Ali je kvantna teorija nastala kot čista raziskava?

Ali je kvantna teorija nastala kot čista raziskava?


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Pred kratkim sem prebral razpravo o nesmiselnosti zahtevanja "uporabnosti" od raziskovalnih prizadevanj, saj je možen izid nepredvidljiv. Kot dokaz za to trditev je sledil seznam naključnih dokumentov, ki so bili očitno neuporabni ali zgolj akademskega pomena. Eden od njih je bil razvoj kvantne teorije na začetku 20. stoletja.

Nočem se osredotočati na temo same razprave. Namesto tega sem se vprašal, ali je ta predpostavka, da je "kvantna teorija nastala kot čisto akademsko/intelektualno delo", resnična. Konec koncev je to svet postindustrijske revolucije in patenti, ki obravnavajo toploto/elektriko, so morda spodbujali potrebe družbe ... ali pa tudi ne. Nikjer nisem našel dokazov za ali proti. Nato se bom obrnil na ljudi, ki so bolj izobraženi od mene.


Kolikor lahko razberem iz zgodovine, bi bilo netočno trditi, da je kvantna teorija nastala popolnoma kot čista raziskava ali pa da ima svoj izvor v uporabni znanosti. Za postavitev odra so v bistvu vključena tri obdobja:

1900-1913: Planckov dokument o sevanju črnega telesa (1900), Einsteinov dokument o fotoelektričnem učinku (1905).

1913-1927: Stara kvantna teorija, Bohrov model, teorija BKS.

1927: V približno enem letu nastane nova kvantna teorija, ki je v bistvu teorija v svoji sodobni obliki.

Planck je skoraj v celoti deloval v svojem teoretskem svetu in njegovo delo je takrat veljalo za zelo nejasno. Kruh in maslo si je pripravil kot teoretik na univerzi. (Zdi se, da so bile trditve, da so Planck financirala podjetja z žarnicami, napačne.) Čeprav je bil Einstein dokaj kompetenten eksperimentator, izumitelj in inženir in je nekaj časa delal na švicarskem patentnem uradu, je bilo njegovo delo glede kvantitet precej pred časom. , in zdi se, da je bila čista raziskava, ki je ni motivirala nobena aplikacija.

Ko vstopimo v Bohrovo dobo, se kvantna teorija sama po sebi oblikuje in opazimo močno medsebojno delovanje teorije in eksperimenta, pogosto z jasnimi aplikacijami. Spektroskopija je bila bogata z aplikacijami pred, med in po tem obdobju. Na primer, ljudi je zanimalo določanje sestave plinov iz njihovih spektrov. Moseleyjevo delo na rentgenskem spektru in atomskem številu je bilo izvedeno v tesnem sodelovanju z Bohrom, kar je povzročilo na primer odkritje hafnija. Vsa kemija je ena velika aplikacija kvantne mehanike, kemija pa je bogata z aplikacijami. Očitno je skupina, osredotočena na Bohra, pričakovala, da bo njihovo delo imelo uporabo v kemiji, atomski in molekularni fiziki, in zagotovo je bilo.

S prihodom sodobne kvantne teorije leta 1927 smo zelo hitro začeli videti aplikacije. Od tega časa do leta, ko je bil obratovan prvi jedrski kup (1942), je minilo le 15 let in težko si predstavljam, da se jedrska energija razvija brez kvantne mehanike.

Zdi se, da zgodovina tranzistorja bolj ali manj sovpada z obdobjem, v katerem se je razvijala kvantna mehanika. Prvi patent je dal Lilienfeld leta 1925, vendar je bilo videti, da je bilo potrebno veliko časa za napredek, predvsem zato, ker ljudje niso mogli dovolj dobro očistiti polprevodnikov. Lilienfeld je doktoriral iz fizike in imel Plancka za enega od svojih svetovalcev pri tezi. Začel je kot akademski fizik v Leipzigu, nato pa prestopil na delo v industriji v ZDA.

Nekatera zgodnja dela na področju kvantne fizike so bila izvedena s financiranjem bogatih posameznikov in ne vlad ali univerz. Konference Solvay je financiral kemik in industrialec Solvay, pomemben eksperiment Stern-Gerlach, ki je bil v težkih časih v Nemčiji, ko je hiperinflacija naraščala, pa je plačal ameriški bankir Henry Goldman. Rekel bi, da so te povezave dokaz tistega, kar se zdi tipična situacija glede povezav kvantne mehanike z aplikacijami. Ljudje, kot je kemik Solvay, so zagotovo pričakovali, da bodo prijavljene, vendar prijave niso bile takojšnje in donosne, zato se Goldman in Solvay nista videla kot vlagatelji, ampak kot donatorji.


"Kvantna teorija izvira iz Planckovega članka iz leta 1900 o sevanju črnega telesa in Einsteinovega članka iz leta 1905 o fotoelektričnem učinku." - @jamesqf ima glede tega dejstva prav. A glede abstraktnosti teh problemov nima prav. Nasprotno:

Mnogi izumitelji so tiste dni poskušali izumiti nove "žarke". Raziskali so tako težave nastajanja žarkov kot učinke, ki jih povzročajo žarki. In cilj je bil popolnoma resničen - najti nekaj koristnega. Najboljši rezultat so bili rentgenski žarki. Toda to ne pomeni, da so drugi raziskovalci želeli imeti praktične rezultate. Preprosto včasih so imeli srečo, včasih (pogosteje) pa ne. In zakoni o fotoelektriki so bili zanje zelo pomembni.

Zakoni sevanja črnega telesa so bili uporabni zaradi težav, omenjenih v prejšnjem odstavku, in ne samo to. Še pomembnejša tema tistega časa je bil izum novih motorjev. In izumitelji so za to želeli poznati zakone termodinamike. Ta zakon je bil zanje tudi pomemben in koristen, saj je pomagal bolje razumeti temo.

Razdalja med "abstraktno znanostjo" in "praktično uporabo" je bila v tistih časih tako blizu fizike, da v fiziki praktično sploh ni bilo abstraktne znanosti. Najbolj abstraktni znanstveni predmeti teh dni - operaterji Heavyside in kvaterioni Hamiltona so neposredno omogočili pošiljanje sporočil in radia brez izgub. Toda čas ločitve "abstraktne" znanosti je bil blizu - Heavyside, ki je prinesel milijarde telefonskim/telegrafskim podjetjem, je leta 1920 v Angliji umrl v revščini.


Kvantna teorija

S prehodom v 20. stoletje je področje fizike doživelo dve veliki preobrazbi, približno hkrati. Prva je bila Einsteinova splošna teorija relativnosti, ki je obravnavala univerzalno področje fizike. Druga je bila kvantna teorija, ki je predlagala, da energija obstaja kot diskretni paketi - vsak se imenuje "kvokvant". Ta nova veja fizike je znanstvenikom omogočila, da opišejo interakcijo med energijo in snovjo skozi subatomsko področje.

Einstein je kvantno teorijo videl kot sredstvo za opis narave na atomski ravni, vendar je dvomil, da podpira & kvotno podlago za celotno fiziko. & Quot; Mislil je, da opisovanje resničnosti zahteva trdne napovedi, ki jim sledijo neposredna opazovanja. Toda posameznih kvantnih interakcij ni mogoče neposredno opazovati, zato kvantnim fizikom ne preostane drugega, kot da napovedujejo verjetnost, da se bodo dogodki zgodili. Izziv Einsteina je fizik Niels Bohr zagovarjal kvantno teorijo. Trdil je, da samo dejanje posrednega opazovanja atomskega področja spremeni rezultat kvantnih interakcij. Po Bohru kvantne napovedi, ki temeljijo na verjetnosti, natančno opisujejo resničnost.

Niels Bohr in Max Planck, dva od ustanoviteljev kvantne teorije, sta za svoje delo na kvantah prejela Nobelovo nagrado za fiziko. Einstein velja za tretjega ustanovitelja kvantne teorije, ker je svetlobo opisal kot kvante v svoji teoriji o fotoelektričnem učinku, za katero je leta 1921 dobil Nobelovo nagrado.

