Dirac’s idea - CHERIC · 2010. 6. 17. · Dirac’s idea All negative energy states are already...

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Dirac’s ideaAll negative energy states are already filledBy the Pauli exclusion principle, no additional electrons can have negative energiesHole behaves like a particle with

positive energy (hole is a “lack of a negative energy electron”)positive charge (absence of a negative charge)

Anti-electron = positron (not proton)

Dirac sea

vast invisible “sea” of negative energy electrons

at least 2mc2

Pair creation Pair annihilation

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거울상 대칭 형태상호 작용력 차이 존재

Matter-antimatter

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Carl AndersonDiscovered in 1932 in cosmic rayNobel Prize in 1936

Proton hypothesis (Dirac) does not work2 particles must have identical massOppenheimer, Stückelberg, Feynman

they replace the E<0 particles with other (anti)particles of opposite charge

Discovery of positron

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Cosmic ray

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Every particle has an antiparticle1955: antiproton

Chamberlain-Segrè, Berkeley1956: antineutron

Cork et al., LBNL1965: antideuteron

Zichichi, CERN and Lederman, BNL

1995: antihydrogen atom CERN, by now millions produced

Some particles (e.g., the photon) are their own antiparticles !

반물질의 발견 역사

Anderson saw a track in acloud chamber left by“something positively charged,and with the same mass as anelectron”

lead plate

bubble chamber

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Antiproton 발견 (1955)

incoming antiproton

“annihilation star”(large energy release from antiproton destruction)

Reproduction of an antiproton annihilation star as seen in nuclear emulsion (source: O. Chamberlain, Nobel Lecture)

π

π

protons and α particles protons an

d α particles

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Antineutron 발견 (1956)

incoming antiproton

“annihilation star”(large energy release from antineutron destruction)

Antiproton charge-exchange reaction into neutron-antineutron pair in propane bubble chamber (source: E.G. Segrè, Nobel Lecture)

π

π

p + anti-p→ n + anti-n

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CERNCenter of European Organization for Nuclear Research

입자 가속기

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원자내 구조

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Electronme=0.92x10-30 kgqe=1.6x10-19 C=-qp

Protonmp=1.7x10-27 kgqp=qe=2x(2/3)-1x(1/3)

Neutronmn=1.7x10-27 kgqn=0=1x(2/3)-2x(1/3)

e, p, n의 전하량, 질량

e

p

n

ud

u

dd

u

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현재까지 발견된 원자의 구성 성분

Increasing Mass

전하

+2/3

-1/3

0

-1

u (up) c (charm) t (top)d (down) s (strange) b (bottom)e (electron) μ (muon) τ (tau)

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Family 별 질량 발견 역사

νe

e−

u

d

1e family 2e family

νμμ−

c

s

νττ−

t

b

3e family

(1 MeV ≈1.8∗10-30 kg)

m [MeV]

≈0

0.511

3

6

m [MeV]

≈0

106

1250

120

m [MeV]

≈0

1777

174300

4200

\© 1998

\© 1998

\© 1998

19951974

1976

1975

1956

1897

1963

19631963

1937

1961 2000

178000

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1st family일정 형상을 지닌 모든 입자가여기에 속함

2nd, 3rd family빅뱅이후에 발생Cosmic ray나입자가속기에서만 관찰 가능

Leptons & Quarks

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Force particles

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Fundamental forces

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아인슈타인의 첫번째 도전불확정성 원리 위배 사례

빛의 상자: 광자 하나의 에너지와 방출되는 시간을 정확히 결정할 수 있다!?

보어의 해석시간과 에너지는 불확정성 원리에 지배 받는다?!

Paradox 1: 빛의 상자

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아인슈타인의 두 번째 도전국지성에 관한 EPR 역설

Einstein-Podolsky-Rosen무한히 멀리 떨어져 있을 때, 한쪽 스핀의 방향이 결정되면다른쪽은 측정하지 않아도 자동으로 결정된다!

슈뢰딩거 고양이측정전까지는 상태를 알 수 없다

Paradox 2: 국지성