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Rivnya nnya Diraka relyativistsko invariantne rivnyannya ruhu dlya bispinornogo klasichnogo polya elektrona zastosovne takozh dlya opisu inshih tochkovih fermioniv zi spinom 1 2 Jogo vpershe zapisav Pol Dirak u 1928 Rivnyannya Diraka prizvelo do poyasnennya napivcilogo spinu elektrona ta do vidkrittya antichastinok yakimi dlya elektrona ye pozitroni Chastinku zi spinom 1 2 opisuye nerelyativistske rivnyannya Pauli do yakogo zvoditsya rivnyannya Diraka pri malih energiyah Zmist 1 Viglyad rivnyannya 2 Pobudova rivnyannya Diraka 3 Relyativistsko kovariantna forma 3 1 Poyasnennya 3 2 Zapis z vikoristannyam Feynman slash 4 Dirakovski bilinijni formi 5 Rozv yazki 6 Div takozh 7 Primitki 8 Posilannya 9 LiteraturaViglyad rivnyannya RedaguvatiRivnyannya Diraka zapisuyetsya v viglyadi m c 2 a 0 c j 1 3 a j p j ps x t i ℏ ps t x t displaystyle left mc 2 alpha 0 c sum j 1 3 alpha j hat p j right psi mathbf x t i hbar frac partial psi partial t mathbf x t nbsp de m displaystyle m nbsp masa elektrona abo inshogo fermiona sho opisuyetsya rivnyannyam c displaystyle c nbsp shvidkist svitla p j i ℏ j x j displaystyle hat p j i hbar partial j bar frac partial partial x j nbsp tri operatori komponent impulsu x y z ℏ h 2 p displaystyle hbar h over 2 pi nbsp h displaystyle h nbsp stala Planka x x y z i t prostorovi koordinati i chas vidpovidno ta ps x t displaystyle psi mathbf x t nbsp chotirikomponentna kompleksna hvilova funkciya bispinor ps x t ps 1 x t ps 2 x t ps 3 x t ps 4 x t displaystyle psi mathbf x t left begin matrix psi 1 mathbf x t psi 2 mathbf x t psi 3 mathbf x t psi 4 mathbf x t end matrix right nbsp a 0 a 1 a 2 a 3 displaystyle alpha 0 alpha 1 alpha 2 alpha 3 nbsp linijni operatori nad prostorom bispinoriv yaki diyut na hvilovu funkciyu Ci operatori pidibrani taki chinom sho kozhna para takih operatoriv antikomutuye a kvadrat kozhnogo dorivnyuye odinici a i a j a j a i displaystyle alpha i alpha j alpha j alpha i nbsp de i j displaystyle i neq j nbsp i indeksi i j displaystyle i j nbsp zminyuyutsya vid 0 do 3 a i 2 1 displaystyle alpha i 2 1 nbsp dlya i displaystyle i nbsp vid 0 do 3 U danomu predstavlenni ci operatori ye matricyami rozmiru 4 4 ce minimalnij rozmir matric dlya yakih vikonuyutsya umovi antikomutaciyi i nazivayutsya alfa matricyami DirakaVes operator v duzhkah v livij chastini rivnyannya nazivayetsya operatorom Diraka tochnishe v suchasnij terminologiyi jogo slid nazivati gamiltonianom Diraka oskilki operatorom Diraka zazvichaj nazivayut kovariantnij operator D z yakim rivnyannya Diraka zapisuyetsya u viglyadi DPS 0 yak opisano v nastupnomu zauvazhenni U suchasnij fizici chasto vikoristovuyetsya kovariantna forma zapisu 1 rivnyannya Diraka detalnishe div nizhche i ℏ c g m m m c 2 ps 0 displaystyle left i hbar c gamma mu partial mu mc 2 right psi 0 nbsp