15. maj 1935: The Fizični pregled objavlja dokument Einstein, Podolsky in Rosen (EPR), ki trdi, da ovrže kvantno teorijo.

Časopisi so Einsteinovo skepticizem glede "nove fizike" hitro posredovali širši javnosti. Einsteinov dokument & quot; Ali se lahko šteje, da je kvantno-mehanski opis fizične resničnosti popoln? & Quot; Niels Bohr je napisal zavrnitev. Sodobni poskusi so kljub Einsteinovim nasprotovanjem potrdili kvantno teorijo. Vendar pa je dokument EPR predstavil teme, ki so osnova za večino današnjih fizikalnih raziskav.

Einstein in Niels Bohr sta začela izpodbijati kvantno teorijo na prestižni konferenci Solvay leta 1927, ki so se je udeležili vrhunski fiziki tistega časa. Po večini te javne razprave je zmagal Bohr.


Zgodnje življenje

Max Karl Ernst Ludwig Planck je bil šesti otrok uglednega pravnika in profesorja prava na Univerzi v Kielu. Dolga družinska tradicija predanosti cerkvi in ​​državi, odličnost v znanosti, nepokvarjenost, konservativnost, idealizem, zanesljivost in velikodušnost so se močno ukoreninili v Planckovem življenju in delu. Ko je bil Planck star devet let, je njegov oče dobil sestanek na univerzi v Münchnu, Planck pa je vstopil v znano mestno gimnazijo Maximilian, kjer je učitelj Hermann Müller spodbudil njegovo zanimanje za fiziko in matematiko. Toda Planck je bil odličen pri vseh predmetih in se je po diplomi pri 17 letih soočil s težko odločitvijo o karieri. Končno se je odločil za fiziko pred klasično filologijo ali glasbo, ker je nepristransko prišel do zaključka, da je v fiziki njegova največja izvirnost. Glasba je kljub temu ostala sestavni del njegovega življenja. Imel je dar absolutne višine in bil odličen pianist, ki je vsak dan našel umirjenost in veselje ob klaviaturi, užival je predvsem v delih Schuberta in Brahmsa. Rad je imel tudi na prostem, vsak dan na dolge sprehode ter pohodništvo in plezanje v hribe na počitnicah, tudi v pozni starosti.

Planck je jeseni 1874 vstopil na univerzo v Münchnu, vendar pri profesorju fizike Philippu von Jollyju ni našel spodbude. Med letom, ki ga je preživel na univerzi v Berlinu (1877–78), ga predavanja Hermanna von Helmholtza in Gustava Roberta Kirchhoffa niso navdušila, kljub temu da so bili raziskovalci. Njegove intelektualne sposobnosti so bile kljub temu osredotočene zaradi njegove neodvisne študije, zlasti spisov Rudolfa Clausiusa o termodinamiki. Ko se je vrnil v München, je doktoriral julija 1879 (leto Einsteinovega rojstva) pri nenavadno mladi starosti 21 let. Naslednje leto je zaključil Habilitacija (kvalifikacijska disertacija) v Münchnu in postal a Privatdozent (predavatelj). Leta 1885 je bil s pomočjo očetovih poklicnih povezav imenovan ausserordentlicher profesor (izredni profesor) na Univerzi v Kielu. Leta 1889, po Kirchhoffovi smrti, je Planck dobil imenovanje na Univerzo v Berlinu, kjer je prišel častiti Helmholtza kot mentorja in sodelavca. Leta 1892 je bil povišan v ordentlicher profesor (redni profesor). Skupaj je imel le devet doktorskih študentov, vendar so njegova berlinska predavanja o vseh vejah teoretične fizike doživela številne izdaje in imela velik vpliv. V Berlinu je ostal do konca svojega aktivnega življenja.

Planck se je spomnil, da je bila njegova "prvotna odločitev, da se posvetim znanosti, neposreden rezultat odkritja ... da zakoni človeškega sklepanja sovpadajo z zakoni, ki urejajo zaporedje vtisov, ki jih o svetu dobimo od sveta, zato lahko čisto sklepanje omogočiti človeku vpogled v mehanizem [sveta] ... " Z drugimi besedami, namerno se je odločil, da postane teoretični fizik v času, ko teoretična fizika še ni bila priznana kot disciplina sama po sebi. Šel pa je še dlje: zaključil je, da obstoj fizikalnih zakonov predpostavlja, da je »zunanji svet nekaj neodvisnega od človeka, nekaj absolutnega in da se je iskanje zakonov, ki veljajo za ta absolut, pojavilo ... kot najbolj vzvišeno znanstveno prizadevanje v življenju. ”

Prvi primer absolutnega značaja, ki je Plancka močno navdušil, tudi kot a Gimnazija študent, je bil zakon ohranjanja energije, prvi zakon termodinamike. Kasneje, v letih univerze, je bil prav tako prepričan, da je zakon entropije, drugi zakon termodinamike, tudi absolutni naravni zakon. Drugi zakon je postal predmet njegove doktorske disertacije v Münchnu in je ležal v jedru raziskav, ki so ga pripeljale do odkritja kvantitacije delovanja, ki je zdaj znana kot Planckova konstanta h, leta 1900.

Kirchhoff je v letih 1859–60 definiral črno telo kot predmet, ki odseva vso sevalno energijo, ki pada nanj, torej kot popoln oddajnik in absorber sevanja. V sevanju črnega telesa je bilo torej nekaj absolutnega in do leta 1890 so bili izvedeni različni eksperimentalni in teoretični poskusi, da bi določili njegovo spektralno porazdelitev energije - krivuljo, ki prikazuje, koliko energije sevanja se oddaja pri različnih frekvencah za dano temperaturo črnega telesa. Plancka je še posebej pritegnila formula, ki jo je leta 1896 našel njegov kolega Wilhelm Wien na Physikalisch-Technische Reichsanstalt (PTR) v Berlinu-Charlottenburgu, nato pa je na podlagi drugega zakona naredil vrsto poskusov izpeljati "dunajski zakon" termodinamike. Do oktobra 1900 pa so drugi kolegi na PTR -ju, eksperimentatorji Otto Richard Lummer, Ernst Pringsheim, Heinrich Rubens in Ferdinand Kurlbaum, našli dokončne znake, da je Wienjev zakon, čeprav je veljal pri visokih frekvencah, popolnoma razpadel pri nizkih frekvencah.

Planck je za te rezultate izvedel tik pred sestankom Nemškega fizikalnega društva 19. oktobra. Vedel je, kako mora biti entropija sevanja matematično odvisna od njene energije v visokofrekvenčnem območju, če tam velja Wien zakon. Ugotovil je tudi, kakšna mora biti ta odvisnost v nizkofrekvenčnem območju, da bi lahko tam reproduciral eksperimentalne rezultate. Planck je torej ugibal, da bi moral ta dva izraza poskušati združiti na najpreprostejši možni način in rezultat pretvoriti v formulo, ki energijo sevanja povezuje s svojo frekvenco.

Rezultat, znan kot Planckov zakon sevanja, je bil nesporno pravilen. Za Plancka pa je bilo to samo ugibanje, "srečna intuicija". Če bi ga morali jemati resno, bi morali nekako izhajati iz prvih načel. To je bila naloga, na katero je Planck takoj usmeril svojo energijo in do 14. decembra 1900 mu je to uspelo - vendar z veliko ceno. Za dosego svojega cilja je Planck ugotovil, da se mora odreči enemu svojih najbolj cenjenih prepričanj, da je drugi zakon termodinamike absolutni naravni zakon. Namesto tega je moral sprejeti interpretacijo Ludwiga Boltzmanna, da je drugi zakon statistični zakon. Poleg tega je moral Planck domnevati, da oscilatorji, ki vsebujejo črno telo in ponovno oddajajo sevalno energijo, ki pada nanje, te energije ne morejo absorbirati neprekinjeno, ampak le v diskretnih količinah, v kvantih energije le s statistično porazdelitvijo teh kvantov, od katerih vsak vsebuje količino energije hν sorazmerno s svojo frekvenco, bi lahko Planck po vseh oscilatorjih, prisotnih v črnem telesu, izpeljal formulo, na katero je zadel dva meseca prej. Predložil je dodatne dokaze o pomembnosti svoje formule z uporabo za oceno konstante h (njegova vrednost je bila 6,55 × 10 −27 erg-sekunde, blizu sodobne vrednosti 6,626 × 10 -27 erg-sekunde), pa tudi tako imenovana Boltzmannova konstanta (temeljna konstanta v kinetični teoriji in statistični mehaniki), Avogadrova številka in naboj elektrona. Ko je čas tekel, so fiziki vse jasneje spoznali, da - ker Planckova konstanta ni bila nič, ampak je imela majhno, a končno vrednost - mikrofizikalnega sveta, sveta atomskih dimenzij, običajna klasična mehanika načeloma ni mogla opisati. Nastala je globoka revolucija v fizikalni teoriji.

