtua.
Thepositron-negativeelectronscattering(alsocalledBha-Bhascattering)representedbyFeynmandiagram,andthewavylinerepresentstheprocessofexchangingvirtualphotons.
Katso:Suhteellisuusteorian erikoisteoria
Fromtheperspectiveofwaves,photonshavetwopossiblepolarizationstatesandthreeorthogonalwavevectorcomponents,whichdetermineFromthepointofviewofparticles,therestmassofthephotoniszero,thechargeiszero,andthehalf-lifeisinfinite.Aphotonisagaugebosonwithaspinof1,sothenumberofleptons,baryons,andsingularnumbersareallzero.
Fotonin massat tiukasti nolla, mikä on oleellisesti yhtä suuri kuin Coulombin lain tiukka versioidenneliösuhde. Jos fotonmassa ei ole nolla, niin Coulombin laki ei ole tiukka käänteinen neliölaki. Kaikki liittyvät klassiset s, luottaa siihen oletukseen, että fotonssin staattinen massa on tiukasti nolla. Einsteinin massa-energiasuhteesta ja fotonienergiakaavasta fotomassan yläraja voidaan karkeasti saada:m=hν/< i>c2
Tässämon fotonmassan yläraja jaνonelektromagneettisen aallon taajuus, joka onSchumannin resonanssi erittäin matalalla taajuuskaistalla. Pienin tunnettu taajuus on noin 7,8 Hz (Hertz).
Thisvalueisonlytwoordersofmagnitudehigherthanthecurrentlyacceptedupperlimit.
KatsoPhotons:CanonicalBosons
Photonscanbeproducedinmanynaturalprocesses,forexample:inmolecules,atomsornucleifromhighenergylevelstolowenergyPhotonsareradiatedwhenthechargeisacceleratedduringtheleveltransition,andphotonsarealsoproducedwhenparticlesandantiparticlesareannihilated;intheabove-mentionedtimereversalprocess,photonscanbeabsorbed,thatis,molecules,atomsornucleitransitionfromlowenergylevelstohighenergylevels,Thegenerationofparticleandantiparticlepairs.
Fotonien nopeusvakuumissavalon nopeudella ja energianE ja vauhdinpsuhde onp=E/c ;Staattisen massan ja suhteellista mekaniikkaa sisältävien hiukkasten energia-momenttisuhde.
Valokuvan energia ja momentti liittyy vain fotonin taajuuteen ν; oritanssi liittyy vain aallonpituuteenλ. Siten valonmomentti onp=h/λ=hv/ c.
missäh kutsutaan Planckin vakioksi.
Päätelmä voidaan tehdä fotonien energia- ja momenttikaavoista
Theannihilationprocessofparticlesandtheirantiparticlesmustproduceatleasttwophotons.Thereasonisthatthetotalmomentumofthesystemcomposedofparticlesandtheirantiparticlesinthecenterofmasssystemiszero.Duetothelawofconservationofenergy,thetotalmomentumofthegeneratedphotonsmustalsobezero;becauseasinglephotonalwayshasanon-zeromomentum,thesystemOnlytwoormorephotonscanbegeneratedtosatisfythetotalmomentumofzero.Thefrequencyatwhichphotonsareproduced,thatis,theirenergy,isdeterminedbythelawofconservationofenergy-momentum(four-dimensionalmomentumconservation).Fromtheconservationofenergy-momentum,itcanbeseenthattheinverseprocessofparticleandantiparticleannihilation,thatis,theprocessoftwo-photongeneratingelectron-antielectronpairscannotbespontaneouslygeneratedinavacuum.
Photonissa on aaltohiukkasosaisuus
Thatistosay,photonnotonlyhasthecharacteristicsofoneparticlebyoneparticle,butalsohasthevolatilitylikesoundwave.Whentimeisaninstantaneousvalue,photonspropagateintheformofparticles;whentimeisanaveragevalue,photonspropagateintheformofwaves.Thewavenatureofphotonsisprovedbythediffractionofphotons,andtheparticlenatureofphotonsisprovedbythephotoelectriceffect.
Jotkut ovat sitä mieltä, että fotonin dynaaminen massabezero ja fotonin staattinen massa on väärin, muuten sen dynaaminen massa on ääretön. Mutta sen dynaaminen massa on olemassa. >,(Missä< i>hisPlanckin vakio),soitsmassvoidaan saadamassa-energiakaavasta:m=E/c2 =hv/c2jossac2 edustaa valonnopeuden neliötä. Tämän menetelmän ehdotti ensin Einstein.
PhotonTheory
Photonshavespeed,energy,momentum,mass,andcondensation.Itisimpossibleforphotonstostandstill.Photonscanbecomeothersubstances(suchasapairofpositiveandnegativeelectrons),butenergyandmomentumareconserved.[Withinafewnanoseconds)controlthepathandpolarizationofphotonswiththesamewavelengthasthecurrentopticalcommunicationnetwork.Thenewphotoniccircuitcanbeintegratedintotheexistingopticalcommunicationnetwork,therebysignificantlyimprovingtheperformanceofthenetwork.Thelatestresearchhastakenasteptowardstherealizationofopticalquantumcommunication.