Pobudova rivnyannya Diraka RedaguvatiRivnyannya Diraka relyativistske uzagalnennya rivnyannya Shredingera H ps t i ℏ d d t ps t displaystyle hat H left psi t right rangle i hbar d over dt left psi t right rangle nbsp Dlya zruchnosti mi hto budemo pracyuvati v koordinatnomu predstavlenni v yakomu stan sistemi zadayetsya hvilovoyu funkciyeyu ps x t V comu predstavlenni rivnyannya Shredingera zapisuyetsya u viglyadi H ps x t i ℏ ps x t t displaystyle hat H psi mathbf x t i hbar frac partial psi mathbf x t partial t nbsp de gamiltonian H displaystyle hat H nbsp teper diye na hvilovu funkciyu Gamiltonian potribno viznachiti tak shob vin opisuvav povnu energiyu sistemi Dlya nerelyativistskogo vilnogo elektrona yakij ni z chim ne vzayemodiye izolovanij vid usih storonnih poliv gamiltonian maye viglyad analogichnij kinetichnij energiyi v klasichnij mehanici yaksho ne brati do uvagi ni relyativistskih popravok ni spinu H j 1 3 p j 2 2 m displaystyle hat H sum j 1 3 frac hat p j 2 2m nbsp de pj operatori proyekcij impulsu de indeks j 1 2 3 oznachaye dekartovi koordinati Kozhen takij operator diye na hvilovu funkciyu yak prostorova pohidna p j ps x t d e f i ℏ ps x t x j displaystyle hat p j psi mathbf x t stackrel mathrm def i hbar frac partial psi mathbf x t partial x j nbsp Shob opisati relyativistsku chastinku potribno znajti inshij gamiltonian Pri comu ye pidgruntya vvazhati sho operator impulsu zberigaye shojno navedene viznachennya Vidpovidno do relyativistskogo spivvidnoshennya povnu energiyu sistemi mozhna viraziti yak E m c 2 2 j 1 3 p j c 2 displaystyle E sqrt mc 2 2 sum j 1 3 p j c 2 nbsp Ce privodit do virazu m c 2 2 j 1 3 p j c 2 ps i ℏ d ps d t displaystyle sqrt mc 2 2 sum j 1 3 p j c 2 psi i hbar frac d psi dt nbsp Ce ne zovsim zadovilne rivnyannya oskilki ne vidno yavnoyi lorenc kovariantnosti yaka virazhaye formalne rivnoprav ya chasu i prostorovih koordinat sho ye odnim z narizhnih kameniv specialnoyi teoriyi vidnosnosti a krim togo napisanij korin z operatora ne vipisanij yavno Odnak pidnesennya do kvadratu livoyi ta pravoyi chastin privodit do yavno lorenc kovariantnogo rivnyannya Klejna Gordona Dirak zaproponuvav sho oskilki prava chastina rivnyannya mistit pershu pohidnu po chasu to i liva chastina povinna mati tilki pohidni pershogo poryadku po prostorovih koordinatah inakshe kazhuchi operatori impulsu v pershij stepeni Todi prijmayuchi sho koeficiyenti pered pohidnimi yaku b prirodu voni ne mali postijni vnaslidok odnoridnosti prostoru zalishayetsya tilki zapisati i ℏ d ps d t c i 1 3 a i p i a 0 m c 2 ps displaystyle i hbar frac d psi dt left c sum i 1 3 alpha i p i alpha 0 mc 2 right psi nbsp ce i ye rivnyannya Diraka dlya vilnoyi chastinki Odnak koeficiyenti a i displaystyle alpha i nbsp she ne viznacheni Yaksho pripushennya Diraka pravilne to prava chastina pidnesena do kvadratu povinna dati m c 2 2 j 