Z drugimi besedami, Planckov koncept energijskih kvantov je bil v bistvu v nasprotju z vso preteklo fizikalno teorijo. Uvesti ga je moralo strogo po sili svoje logike, saj je bil, kot je rekel en zgodovinar, nejevoljen revolucionar. Dejansko so minila leta, preden so bile daljnosežne posledice Planckovega dosežka splošno priznane in pri tem je imel Einstein osrednjo vlogo. Leta 1905 je Einstein neodvisno od Planckovega dela trdil, da je v določenih okoliščinah sama sevalna energija sestavljena iz kvantov (svetlobni kvanti, pozneje imenovani fotoni), leta 1907 pa je pokazal splošnost kvantne hipoteze z uporabo za razlago temperaturne odvisnosti specifične toplote trdnih snovi. Leta 1909 je Einstein v fiziko uvedel dvojnost valovnih delcev. Oktobra 1911 sta bila Planck in Einstein med skupino uglednih fizikov, ki sta se udeležila prve Solvayeve konference v Bruslju. Tamkajšnje razprave so Henrija Poincaréja spodbudile k matematičnemu dokazu, da je Planckov zakon sevanja nujno zahteval uvedbo kvantov - dokaz, ki je Jamesa Jeansa in druge spremenil v podpornike kvantne teorije. Leta 1913 je k kvantitativni teoriji vodikovega atoma veliko prispeval tudi Niels Bohr. Ironično je, da se je sam Planck med zadnjimi boril za vrnitev v klasično teorijo, kar je pozneje obravnaval ne z obžalovanjem, ampak kot sredstvo, s katerim se je temeljito prepričal o nujnosti kvantne teorije. Nasprotovanje Einsteinovi radikalni svetlobni kvantni hipotezi iz leta 1905 je trajalo vse do odkritja Comptonovega učinka leta 1922.


Max Planck in problem sevanja črnega telesa

Toplotno sevanje

Prvi namig, da ima lahko sevanje tudi lastnosti, podobne delcem, je prišel leta 1900. Prišel je z očitno neškodljivim delom pri toplotnem sevanju. Tovrstno sevanje je znano vsem. To je sevanje, ki nam ogreje roke pred ognjem, zažge zdravico in poskrbi za intenzivno bleščanje peči. Fiziki so merili, koliko energije najdemo v vsaki od različnih frekvenc (tj. Barv), ki obsegajo toplotno sevanje. Ta porazdelitev se spreminja s temperaturo sevanja. Ker telo, ki oddaja sevanje, prehaja iz rdeče v oranžno v belo toploto, se frekvence z največjo energijo ustrezno spreminjajo.

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Leta 1900, ko so prišli najnovejši in najnovejši podatki, je Max Planck v Berlinu delal na razumevanju fizikalnih procesov, ki so privedli do teh porazdelitev energije. Dobro se je zavedal zadnjih rezultatov svojih berlinskih kolegov, Lummerja in Pringsheima, in da nobena sedanja teorija ne ustreza njihovim najnovejšim eksperimentalnim podatkom. Oblikoval je nov račun, ki se je zelo dobro prilegal. Po njegovem mnenju je toplotno sevanje skupek številnih frekvenc elektromagnetnih valov, ki so prišli do ravnovesja v votlini. Valovi se absorbirajo in oddajajo z nihajočimi naboji v stenah votline. Na ta način lahko temperaturo sten prenesemo na samo sevanje. Vdolbina je res samo pečica in zapolnjuje prostor v notranjosti s toplotnim sevanjem. To sevanje v votlini je bilo znano kot "sevanje votline".

Če bi odprli majhno okno v stenah votline, bi sproščeno sevanje imelo tudi temperaturo votline. Nekateri pametni termodinamični argumenti so pokazali, da ima popolnoma enako sestavo kot sevanje, ki ga pri isti temperaturi ponovno oddaja telo, če ima to telo posebno lastnost, da popolnoma absorbira vse sevanje, ki je padlo nanj, preden ga je ponovno sevalo. Takšna telesa se imenujejo "črna", zato je oblika sevanja znana kot "sevanje črnega telesa".

Planckova analiza iz leta 1900

Planck je našel zelo preprosto formulo, ki je zelo ustrezala najnovejšim eksperimentalnim rezultatom. Njegov problem je bil povedati teoretično zgodbo o nastanku te formule. Po nekaj obotavljanju je našel takšno zgodbo. Vendar je bil bistveni izračun v njegovi zgodbi odvisen od zelo čudne predpostavke. (Danes se nadaljuje razprava o tem, ali je Planck dejansko spoznal, kako radikalna je bila ta predpostavka in kako pomembna je bila za njegov račun.) Planck je modeliral toplotno sevanje, ki prihaja iz električnih resonatorjev pod napetostjo.

Navadni resonatorji klasične fizike so le mase, ki vibrirajo na vzmeti, kot je prikazano na sliki. Lahko prevzamejo stalen razpon energije.

Planckova zgodba je zahtevala, da se ti resonatorji ne napajajo v neprekinjenem razponu energij. Namesto tega bi lahko vzeli energijo, recimo, 0, 1, 2, 3,. enote, vendar nič vmes . Prepovedana je bila energija, recimo 1,2 enote ali 3,7 enote.

Odločitev, katere enote so se izkazale za pomembne. Enote energije so bile vezane na resonančno frekvenco resonatorja. Podane so bile po Planckovi formuli:

To pomeni, da so dovoljene energije (h x frekvenca), dvakrat (h x frekvenca), trikrat (h x frekvenca) itd.

Črka h pomeni novo konstanto narave, ki jo je uvedel Planck in se zdaj imenuje "Planckova konstanta". Ta nova konstanta ima v kvantni teoriji enako vlogo, kot jo ima v teoriji relativnosti hitrost svetlobe in nam pove, kdaj bodo kvantni učinki pomembni. Število je zelo majhno, kar kaže na to, da je treba pri majhnih pričakovati kvantne učinke, na primer za navadne frekvence bodo enote energije, podane po Planckovi formuli, zelo majhne, ​​zato ne bomo opazili zrnatosti, ki jo potrebuje, ko pogledamo večje energije sistemov navadne izkušnje. (h = 6,62 x 10 -27 erg sekund.)

Planckova izvirna formula je veljala za energijo resonatorjev. Zelo se je trudil omejiti diskontinuiteto, ki jo je predlagala tem resonatorjem, in celo samo interakcijo med sevanjem in resonatorji. V naslednjem desetletju so drugi fiziki začeli ugotavljati, da diskontinuitete ni mogoče omejiti. Izračune, podobne Planckovim iz leta 1900, bi lahko uporabili neposredno za sevanje toplote. Prišli so do zaključka, da Planckova formula velja tudi za toplotno sevanje. Pri vsaki frekvenci mora energija toplotnega sevanja prihajati v cele enote h x frekvence. Tega sklepa je težko uskladiti z idejo, da je toplotno sevanje zgolj valovni pojav.


4 odgovori 4

"Čisto stanje je kvantno stanje, kjer imamo natančne informacije o kvantnem sistemu. Mešano stanje pa je kombinacija verjetnosti informacij o kvantnem stanju. Različne porazdelitve čistih stanj lahko ustvarijo enakovredna mešana stanja. Nisem razumel kako lahko kombinacija natančnih informacij povzroči kombinacijo verjetnosti. "

Na Blochovi krogli so čista stanja predstavljena s točko na površini krogle, mešana stanja pa z notranjo točko. Popolnoma mešano stanje posameznega kubita $ << frac <1> <2>> I_ <2> ,> $ predstavlja središče krogle s simetrijo. Čistost stanja si lahko predstavljamo kot stopnjo, v kateri je blizu površine krogle.