ScientistsfromtheUniversityofBristol,Heriot-WattUniversity,andtheKavliInstituteforNanoscienceintheNetherlandspublishedthisstudyontherapidcontrolofthepathandpolarizationofsinglephotonsinthelatestissueofPhysicalReview"LearningExpress"magazine.
Whentheystudiedaquantumopticaldevicecomposedofcircuits,theyfoundthatasinglephotonwouldmovethroughthesecircuits,andthesecircuitscouldalsobereconfiguredtochangethepathandpolarizationdirectionofthephoton.However,suchquantumopticalcircuitscannotquicklymanipulatesingle-photonandmulti-photonstates.Inordertosolvethisproblem,theyusedalithiumniobatewaveguidethathasbeenproventobecapableofrapidmanipulationinexistingcommunicationmodulators,andprovedthatapplyingavoltagetothewaveguideneartheelectrodecanquicklymanipulateoneortwowavelengthsof1550nanometers.Thequantum(includingpathandpolarization)stateoflightcomposedofaphotonisexactlythewavelengthusedintheexistingcommunicationnetwork.
DamienBonooftheUniversityofBristol,wholedtheresearch,said:“Inthisexperiment,wedemonstratedtwocircuitconfigurations.Eachcircuitconfigurationleadstoadifferentquantumstate.Configurationonlytakesafewnanoseconds.Inpreviousexperiments,thecircuitcanbereconfiguredeveryfewseconds.Communicationnetworksuseswitchesmadeofthesametechnologytotransmitinformationbytesencodedbyopticalpulseseveryday.Intermsoftheabove,suchaswitchcanalsobeusedatthesingle-photonlevel."
Bonosaid:"Uptonow,themanipulationofthequantumstateoflightonthechiphasalwaysreliedonheaters,whichcanbeusedasaslowphaseshifter.Thelatestresearchshowsthatthelithiumniobatewaveguidecanuseacompletelydifferentmethodtomanipulatethequantumstateoflightmorequickly.Wecannotonlyopenandclosetheopticalpackettosendtraditionalinformationaccordingtotheprescribedroute,butalsoQuicklyprocessandmanipulatethequantumstateoflight."
Scientistspointedoutthatbeingabletoquicklycontrolthepolarizationandpathofasinglephotononasingleplatformisveryimportanttobasicquantumscienceandquantumtechnology.Bonosaidthatthelithiumniobatematerialsusedtomakethesedevicescanalsorandomlygeneratephotons.Inaddition,single-photondetectorswithsuperconductivitycanalsobeintegratedonsuchachip.Atechnologyplatformthatcombineslightsources,circuits,anddetectorsthatcanrandomlygeneratephotonscanbeusedinthefollowingareas:multiplephotonsourcesareusedtoobtainreliablesingle-photonsources,quantumrelaysrequiredforlong-distancequantumcommunications,Quantumkeydistributionusedinquantumcryptography,etc.
Inthepast,someold-fashionedradiosusedelectronictubes,andtheyhadtobewarmedupeachtimetheyworked.Withtheapplicationofsemiconductortubes,thepreheatingtimeissaved.Nowadays,similaradvanceshavetakenplaceinthefieldofopticalquantummodulationequipment.Inthepast,aheaterwasusedtoreconfigurethecircuitinafewseconds,anditwaspossibletoswitchtoanothercircuitinafewnanoseconds.Theuseoflithiumniobateasawaveguidedeviceisacommontechnicalmethodinthemodemera.Butwhowouldhavethoughtthataslightchangeinthemediocrephotoelectricconversionequipmentcouldhelpthemostcutting-edgeopticalquantumcommunicationresearchtomakeabreakthrough?Withtheintegrationoflightsources,circuits,anddetectors,theworkloadofquantumcommunicationresearcherscanbereducedalot.
Aiheeseen liittyvät tapahtumat
Huazhongin tiede- ja teknologiayliopiston professorit määrittävät uudelleen fotonpyyhkäisymassan ylärajan
ProfessorsofHuazhongUniversityofScienceandTechnologyredefinetheupperlimitofphotonrestingmassSomepeopleintheindustrybelievethatthezerorestmassofphotonsisoneofthebasicassumptionsofclassicalelectromagnetictheory.Butsomescientistsbelievethatphotonsmayhaverestmass.Iftheexperimentfinallydetectsthatthephotonhasarestmass,thensomeclassicaltheorieswillhavetochange.
IntheAmerican"PhysicalReviewLetters"(PhysicalReviewLetters),aspecialarticleintroduced:"AnewexperimentcompletedbyChinesescientistLuoJunandothersshowsthatunderanycircumstances,Therestmassofaphotonwillnotexceed10totheminus54kilogram.Thisresultis1/20ofthepreviouslyknownupperlimitofphotonmass.”LuoJunandhiscolleaguesusedanovelexperimentalmethodtoexperimentinacave.Theupperlimitoftherestingmassofphotonsintheroomhasbeenfurtherincreasedbyatleastanorderofmagnitude.
Itisreportedthatifthephotonhasastaticmass,althoughitwillnotaffectpeople’sdailylife,theconsequenceswillbefundamental-forexample,thespeedoflightwillchangewiththechangeofwavelength,andLightwaveswillbeabletoproducelongitudinalvibrationsjustlikesoundwaves.