1 3 p j c 2 displaystyle mc 2 2 sum j 1 3 p j c 2 nbsp tobto m c 2 a 0 c j 1 3 a j p j 2 m c 2 2 j 1 3 p j c 2 displaystyle left mc 2 alpha 0 c sum j 1 3 alpha j p j right 2 mc 2 2 sum j 1 3 p j c 2 nbsp Rozkrivayuchi duzhki v livij chastini otrimanogo rivnyannya mozhna znajti umovi na a a i a j a j a i 0 displaystyle alpha i alpha j alpha j alpha i 0 nbsp dlya vsih i j 0 1 2 3 i j displaystyle i j 0 1 2 3 i neq j nbsp a i 2 1 displaystyle alpha i 2 1 nbsp dlya vsih i 0 1 2 3 displaystyle i 0 1 2 3 nbsp abo skorocheno zapisavshi vse razom a i a j a j a i 2 d i j displaystyle alpha i alpha j alpha j alpha i 2 delta ij nbsp dlya i j 0 1 2 3 displaystyle i j 0 1 2 3 nbsp abo she korotshe koristuyuchis figurnimi duzhkami dlya poznachennya antikomutatoriv a i a j 2 d i j displaystyle left alpha i alpha j right 2 delta ij nbsp dlya i j 0 1 2 3 displaystyle i j 0 1 2 3 nbsp de antikomutator sho viznachayetsya yak A B AB BA i dij simvol Kronekera yakij prijmaye znachennya 1 yaksho dva indeksi rivni a v protilezhnomu vipadku 0 Div algebra Kliforda Oskilki taki spivvidnoshennya ne mozhut vikonuvatis dlya zvichajnih chisel adzhe chisla komutuyut a a ni zalishayetsya pripustiti sho a ce deyaki linijni operatori abo matrici todi odinici j nuli v pravij chastini spivvidnoshen mozhna vvazhati vidpovidno odinichnim i nulovim operatorom abo matriceyu i mozhna namagatisya znajti konkretnij nabir a skoristavshis danimi spivvidnoshennyami i ce vdayetsya Staye zrozumilo sho hvilova funkciya povinna buti ne odnokomponentnoyu tobto ne skalyarnoyu a vektornoyu mayuchi na uvazi vektori yakogos abstraktnogo vnutrishnogo prostoru ne pov yazanogo pryamo zi zvichajnim fizichnim prostorom abo prostorom chasom Matrici povinni buti ermitovi tak shob gamiltonian tezh buv ermitovim operatorom Najmensha rozmirnist matric sho zadovolnyayut vkazanim kriteriyam chotiri tobto ce kompleksni matrici 4 4 hocha konkretnij vibir matric abo predstavlennya ne ye odnoznachnim Ci matrici utvoryuyut grupu v yakij grupova operaciya matrichne mnozhennya Hocha vibir predstavlennya ciyeyi grupi ne vplivaye na vlastivosti rivnyannya Diraka vin vplivaye na fizichnij zmist komponent hvilovoyi funkciyi Hvilova funkciya v takomu razi povinna buti chotirivimirnim kompleksnim abstraktnim ne pov yazanim pryamo z vektorami zvichajnogo prostoru chasu bispinornim polem U vstupi bulo navedeno predstavlennya yake vikoristovuvav Dirak Ce predstavlennya mozhna pravilno zapisati yak a 0 I 0 0 I a j 0 s j s j 0 displaystyle alpha 0 begin bmatrix I amp 0 0 amp I end bmatrix quad alpha j begin bmatrix 0 amp sigma j sigma j amp 0 end bmatrix nbsp de 0 i I 2 2 nulova i odinichna matrici vidpovidno i sj j 1 2 3 matrici Pauli sho ye matrichnim predstavlennyam kvaternioniv pro yaki davno vidomo sho voni antikomutuyut Gamiltonian v comu rivnyannya H m c 2 a 0 c j 1 3 a j p j displaystyle hat H