V kvantni mehaniki je stanje kvantnega sistema predstavljeno z vektorjem stanja (ali ketom) $ | psi rangle $. Kvantni sistem z vektorjem stanja $ | psi rangle $ se imenuje čisto stanje. Možno pa je tudi, da je sistem v statistični zbirki različnih vektorjev stanja: na primer obstaja 50 -odstotna verjetnost, da je vektor stanja $ | psi_1 rangle $ in 50% možnost, da je vektor stanja $ | psi_2 rangle $.

Ta sistem bi bil v mešanem stanju. Matrika gostote je še posebej uporabna za mešana stanja, saj lahko vsako stanje, čisto ali mešano, označimo z eno samo matriko gostote.

Vektor stanja $ | psi rangle $ čistega stanja v celoti določa statistično obnašanje meritve. Za konkretnost vzemimo opazljivo količino in naj bo A pridruženi opazovalni operater, ki ima predstavitev v Hilbertovem prostoru $ < mathcal > $ kvantnega sistema. Za vsako analitično funkcijo $ F $, ki je definirana na realnih številkah, predpostavimo, da je $ F (A) $ rezultat uporabe $ F $ za izid merjenja. Pričakovana vrednost $ F (A) $ je

$ langle psi | F (A) | psi rangle ,. $

Zdaj pa razmislite o mešanem stanju, pripravljenem s statistično kombinacijo dveh različnih čistih stanj $ | psi rangle $ in $ | phi rangle $, s pripadajočimi verjetnostmi $ p $ in $ 1 - p $. Povezane verjetnosti pomenijo, da se postopek priprave kvantnega sistema konča v stanju $ | psi rangle $ z verjetnostjo $ p $ in v stanju $ | phi rangle $ z verjetnostjo $ 1 - p $.


Ali so kvantna nihanja ustvarila vesolje?

Glede na razpravo, ki jo je sprožila najnovejša knjiga Stephena Hawkinga#8217, bi nekateri naši bralci našli odgovor, ki ga je profesor Edgar Andrews objavil v temi za razpravo Amazon.co.uk, uporaben:

“ Nihče ni naredil evolucije. Pojavlja se kot naravna in neizogibna posledica zakonov narave v vesolju, v katerem se nahajamo, ki so sami po sebi naravna in neizogibna posledica popolnoma naključnega kvantnega nihanja, ki je povzročilo veliki pok, nakar “ zakoni &# 8221 vzročne zveze se razčleni, zato je nesmiselno spraševati, kdo ali kaj je to povzročilo. ”

“Toda to se res ne opere, kajne? V istem sapu pravite, da so veliki pok povzročili kvantna nihanja, nato pa trdite, da je nesmiselno spraševati, kaj je povzročilo veliki pok. Morda je to postmodernizem, vendar zagotovo ni logika (ali fizika). Toda pri vaših razlagah obstajajo še globlje napake:

1) Naravni zakoni, praviš, so "posledice, ki jih ni mogoče", in#8221 “ popolnoma naključnih kvantnih nihanj ”. Po kakšni logiki lahko iz naključnih dogodkov nastanejo neizogibne posledice? Naključni dogodki lahko vodijo le do pogojnih posledic, vendar pa posledice ne morejo biti pogojne, ampak jih je treba določiti (potrebno).

2) Da bi bili naravni zakoni "posledica" česar koli, mora delovati načelo vzročnosti. Brez vzročnosti ne more biti ne vzrokov ne posledic. Potem pa nam poveš, da se po velikem poku zakoni vzročnosti porušijo. Res ne morete imeti obojega.

3) Pravite, da je veliki pok povzročil “naključna kvantna nihanja ”. Razen tega, da okrepim svojo zadnjo točko s sklicevanjem na vzročnost pred obstojem vesolja, morate odgovoriti na drugo vprašanje in#8230 nihanja v čem? Pred velikim pokom ni obstajala ne snov, ne energija, ne prostor ne čas, zato po definiciji v nobeni od teh entitet ni moglo biti nihanj. (Če trdite, da je bilo pred velikim pokom nekaj materialne narave “ tam ”, ne govorimo več o končnem izvoru vesolja).

3) Sledi še eno vprašanje. Ali niso kvantna nihanja sama po sebi manifestacija naravnega zakona (npr. Zakoni kvantne mehanike)? Kako bi lahko bila kvantna nihanja končni vzrok naravnega prava, kot trdite? Ali so si zakoni, ki urejajo kvantno nihanje, sami izmislili? Tega ne verjame niti Stephen Hawking. ” [/pk_box]

Edgar Andrews, zaslužni profesor materialov na Univerzi v Londonu in avtor odlične knjige, Kdo je naredil Boga? Iskanje teorije vsega. Kdo je naredil Boga? je na voljo v knjigarnah Amazon in Nova Zelandija (Grace & amp Truth Publications ima na voljo kopije za 24 USD).

Deliti to:

Delite ta vnos

Jaz ’v sem vedno dvomil v teorijo velikega poka. Zame je vesolje neskončno, saj je energija neskončna in vesolje je zgolj energija, vse, kar je nastalo iz energije, in energije ni mogoče izgubiti samo z informacijami v energiji, glej nedavni razvoj raziskav črnih lukenj, kjer so dokazali to, tako preprosto, res, vesolje vedno ni bilo tako, kot ga poznamo. Pomisliti, da ni bilo ničesar, potem pa nenadoma razbiti vesolje, je tako smešno kot zamisel o stvarjenju kristjanov. Pomislite na ta način: črne luknje izsesajo energijo iz vesolja, sonca ali bele luknje, ki so ravno nasprotje črne luknje, vržejo energijo nazaj v vesolje in informacije o energiji se v tem procesu spremenijo . Ne morete ’t ustvariti več energije ali izčrpati energijo, lahko le pretvorite energijo … .. Resnična neskončnost.

Energija ni neskončna. Kjer ste odkrili, da to ni, ni mogel biti ugleden vir. Verjetno ste napačno razumeli, kaj berete. Energija je skupaj z vesoljem začela obstajati po napovedih standardnega modela velikega poka.

Pravite, “ Misliti, da ni bilo nič in potem nenadoma razbiti vesolje, je tako smešno kot zamisel o ustvarjanju krščanstva. ”
No, nič potem BANG, vesolje, ni smešno, se strinjam. Nič ne nastane iz nič, kot pravijo filozofi. Toda to ni tako smešno kot krščanska zamisel o stvarstvu. Krščanska ideja ustvarjanja pripisuje vzrok vesolja Bogu. Krščanski pogled se ujema s filozofsko maksimo, kajti po tem pogledu je nekaj (vesolje) prišlo iz nečesa (Boga), ne pa, da je nekaj nastalo iz nič.

Ali ’t ohranitev energetskega zakona v fiziki ne pravi, da je energije mogoče ’t ustvariti ali uničiti, le spremeniti v različne oblike energije, kot je načelo pretvorbe mase/snovi s snovjo? Če tako energije kot snovi v zaprtem sistemu (Vesolje bi se lahko štelo za zaprt sistem, kot je tisto, kar je zunaj kozmološkega obzorja Velikega poka,) ni mogoče ustvariti ali uničiti, preprosto spremeniti v različne oblike snovi in ​​energije, če ostanejo konstantni v tem zaprtem sistemu vesolja, v katerem živimo, kot narekujejo zakoni fizike, ali ne bi bilo logično misliti, da je vsa ta masa in energija, ki obsega naše vesolje, VEDNO obstajala?

Veliki pok navaja, da je bilo vesolje nekoč singularnost, saj je to tako daleč, kolikor lahko gremo zaradi zakonov fizike, kot jih poznamo, da se popolnoma razgradijo, nato pa se od tam razširijo. Mogoče je vsa snov in energija v vesolju obstajala v tej edinstvenosti in je obstajala že od nekdaj, ni potreben ustvarjalec ali bog? Mogoče morajo zakoni fizike zaspati, kot mislimo, da to počnejo v singularnostih, da kvantna nihanja opravijo svoje delo?

