Re: [新聞]磁單極子受證實,Dirac踢Maxwell下台
: B=▽╳A
: g ^
: An=── tan(θ/2) ψ
: r
在θ=π的地方 這一個向量場會爆掉 所以有一條singularity
: -g ^
: As=── cot(θ/2) ψ
: r
在θ=0的地方 這一個向量場會爆掉 所以有一條singularity
但是除去這兩條線跟原點 我們會發現
g ^
▽╳An=▽╳[──tan(θ/2)ψ ]
r
1 ∂ tan(θ/2)sin(θ) ^ 1 ∂ r tan(θ/2) ^
=g [──── ─ (─────────) r +── ─ (────────)φ]
r sinθ ∂θ r r ∂r r
2
1 ∂ 2sin(θ/2) ^ 1 ∂ ^
=g [──── ─ (───────) r +── ─ tan(θ/2)φ]
r sinθ ∂θ r r ∂r
^^^^^^^^^^^^^^^^^^^^
=0
2sin(θ/2)cos(θ/2) ^ g ^
=g [───────────]r= ── r
r^2 sin(θ) 2
r
===================================
-g ^
▽╳As=▽╳[──cot(θ/2)ψ ]
r
1 ∂ -cot(θ/2)sin(θ) ^ 1 ∂ r -cot(θ/2) ^
=g [──── ─ (─────────) r +── ─ (────────)φ]
r sinθ ∂θ r r ∂r r
2
1 ∂ -2cos(θ/2) ^ 1 ∂ ^
=g [──── ─ (───────) r +── ─ (-cot(θ/2)φ]
r sinθ ∂θ r r ∂r
^^^^^^^^^^^^^^^^^^^^^
=0
2sin(θ/2)cos(θ/2) ^ g ^
=g [───────────]r= ── r
r^2 sin(θ) 2
r
這兩條A在發散的地方之外 都可以得到一樣的B值 而這一個B值
妳對包住原點的曲面做高絲雞分 能得一個4πg的值 這一個值就相當於電荷一樣
不一樣的地方在於 妳是磁荷 而過程中 我們避開了發散的地方
也就是所謂的Dirac string 使得特定A只能定義局部的地方 而在其他能cover到的地方
我們用一個規範變換將他們做連結
--
-1 μν ╴ μ
L=─ F F +Ψ(iγ (∂ +ieA )-m)Ψ
4 μν μ μ
--
※ 發信站: 批踢踢實業坊(ptt.cc)
◆ From: 220.132.98.155
推
11/18 14:31, , 1F
11/18 14:31, 1F
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11/18 14:32, , 2F
11/18 14:32, 2F
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11/18 14:34, , 3F
11/18 14:34, 3F
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11/18 14:37, , 4F
11/18 14:37, 4F
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11/18 14:37, , 5F
11/18 14:37, 5F
B
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11/18 14:38, , 6F
11/18 14:38, 6F
※ 編輯: xgcj 來自: 220.132.98.155 (11/18 14:40)
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11/18 14:40, , 7F
11/18 14:40, 7F
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11/18 14:41, , 8F
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11/18 14:51, , 12F
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11/18 14:58, , 16F
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11/18 15:14, , 18F
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11/18 15:15, , 19F
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11/18 15:23, , 28F
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11/18 15:23, , 29F
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11/18 15:24, , 30F
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11/18 15:25, , 31F
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11/18 15:26, , 33F
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11/18 15:28, , 35F
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11/18 15:28, , 37F
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11/18 15:29, , 38F
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11/18 15:29, , 39F
11/18 15:29, 39F
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11/18 15:30, , 40F
11/18 15:30, 40F
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11/18 22:10, , 41F
11/18 22:10, 41F
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11/19 07:41, , 42F
11/19 07:41, 42F
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11/19 09:04, , 43F
11/19 09:04, 43F
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11/19 10:56, , 44F
11/19 10:56, 44F
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11/19 10:56, , 45F
11/19 10:56, 45F
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