mc 2 alpha 0 c sum j 1 3 alpha j p j nbsp nazavayetsya gamiltonianom Diraka Dlya zvichajnogo rivnyannya Diraka v dvovimirnomu prostori abo v trivimirnomu ale z m 0 zamist alfa matric dostatno lishe matric Pauli zamist chotirikomponentnogo bispinornogo polya pri comu rol hvilovoyi funkciyi bude vikonuvati dvokomponentne spinorne Relyativistsko kovariantna forma RedaguvatiKovariantnij zapis rivnyannya Diraka dlya vilnoyi chastinki maye takij viglyad i ℏ c m 0 3 g m m m c 2 ps 0 displaystyle left i hbar c sum mu 0 3 gamma mu partial mu mc 2 right psi 0 nbsp abo vikoristovuyuchi pravilo Ejnshtejna sumuvannya po indeksah sho povtoryuyutsya tak i ℏ c g m m m c 2 ps 0 displaystyle left i hbar c gamma mu partial mu mc 2 right psi 0 nbsp Poyasnennya Redaguvati Chasto korisno buvaye koristuvatis rivnyannyam Diraka v relyativistsko kovariantnij formi v yakij prostorovi ta chasovi koordinati formalno rivnopravni Operator impulsu p displaystyle hat p nbsp diye yak prostorova pohidna p ps x t i ℏ ps x t displaystyle mathbf p psi mathbf x t i hbar nabla psi mathbf x t nbsp Mnozhachi rivnyannya Diraka z kozhnogo boku na a0 zgaduyuchi sho a0 I i pidstavlyayuchi jogo u viznachennya dlya p displaystyle hat p nbsp rivnyannya Diraka nabiraye viglyadu i ℏ c a 0 c t j 1 3 a 0 a j x j m c 2 ps 0 displaystyle left i hbar c left alpha 0 frac partial c partial t sum j 1 3 alpha 0 alpha j frac partial partial x j right mc 2 right psi 0 nbsp Chotiri gamma matrici viznachayutsya yak g 0 d e f a 0 g j d e f a 0 a j displaystyle gamma 0 stackrel mathrm def alpha 0 quad gamma j stackrel mathrm def alpha 0 alpha j nbsp Ci matrici mayut vlastivis sho g m g n 2 h m n I m n 0 1 2 3 displaystyle left gamma mu gamma nu right 2 eta mu nu cdot I quad mu nu 0 1 2 3 nbsp de h metrika ploskogo prostoru Ci spivvidnoshennya viznachayut algebru Kliforda sho nazivayetsya algebroyu Diraka Rivnyannya Diraka teper mozhna zapisati vikoristovuyuchi chotiri vektor x ct x yak i ℏ c m 0 3 g m m m c 2 ps 0 displaystyle left i hbar c sum mu 0 3 gamma mu partial mu mc 2 right psi 0 nbsp U cij formi rivnyannya Diraka mozhna otrimati z dopomogoyu znahodzhennya ekstremumu diyi S ps i ℏ c m g m m m c 2 ps d 4 x displaystyle mathcal S int bar psi i hbar c sum mu gamma mu partial mu mc 2 psi d 4 x nbsp de ps d e f ps g 0 displaystyle bar psi stackrel mathrm def psi dagger gamma 0 nbsp nazivayetsya priyednanoyu matriceyu Diraka dlya ps Ce osnova dlya vikoristannya rivnyannya Diraka v kvantovij teoriyi polya V cij formi elektromagnitnu vzayemodiyu mozhna prosto dodati rozshirivshi chastinnu pohidnu do kalibruvalnoyi pohidnoyi m D m m i e A m displaystyle partial mu rightarrow D mu partial mu ieA mu nbsp Zapis z vikoristannyam Feynman slash Redaguvati Inkoli vikoristovuyetsya zapis z vikoristannyam perekreslenih matric Feynman slash Prijnyavshi poznachennya a m g m a m displaystyle a