Janez, tvoja trditev ima več nepremostljivih težav. Prvič, ne morete pojasniti prvotnega vprašanja, ki že desetletja muči Hawkinga in druge teoretične fizike: Zakaj nekaj namesto nič? Ne glede na velikost “dimenzije ” vaše posebnosti (v vsakem smislu relativno) jo je treba upoštevati. Drugič, upoštevajte pogoje, ki so privedli do “instabilnosti ” singularnosti, ki je povzročila začetno rast (hiper inflacija). Zakaj bi sedeli v mirovanju večnost, potem pa se korenito spremeni. Od kod zagon? Sprememba stanja zahteva vzročnost. Prav tako je verjetnost kvantnih dogodkov neposredno sorazmerna s časovnimi intervali. Z zmanjšanjem časa se verjetnost zmanjšuje. Za dogodek singularnosti trenutka “kreacije ” je čas = nič, zato je verjetnost = nič. Ni razloga, da bi zakon vzroka in posledice zanikali zgolj zato, ker je teološko ali filozofsko neprijeten. Additionally the existence of information and intelligence mandates a prior intelligence to the formation of the universe, it is inescapable. If we were to approach any other discipline, such as forensics or engineering, with the same degree of closed-mindedness of pure naturalism, we would of necessity arrive at ludicrous and illogical conclusions.

The laws of thermodynamics (and specifically, the first law you mentioned that states energy cannot be created or destroyed) only applies once the universe is created – not before there is a universe. It only aplies within the universe – not on the universe. So there’s no contradiction here with the science of thermodynamics and the idea that the universe began to exist.

You make some interesting points of course. However, The Big Bang as a cosmological Theory is still relatively incomplete. I was simply postulating a possibility, that matter and energy, and by necessity our universe, in one state or another is eternal. I will say it truthfully, I can’t account for what caused hyper inflation to begin with, there are a couple of ideas out there, like i said with quantum fluctuations being a possible source, but of course modern science cant push our theoretical framework passed the Planck scale, because once you go passed that, everything breaks down, including the laws of thermodynamics I believe, Stuart.

However Ktisis, you then go on to say that information and intelligence existing as part of this universe must necessitate a prior intelligence. You are making this claim on what grounds? Why is it mandated that intelligence needs a source? Why isn’t it a by-product of evolution? No where in science does it say we know how the universe started, because we dont know, we have theories, ideas of how it might have happened, based on measurable phenomenon we are currently able to observe, but no concrete ” Yeah, this is how it went down”. When you say God did it, the burden of proof is on you.

Apply Occam’s Razor then – What is simplest? God did it, which of course brings to mind all kinds of stuff like, if God created the universe, who created God?

Or the universe has always existed, in one state or another? We can see the universe, we can test the universe. Theres all kinds of matter and energy, abundunt everywhere, but no proof, no testable effect, of God having done it.

I’d like to ask before hand you guys disregard the general anti-religious flavor of the above video, as it is hosted by Richard Dawkins. It’s a presentation by Lawrence Krauss (also an atheist, forgive him his Religious snide commentary) on the possibility of the beggining of the universe. It’s interesting to watch, if you love science.

I’d also like to say that I myself am not an atheist, i honestly couldn’t categorize, as I neither believe in any of the dominant religions of our day and age, nor hold any particular atheistic views, I guess I’m agnostic. However, I find some of the anti-religious rhetoric that comes from people like Dawkins a tad distasteful, so I simply ask for a little forgiveness.

Actually you can test Theism as a hypothesis. For instance, If God (as concieved by Christians) exists, then the universe had a beginning.

Your theory that matter and energy are eternal will not work. Two philosophical proofs, (1) from the impossibilty of an acutal infinite, and (2) from the impossibilty of reaching an actual infinite by a series of equal successions, rule this out. Otherwise, there are scientific proofs that the universe is not eternal in the past. (3) The second law of Thermodynamics, the law of energy conservation indicates that the universe is not eternal in the past, and (4) the predictions of the Standard Big Bang Model. Here you say the theoretical framework cannot be extended beyong the planck time. Thats wrong. It is observation that cannot be extended beyond the planck time, not the theory. Only the breifest glance at the history of 20th century cosmogonies is enough to show this. However, due to the lengthy procession of failed theories that have sought to divert the absolute beginning of the universe predicted by the Standard Model and extend its life into the infinite past, we have good reason to think that future attempts will also be unsuccessful. Secondly, the Bord Guth Vilenkin theorum (c. 2004) positively proves that the universe had a beginning, by showing that any universe that has been in a state of cosmic inflation cannot be extended into the infinite past, but had an absolute beginning.

So given the universe had a beginning (premise 2, KCA), and that nothing can come from nothing (premise 1, KCA), applying Occam’s Razoris not detrimental to the conclusion of the KCA, nor Theism since we are ‘not positing anything beyond necessity.’ Thats Occam’s Razor. Occam’s Razor is not whatever explanation is simplest. And for whatever its worth, God as the cause of the universe is an advance in simplicity anyway, since God is simple compared to the effect – the complex material universe. God is an immaterial mind – tremendously simple entity (even if God did have a cause).

Sure you can hypothesize with theism to your heart’s content, but there is no empirical data, no measurable effect to prove your hypothesis. What do you use as empirical data to prove God? I’m not even referring to any particular one, for sake of argument, we will list God as the being who created the universe, hypothetically

Also, you say you cant get something from nothing, which is of course correct. The problem is, there is no such thing as “Nothing” The Quantum Vacuum as shown in the Casimir Effect shows this. Even in Vacuum there are quantum fluctuations, with virtual particles popping in and out of existence.

Also, you keep mentioning the law of thermal dynamics, but physical laws as we know them break down at the singularity and no longer apply, hence why observation doesn’t extend past the Planck scale of the cosmological singularity predicted in the Standard Model, because the laws and rules of the universe that we use for most science dont apply at the singularity, they don’t do what they are supposed to.

The thing is, we have no clue what happened prior to the Big Bang. The difference is, you claim that at the beggining it was God that set the ball rolling. Where is the Proof? There isn’t any. I was just theorizing, and of course, as you pointed out, there are many reasons for my theory to not be correct. The theistic Idea however, has no evidence to support it whatsoever, It’s totally in the domain of philosophy.

Saying the universe has a begining is not the same as saying it came from nothing.. It simply suggests that there is something external. It doesn’t have to be a God.

the fact is nobody knows. Saying God did it explains nothing.

Hey what happened to my previous post

Censorship isn’t fair in a debate guys

Also, The BGV theorem has this to say, quoted directly from the paper

Many inflating spacetimes are likely to violate the weak energy condition, a key assumption of singularity theorems. Here we offer a simple kinematical argument, requiring no energy condition, that a cosmological model which is inflating — or just expanding sufficiently fast — must be incomplete in null and timelike past directions. Specifically, we obtain a bound on the integral of the Hubble parameter over a past-directed timelike or null geodesic. Thus inflationary models require physics other than inflation to describe the past boundary of the inflating region of spacetime.
……
and later

Whatever the possibilities for the boundary, it is clear
that unless the averaged expansion condition can somehow
be avoided for all past-directed geodesics, inflation
alone is not sufficient to provide a complete description of
the Universe, and some new physics is necessary in order
to determine the correct conditions at the boundary

“inflation alone is not sufficient to provide a complete description of
the Universe, and some new physics is necessary in order
to determine the correct conditions at the boundary”

It doesn’t say anything about God, Just that there is some kind of new physics that we are not aware of that would be responsible.
Your twisting that paper to suit your preconceptions Stuart. You’re inserting “God” As the new physics. Youre combining philosophy and science., not a very logical thing to do.

You also make some other wild assumptions that have no basis in fact.
“God is an immaterial Mind” What do you base this off? Where is your empirical evidence of this?
“God is Simple ” Once again, evidence? Where is your evidence?
The existence of God as the cause immediatley leads to infinite regression, as if God is the cause of the universe what is the cause of god? Thats complex, not simple.

