Qhov sib txawv tseem ceeb ntawm QED thiab QCD yog QED piav qhia txog kev sib cuam tshuam ntawm cov khoom siv hluav taws xob nrog lub tshuab hluav taws xob, qhov QCD piav qhia kev cuam tshuam ntawm quarks thiab gluons.
QED yog quantum electrodynamics whereas QCD yog quantum chromodynamics. Ob nqe lus no piav qhia txog tus cwj pwm ntawm cov nplai me me xws li subatomic particles.
QED yog dab tsi?
QED yog quantum electrodynamics. Nws yog ib txoj kev xav uas piav qhia txog kev sib cuam tshuam ntawm cov khoom siv hluav taws xob nrog electromagnetic teb. Piv txwv li, nws tuaj yeem piav qhia txog kev sib cuam tshuam ntawm lub teeb thiab teeb meem (uas tau them cov khoom). Tsis tas li ntawd, nws piav qhia txog kev sib cuam tshuam ntawm cov khoom siv hluav taws xob thiab. Yog li, nws yog ib txoj kev xav sib txheeb. Tsis tas li ntawd, qhov kev xav no tau raug suav tias yog qhov kev xav ntawm lub cev zoo txij li lub sijhawm sib nqus ntawm cov khoom, xws li muons, pom zoo nrog qhov kev xav no rau cuaj tus lej.
Yeej, kev sib pauv ntawm photons ua raws li lub zog ntawm kev sib cuam tshuam vim hais tias muaj peev xwm hloov lawv qhov ceev thiab kev taw qhia ntawm kev txav thaum tso tawm lossis nqus cov photons. Ntxiv mus, photons tej zaum yuav raug tso tawm raws li photons dawb uas tshwm sim li lub teeb (los yog lwm hom EMR - hluav taws xob hluav taws xob).
Daim duab 01: QED Cov Cai Kawm Qib Nrab
Kev sib cuam tshuam ntawm cov khoom raug them tshwm sim hauv cov kauj ruam uas muaj qhov nyuaj ntxiv. Qhov ntawd txhais tau tias; thawj zaug, tsuas yog ib qho virtual (tsis pom thiab tsis paub meej) photon, thiab tom qab ntawd hauv txheej txheem thib ob, muaj ob lub photons uas koom nrog kev sib cuam tshuam thiab lwm yam. Ntawm no, kev sib cuam tshuam tshwm sim ntawm kev sib pauv ntawm photons.
QCD?
QCD yog quantum chromodynamics. Nws yog ib txoj kev xav uas piav txog lub zog muaj zog (natural, kev sib cuam tshuam uas tshwm sim ntawm subatomic hais). Txoj kev xav tau tsim los ua ib qho piv txwv rau QED. Raws li QED, electromagnetic cuam tshuam ntawm cov khoom them nqi tshwm sim los ntawm kev nqus lossis emission ntawm photons, tab sis nrog cov khoom tsis muaj nqi, nws tsis tuaj yeem ua tau. Raws li QCD, cov khoom siv quab yuam yog "gluons", uas tuaj yeem xa cov quab yuam ntawm cov khoom hu ua quarks. Feem ntau, QCD piav qhia txog kev sib cuam tshuam ntawm quarks thiab gluons. Peb muab ob qho tib si quarks thiab gluons nrog tus lej quantum hu ua "xim".
Hauv QCD, peb siv peb hom "xim" los piav qhia tus cwj pwm ntawm quarks: liab, ntsuab thiab xiav. Muaj ob hom xim-nruab nrab raws li baryons thiab mesons. Baryons suav nrog peb subatomic hais xws li protons thiab neutrons. Peb cov quarks no muaj cov xim sib txawv thiab cov ntaub ntawv nruab nrab ntawm qhov sib xyaw ua ke ntawm peb cov xim. Ntawm qhov tod tes, mesons muaj khub ntawm quarks thiab antiquarks. Cov xim ntawm antiquarks tuaj yeem cuam tshuam cov xim ntawm quark.
Cov khoom quark tuaj yeem cuam tshuam los ntawm lub zog muaj zog (los ntawm kev sib pauv gluons). Gluons kuj muaj xim; yog li, yuav tsum muaj 8 gluons ib qho kev sib cuam tshuam thiaj li tso cai rau kev sib cuam tshuam ntawm peb xim ntawm quark. Txij li thaum gluons nqa cov xim, lawv tuaj yeem cuam tshuam nrog ib leeg (qhov sib txawv, photons hauv QED tsis tuaj yeem cuam tshuam nrog ib leeg). Yog li, nws piav qhia meej txog kev kaw ntawm quarks (quarks tsuas yog pom nyob rau hauv kev sib xyaw ua ke hauv baryons thiab mesons). Yog li, qhov no yog qhov kev xav tom qab QCD.
Qhov txawv ntawm QED thiab QCD yog dab tsi?
QED stands rau quantum electrodynamics qhov twg QCD stands rau quantum chromodynamics. Qhov sib txawv tseem ceeb ntawm QED thiab QCD yog tias QED piav qhia txog kev sib cuam tshuam ntawm cov khoom siv hluav taws xob nrog lub tshuab hluav taws xob, thaum QCD piav qhia txog kev cuam tshuam ntawm quarks thiab gluons.
Cov infographic hauv qab no nthuav tawm ntau qhov sib piv txog qhov sib txawv ntawm QED thiab QCD hauv cov ntsiab lus ntxiv.
Summary – QED vs QCD
QED yog quantum electrodynamics qhov twg QCD yog quantum chromodynamics. Qhov sib txawv tseem ceeb ntawm QED thiab QCD yog tias QED piav qhia txog kev sib cuam tshuam ntawm cov khoom siv hluav taws xob nrog lub tshuab hluav taws xob, thaum QCD piav qhia txog kev cuam tshuam ntawm quarks thiab gluons.