leftrightarrow sum mu gamma mu a mu nbsp bachimo sho rivnyannya Diraka mozhna zapisati yak i ℏ c m c 2 ps 0 displaystyle i hbar c partial mc 2 psi 0 nbsp i viraz dlya diyi zapisuyetsya u viglyadi S ps i ℏ c m c 2 ps d 4 x displaystyle mathcal S int bar psi i hbar c partial mc 2 psi d 4 x nbsp Dirakovski bilinijni formi RedaguvatiYe p yat riznih nejtralnih dirakovskih bilinijnih form bez pohidnih S skalyar ps ps displaystyle bar psi psi nbsp skalyar P parnij P psevdoskalyar ps g 5 ps displaystyle bar psi gamma 5 psi nbsp skalyar P neparnij V Vektor ps g m ps displaystyle bar psi gamma mu psi nbsp vektor P parnij A aksialnij vektor ps g m g 5 ps displaystyle bar psi gamma mu gamma 5 psi nbsp vektor P neparnij T tenzor ps s m n ps displaystyle bar psi sigma mu nu psi nbsp antisimetrichnij tenzor de s m n i 2 g m g n displaystyle sigma mu nu frac i 2 left gamma mu gamma nu right nbsp i g 5 g 5 i 4 ϵ m n r l g m g n g r g l i g 0 g 1 g 2 g 3 displaystyle gamma 5 gamma 5 frac i 4 epsilon mu nu rho lambda gamma mu gamma nu gamma rho gamma lambda i gamma 0 gamma 1 gamma 2 gamma 3 nbsp Rozv yazki RedaguvatiHarakternoyu osoblivistyu rivnyannya Diraka ye te sho dlya vilnoyi chastinki vono maye 4 rozv yazki yaki interpretuyutsya yak elektron zi spinom 1 2 elektron zi spinom 1 2 pozitron zi spinom 1 2 pozitron zi spinom 1 2 Div takozh RedaguvatiZitterbewegung Rivnyannya Klejna Gordona Teorema Atiyi Zingera pro indeks Spinor Fermion DirakaPrimitki Redaguvati Oskilki i forma z alfa matricyami lorenc kovariantna pravilnishe nazivati formu z gamma matricyami prosto chotirivimirnoyu a pri zamini zvichajnih pohidnih na kovariantni vona dast zagalnokovariantnij zapis rivnyannya Diraka Posilannya RedaguvatiLekciyi z kvantovoyi fizikiLiteratura RedaguvatiVakarchuk I O Kvantova mehanika 4 e vidannya dopovnene L LNU im Ivana Franka 2012 872 s Fedorchenko A M Kvantova mehanika termodinamika i statistichna fizika Teoretichna fizika K Visha shkola 1993 T 2 415 s Yuhnovskij I R Osnovi kvantovoyi mehaniki K Libid 2002 392 s Byorken Dzh D Drell S D Relyativistskaya kvantovaya teoriya M Nauka 1978 T 1 296 s Dajson F Relyativistskaya kvantovaya mehanika Izhevsk RHD 2009 248 s Dirak P A M Principy kvantovoj mehaniki M Nauka 1979 440 s Dirak P A M Relyativistskoe volnovoe uravnenie elektrona Uspehi fizicheskih nauk 1979 T 129 vyp 4 S 681 691 Zi E Kvantovaya teoriya polya v dvuh slovah Izhevsk RHD 2009 632 s Peskin M Shryoder D Vvedenie v kvantovuyu teoriyu polya Izhevsk RHD 2001 784 s Shiff L Kvantovaya mehanika M IL 1957 476 s Shankar R Principles of Quantum Mechanics Plenum 1994 Thaller B The Dirac Equation Springer 1992 Rivnyannya Diraka v Fizichnij enciklopediyi nbsp Ce nezavershena stattya z fiziki Vi mozhete dopomogti proyektu vipravivshi abo dopisavshi yiyi Otrimano z https uk wikipedia org w index php title Rivnyannya Diraka amp oldid 38477646