John, it doesn’t really reflect well on you when you jump to the conclusion that your comment wasn’t immediately published because of “censorship”.

Our comment filter is fairly stringent to avoid spam, which we get a lot of. So most comments have to be manually approved. And believe it or not, we don’t sit in the WordPress dashboard all day hitting the Refresh button P

There is a major philosophical problem with your above comments. I will freely admit there is no purely empirical evidence for God. However, empirical evidence can be used to support a premise, which when combined with philosophical notions in other premises can lead toward a logical conclusion. You say comining philosophy and science is illogical? No. This method describes the process of forming every other reasonable belief, including scientific beliefs formed by responsible empirical enquiry.

For instance, one could say, there is a creature out there with certain attributes, say for instance it has wings, can swim as well as a fish, the male sits on the eggs to keep it warm, it can grow as tall as 100cm. We can be skeptical about it, because its doesn’t sound like anything we’ve ever seen or experienced. But when we hear about the emperor penguin, (perhaps you saw it for yourself, perhaps you read about it, or heard it described on the BBC by David Attinborough) you say to youself, ‘Hey, this fits the description.’ Then we combine this empirical evidence a philosophical assumption (hidden premise), i.e. “The report I am recieving from my senses is trustworthy,” and/or “This creature is not logically impossible,” and/or ” Likewise, Attinborough would not make this up, but he and his crew would have a direct and immediate sensory impression.” We then can conclude justifiably ‘My hypothesis [of such a creture with certain attributes] was right after all.’ Likewise, we have a concept of God as having certain attributes, we know from the KCA that the universe has a cause, and then when we consider what it would mean for something to be a cause of the universe, then we can say, ‘Hey, this fits the description of such a being.’

This is like Aquinas saying, ‘And this being, everyone calls God.’ What properties does the “something external [to the universe]” have, do you think? Now doesn’t such a description fit the concept of God quite nicely? And what are you going to call it? This being/cause/whatever, afterall, created the universe.

I agree there is no such THING as nothing. After all, thats the meaning of nothing – No-thing. Some people call the vacuum “nothing” but it is clearly not nothing. It is something, endowed and governed by physical laws. The universe however began from nothing in the sense of creatio ex nihilo, No-thing.

This is the prediction of the Standard Big Bang Model. Other models that have tried to extend the universe into the infinite past have continually failed to recommend themselves to the scietific community, and because of the Bord Guth Vilenkin theorem, cannot be infinite in the past since the theorem is independant of a physical description of the past universe. It was Alan Guth, I believe, who said, “With the proof now in, cosmologists must now face the problem of an absolute beginning.”

I’m not inserting God here as the new physics! I’m using the Bord Guth Vilenkin theorem as support for the beginning of the universe.

“God is an immaterial mind.” I base this off the revealed and traditional concept of God. But is there another reason why the creator or cause of the universe would be an immaterial mind. Since the universe is all that is material, the cause of the universe must be immaterial. Since the only immaterial things that philsophers are aware of are minds and abstract objects, and since abstract objects cannot cause anything, then the cause of the unvierse must be a mind. Thus, the cause of the universe must be an immaterial mind. God is an immaterial mind. And an immaterial mind is tremendously simple. It cannot be divided since it has not physical parts – it has no components to put together.

“The existence of God as the cause immediatley leads to infinite regression, as if God is the cause of the universe what is the cause of god? Thats complex, not simple.”

If God had a cause that wouldn’t mean he was complex. But what is your problem with infinite regressions anyway? Its an eternal universe that je an infinite regression, which based on your above comments above, you don’t have a problem with. A major inconsistancy in your arguments here.

And why would you think that a being that bought time into existence with the universe, itself began to exist? This is your burden if you’re to advance this argument. It is unfortunately for those who advance the argument immediately apparent the very question is ridiculous. The cause of the universe (all space and time) must be timeless, thus be beginningless and unchanging. That which is beginningless and unchanging is necessary: the universe is contingent (it didn’t have to exist) – the cause of the unverse must be not-contingent, i.e. necessary (it had to exitst). So the question “Who made God?” is therefore exactly “What was the cause of an uncaused cause?” Analogously, it is like the question “What is the name of the bachelor’s wife?” or like saying “The area of the circle is the square of both its sides.” It’s idiotic. Res! Why people think its profound is beyond me.

Refer to the website address at http://en.wikipedia.org/wiki/Dark_energy pertaining to dark energy.

The following is the extract of the second paragraph under the sub-title of “Negative Pressure” for the main subject of the ‘Nature Of Dark Energy’:

According to General Relativity, the pressure within a substance contributes to its gravitational attraction for other things just as its mass density does. This happens because the physical quantity that causes matter to generate gravitational effects is the Stress-energy tensor, which contains both the energy (or matter) density of a substance and its pressure and viscosity.

As the phrase, the physical quantity that causes matter to generate gravitational effects is mentioned in the extracted paragraph, it gives the implication that physical quantity of matter has to exist prior to the generation of gravitational effects. Or in other words, it opposes the principality that gravitational effects could occur at the absence of matter. As it is described pertaining to Dark Energy, it implies that Dark Energy could only be derived from the existence of the physical quantity of matter. This certainly rejects Stephen Hawking’s theory in which dark energy could exist prior to the formation of the universe as if that dark energy could exist the support or influence from the physical quantity of matter.

The following is the extract of the third paragraph under the sub-title of ‘Cosmological Constant’ for the main subject of the ‘Nature of Dark Energy’:

The simplest explanation for dark energy is that it is simply the “cost of having space”: that is, a volume of space has some intrinsic, fundamental energy. This is the cosmological constant, sometimes called Lambda (hence Lambda-CDM model) after the Greek letter ?, the symbol used to mathematically represent this quantity. Since energy and mass are related by E = mc2, Einstein’s theory of general relativity predicts that it will have a gravitational effect..

E = mc2 has been used to be related to Dark Energy. As energy and mass are related in according to General Relativity and if m = 0, no matter how big the number that c could be, E (the dark energy) would turn up to be 0 since 0 is multiplied by c2 always equal to 0. Or in other words, E (the dark energy) should be equal to 0 at the absence of substance. Stephen Hawking’s theory certainly contradicts Eistein’s theory in the sense that he supports that dark energy could exist even though there could not be any matter existed prior to the formation of the universe. As E (the dark energy should be equal to 0) when m=0, it provides the proof that there would not be at dark energy prior to the formation of the universe. As there would not be any dark energy prior to the formation of the universe, how could Stephen Hawking uses quantum theory to support that gravity or the so-called, dark energy, could create something out of nothing. Thus, Stephen Hawking has twisted Eistein’s theory to support his own theory.

Refer to the website address at: http://csep10.phys.utk.edu/astr161/lect/history/newtongrav.html pertaining to the law of universal gravitation. The following is the extract of the definition of law of universal gravitation:

Every object in the universe attracts every other object with a force directed along the time of centers for the two objects that is proportional to the product of their masses and inversely separation between the two objects. Fg = G(m1 m2)//r2. (Fg is the gravitational force m1 & m2 are the masses of the two objects r is the separation between the objects and G is the universal gravitational constant. From the formula, we note that Fg (the gravitational force or in replacement of dark energy) has a direct influence from two masses (m1 & m2). If either of the m is equal to 0, Fg would turn up to be 0. Isaac Newton’s theory certainly opposes Stephen Hawking in which gravity or the so-called, dark energy, could exist at the absence of matter prior to the formation of this universe in this energy or gravity could create something out of nothing.

From the above analyses, it would come to the conclusion that Stephen Hawking has twisted both Newton’s theory as well as Eistein to support his quantum theory in which gravity, or the so-called, dark energy, could create something out of nothing.

As Stephen Hawking has twisted both Newton’s gravitational theory and Eistein to support his theory that quantum fluctuation could create the universe, this gives us the idea that his theory contradicts sicence in realtiy and that put his theory to be in doubts about its reliability and acceptability.

Stephen Hawking might mention that both Newton’s gravitational theory and Eistein are wrong. As he was not born at the time of the formation of the universe to observe its creation, his theory is simply not tested and ithrough his wild imagination by twisting scientific theories to suit his concept.

Could we have some rebuttal from John for Stuart? The debate was going very nicely, and I would love to see how John would come back, and I’m sure Stuart would too!


The real history of quantum biology

Credit: CC0 Public Domain

Quantum biology, a young and increasingly popular science genre, isn't as new as many believe, with a complicated and somewhat dark history, explain the founders of the world's first quantum biology doctoral training centre.

In a paper published by the Royal Society journal, Proceedings of the Royal Society A, Professors Johnjoe McFadden and Jim Al-Khalili from the University of Surrey trace the origins of quantum biology as far back as the late 1920s when the Danish physicist, Niels Bohr, delivered an influential lecture on whether the then new 'atomic theory' could help solve the mystery of life.

In their paper, The origins of quantum biology, McFadden and Al-Khalili examine nearly 100 years of pioneering and improbable questions about the relationship between the fuzzy and almost magical world of quantum physics and the rigid and organised field of biology.

Quantum biology seeks to understand whether quantum mechanics plays a role in biological processes. Recent research has already shown phenomena such as photosynthesis, respiration, bird navigation and even the way we think are all influenced by quantum mechanics.

Earlier this year, Professors McFadden and Al-Khalili opened the doors to their new Doctoral Training Centre for Quantum Biology. The centre, which is supported by the Leverhulme Trust, trains a new generation of scientists who can operate across the boundaries of biology, chemistry and quantum physics to pioneer research in quantum biology.

Johnjoe McFadden, Professor of Molecular Genetics and Co-Director of the Centre for Quantum Biology at the University of Surrey, said: "Quantum biology is wrongly regarded as a very new scientific discipline, when it actually began before the Second World War. Back then, a few quantum physicists tried to understand what was special about life itself and whether quantum mechanics might shed any light on the matter. In this paper we tell the story of how it all began and why it is only now making a comeback."

Jim Al-Khalili, Professor of Physics and Co-Director of the Centre for Quantum Biology at the University of Surrey, said: "With the University of Surrey now hosting the world's first doctoral training centre in quantum biology and training Ph.D. students in this interdisciplinary field, we felt it was a good time tell the world something about its origins.

"We had wanted to lay out the history of quantum biology as far back as 2015, when Johnjoe and I wrote our popular science book,Life on the Edge, which has already been translated into 16 languages and was shortlisted for the Royal Society Winton Book Prize."


Plum Pudding Model and Rutherford Model

JESPER KLAUSEN / SCIENCE PHOTO LIBRARY / Getty Images

Up to this point, atoms were believed to be the smallest units of matter. In 1897, J.J. Thomson discovered the electron. He believed atoms could be divided. Because the electron carried a negative charge, he proposed a plum pudding model of the atom, in which electrons were embedded in a mass of positive charge to yield an electrically neutral atom.

Ernest Rutherford, one of Thomson's students, disproved the plum pudding model in 1909. Rutherford found that the positive charge of an atom and most of its mass were at the center, or nucleus, of an atom. He described a planetary model in which electrons orbited a small, positive-charged nucleus.


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Origin and education Edit

Louis de Broglie belonged to the famous aristocratic family of Broglie, whose representatives for several centuries occupied important military and political posts in France. The father of the future physicist, Louis-Alphonse-Victor, 5th duc de Broglie, was married to Pauline d’Armaille, the granddaughter of the Napoleonic General Philippe Paul, comte de Ségur. They had five children in addition to Louis, these are: Albertina (1872–1946), subsequently the Marquise de Luppé Maurice (1875–1960), subsequently a famous experimental physicist Philip (1881–1890), who died two years before the birth of Louis, and Pauline, Comtesse de Pange (1888–1972), subsequently a famous writer. [13] Louis was born in Dieppe, Seine-Maritime. As the youngest child in the family, Louis grew up in relative loneliness, read a lot, was fond of history, especially political. From early childhood, he had a good memory and could accurately read an excerpt from a theatrical production or give a complete list of ministers of the Third Republic of France. For him was predicted a great future as a statesman. [14]

De Broglie had intended a career in humanities, and received his first degree in history. Afterwards he turned his attention toward mathematics and physics and received a degree in physics. With the outbreak of the First World War in 1914, he offered his services to the army in the development of radio communications.

Military service Edit

After graduation, Louis de Broglie as a simple sapper joined the engineering forces to undergo compulsory service. It began at Fort Mont Valérien, but soon, on the initiative of his brother, he was seconded to the Wireless Communications Service and worked on the Eiffel Tower, where the radio transmitter was located. Louis de Broglie remained in military service throughout the First World War, dealing with purely technical issues. In particular, together with Léon Brillouin and brother Maurice, he participated in establishing wireless communications with submarines. Prince Louis was demobilized in August 1919 with the rank of adjudant. Later, the scientist regretted that he had to spend about six years away from the fundamental problems of science that interested him. [14] [15]

Scientific and pedagogical career Edit

His 1924 thesis Recherches sur la théorie des quanta [16] (Research on the Theory of the Quanta) introduced his theory of electron waves. This included the wave–particle duality theory of matter, based on the work of Max Planck and Albert Einstein on light. This research culminated in the de Broglie hypothesis stating that any moving particle or object had an associated wave. De Broglie thus created a new field in physics, the mécanique ondulatoire, or wave mechanics, uniting the physics of energy (wave) and matter (particle). For this he won the Nobel Prize in Physics in 1929.

In his later career, de Broglie worked to develop a causal explanation of wave mechanics, in opposition to the wholly probabilistic models which dominate quantum mechanical theory it was refined by David Bohm in the 1950s. The theory has since been known as the De Broglie–Bohm theory.

In addition to strictly scientific work, de Broglie thought and wrote about the philosophy of science, including the value of modern scientific discoveries.

De Broglie became a member of the Académie des sciences in 1933, and was the academy's perpetual secretary from 1942. He was asked to join Le Conseil de l'Union Catholique des Scientifiques Francais, but declined because he was non-religious. [17] [18] On 12 October 1944, he was elected to the Académie Française, replacing mathematician Émile Picard. Because of the deaths and imprisonments of Académie members during the occupation and other effects of the war, the Académie was unable to meet the quorum of twenty members for his election due to the exceptional circumstances, however, his unanimous election by the seventeen members present was accepted. In an event unique in the history of the Académie, he was received as a member by his own brother Maurice, who had been elected in 1934. UNESCO awarded him the first Kalinga Prize in 1952 for his work in popularizing scientific knowledge, and he was elected a Foreign Member of the Royal Society on 23 April 1953.

Louis became the 7th duc de Broglie in 1960 upon the death without heir of his elder brother, Maurice, 6th duc de Broglie, also a physicist.

In 1961, he received the title of Knight of the Grand Cross in the Légion d'honneur. De Broglie was awarded a post as counselor to the French High Commission of Atomic Energy in 1945 for his efforts to bring industry and science closer together. He established a center for applied mechanics at the Henri Poincaré Institute, where research into optics, cybernetics, and atomic energy were carried out. He inspired the formation of the International Academy of Quantum Molecular Science and was an early member. [19] His funeral was held 23 March 1987 at the Church of Saint-Pierre-de-Neuilly. [20]

Louis never married. When he died in Louveciennes, [6] he was succeeded as duke by a distant cousin, Victor-François, 8th duc de Broglie.

Physics of X-ray and photoelectric effect Edit

The first works of Louis de Broglie (early 1920s) were performed in the laboratory of his older brother Maurice and dealt with the features of the photoelectric effect and the properties of x-rays. These publications examined the absorption of X-rays and described this phenomenon using the Bohr theory, applied quantum principles to the interpretation of photoelectron spectra, and gave a systematic classification of X-ray spectra. [14] The studies of X-ray spectra were important for elucidating the structure of the internal electron shells of atoms (optical spectra are determined by the outer shells). Thus, the results of experiments conducted together with Alexandre Dauvillier, revealed the shortcomings of the existing schemes for the distribution of electrons in atoms these difficulties were eliminated by Edmund Stoner. [21] Another result was the elucidation of the insufficiency of the Sommerfeld formula for determining the position of lines in X-ray spectra this discrepancy was eliminated after the discovery of the electron spin. In 1925 and 1926, Leningrad physicist Orest Khvolson nominated the de Broglie brothers for the Nobel Prize for their work in the field of X-rays. [13]

Matter and wave–particle duality Edit

Studying the nature of X-ray radiation and discussing its properties with his brother Maurice, who considered these rays to be some kind of combination of waves and particles, contributed to Louis de Broglie's awareness of the need to build a theory linking particle and wave representations. In addition, he was familiar with the works (1919–1922) of Marcel Brillouin, which proposed a hydrodynamic model of an atom and attempted to relate it to the results of Bohr's theory. The starting point in the work of Louis de Broglie was the idea of A. Einstein about the quanta of light. In his first article on this subject, published in 1922, the French scientist considered blackbody radiation as a gas of light quanta and, using classical statistical mechanics, derived the Wien radiation law in the framework of such a representation. In his next publication, he tried to reconcile the concept of light quanta with the phenomena of interference and diffraction and came to the conclusion that it was necessary to associate a certain periodicity with quanta. In this case, light quanta were interpreted by him as relativistic particles of very small mass. [22]

It remained to extend the wave considerations to any massive particles, and in the summer of 1923 a decisive breakthrough occurred. De Broglie outlined his ideas in a short note "Waves and quanta" (French: Ondes et quanta, presented at a meeting of the Paris Academy of Sciences on September 10, 1923), which marked the beginning of the creation of wave mechanics. In this paper, the scientist suggested that a moving particle with energy E and velocity v is characterized by some internal periodic process with a frequency E / h , where h is Planck's constant. To reconcile these considerations, based on the quantum principle, with the ideas of special relativity, de Broglie was forced to associate a "fictitious wave" with a moving body, which propagates with the velocity c 2 / v /v> . Such a wave, which later received the name phase, or de Broglie wave, in the process of body movement remains in phase with the internal periodic process. Having then examined the motion of an electron in a closed orbit, the scientist showed that the requirement for phase matching directly leads to the quantum Bohr-Sommerfeld condition, that is, to quantize the angular momentum. In the next two notes (reported at the meetings on September 24 and October 8, respectively), de Broglie came to the conclusion that the particle velocity is equal to the group velocity of phase waves, and the particle moves along the normal to surfaces of equal phase. In the general case, the trajectory of a particle can be determined using Fermat's principle (for waves) or the principle of least action (for particles), which indicates a connection between geometric optics and classical mechanics. [23]

This theory set the basis of wave mechanics. It was supported by Einstein, confirmed by the electron diffraction experiments of G P Thomson and Davisson and Germer, and generalized by the work of Schrödinger.

However, this generalization was statistical and was not approved of by de Broglie, who said "that the particle must be the seat of an internal periodic movement and that it must move in a wave in order to remain in phase with it was ignored by the actual physicists [who are] wrong to consider a wave propagation without localization of the particle, which was quite contrary to my original ideas."

From a philosophical viewpoint, this theory of matter-waves has contributed greatly to the ruin of the atomism of the past. Originally, de Broglie thought that real wave (i.e., having a direct physical interpretation) was associated with particles. In fact, the wave aspect of matter was formalized by a wavefunction defined by the Schrödinger equation, which is a pure mathematical entity having a probabilistic interpretation, without the support of real physical elements. This wavefunction gives an appearance of wave behavior to matter, without making real physical waves appear. However, until the end of his life de Broglie returned to a direct and real physical interpretation of matter-waves, following the work of David Bohm. The de Broglie–Bohm theory is today the only interpretation giving real status to matter-waves and representing the predictions of quantum theory.

Conjecture of an internal clock of the electron Edit

In his 1924 thesis, de Broglie conjectured that the electron has an internal clock that constitutes part of the mechanism by which a pilot wave guides a particle. [24] Subsequently, David Hestenes has proposed a link to the zitterbewegung that was suggested by Erwin Schrödinger. [25]

While attempts at verifying the internal clock hypothesis and measuring clock frequency are so far not conclusive, [26] recent experimental data is at least compatible with de Broglie's conjecture. [27]

Non-nullity and variability of mass Edit

According to de Broglie, the neutrino and the photon have rest masses that are non-zero, though very low. That a photon is not quite massless is imposed by the coherence of his theory. Incidentally, this rejection of the hypothesis of a massless photon enabled him to doubt the hypothesis of the expansion of the universe.

In addition, he believed that the true mass of particles is not constant, but variable, and that each particle can be represented as a thermodynamic machine equivalent to a cyclic integral of action.

Generalization of the principle of least action Edit

In the second part of his 1924 thesis, de Broglie used the equivalence of the mechanical principle of least action with Fermat's optical principle: "Fermat's principle applied to phase waves is identical to Maupertuis' principle applied to the moving body the possible dynamic trajectories of the moving body are identical to the possible rays of the wave." This equivalence had been pointed out by Hamilton a century earlier, and published by him around 1830, in an era where no experience gave proof of the fundamental principles of physics being involved in the description of atomic phenomena.

Up to his final work, he appeared to be the physicist who most sought that dimension of action which Max Planck, at the beginning of the 20th century, had shown to be the only universal unity (with his dimension of entropy).

Duality of the laws of nature Edit

Far from claiming to make "the contradiction disappear" which Max Born thought could be achieved with a statistical approach, de Broglie extended wave–particle duality to all particles (and to crystals which revealed the effects of diffraction) and extended the principle of duality to the laws of nature.

His last work made a single system of laws from the two large systems of thermodynamics and of mechanics:

When Boltzmann and his continuators developed their statistical interpretation of Thermodynamics, one could have considered Thermodynamics to be a complicated branch of Dynamics. But, with my actual ideas, it's Dynamics that appear to be a simplified branch of Thermodynamics. I think that, of all the ideas that I've introduced in quantum theory in these past years, it's that idea that is, by far, the most important and the most profound.

That idea seems to match the continuous–discontinuous duality, since its dynamics could be the limit of its thermodynamics when transitions to continuous limits are postulated. It is also close to that of Leibniz, who posited the necessity of "architectonic principles" to complete the system of mechanical laws.

However, according to him, there is less duality, in the sense of opposition, than synthesis (one is the limit of the other) and the effort of synthesis is constant according to him, like in his first formula, in which the first member pertains to mechanics and the second to optics:

Neutrino theory of light Edit

This theory, which dates from 1934, introduces the idea that the photon is equivalent to the fusion of two Dirac neutrinos.

It shows that the movement of the center of gravity of these two particles obeys the Maxwell equations—that implies that the neutrino and the photon both have rest masses that are non-zero, though very low.

Hidden thermodynamics Edit

De Broglie's final idea was the hidden thermodynamics of isolated particles. It is an attempt to bring together the three furthest principles of physics: the principles of Fermat, Maupertuis, and Carnot.

In this work, action becomes a sort of opposite to entropy, through an equation that relates the only two universal dimensions of the form:

As a consequence of its great impact, this theory brings back the uncertainty principle to distances around extrema of action, distances corresponding to reductions in entropy.


Later career and writings

After receiving his doctorate, de Broglie remained at the Sorbonne, becoming in 1928 professor of theoretical physics at the newly founded Henri Poincaré Institute, where he taught until his retirement in 1962. He also acted, after 1945, as an adviser to the French Atomic Energy Commissariat.

In addition to winning the Nobel Prize for Physics, de Broglie received, in 1952, the Kalinga Prize, awarded by the United Nations Economic and Social Council, in recognition of his writings on science for the general public. He was a foreign member of the British Royal Society, a member of the French Academy of Sciences, and, like several of his forebears, a member of the Académie Française.

De Broglie’s keen interest in the philosophical implications of modern physics found expression in addresses, articles, and books. The central question for him was whether the statistical considerations that are fundamental to atomic physics reflect an ignorance of underlying causes or whether they express all that there is to be known the latter would be the case if, as some believe, the act of measuring affects, and is inseparable from, what is measured. For about three decades after his work of 1923, de Broglie held the view that underlying causes could not be delineated in a final sense, but, with the passing of time, he returned to his earlier belief that the statistical theories hide “a completely determined and ascertainable reality behind variables which elude our experimental techniques.”


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