Wavefunction of a single photon

Photon dynamics in the double-slit experiment, 3

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What equation describes the wavefunction of a single photon?

The Schrödinger equation describes the quantum mechanics of a single massive non-relativistic particle. The Dirac equation governs a single massive relativistic spin-½ particle. The photon is a massless, relativistic spin-1 particle.

What is the equivalent equation giving the quantum mechanics of a single photon?

— edited Jun 3 ’13 at 19:42

— Ben Crowell

— asked Nov 9 ’10 at 20:38

— nibot

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There is no quantum mechanics of a photon, only a quantum field theory of electromagnetic radiation. The reason is that photons are never non-relativistic and they can be freely emitted and absorbed, hence no photon number conservation.

— answered Nov 10 ’10 at 20:00

— Igor Ivanov

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You can also say that the wavefunction of a photon is defined as long as the photon is not emitted or absorbed. The wavefunction of a single photons is used in single-photon interferometry, for example. In a sense, it is not much different from the electron, where the wave-function start to be problematic when electrons start to be created or annihilated…

– Frédéric Grosshans Nov 17 ’10 at 10:19

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— Physics StackExchange

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2018.12.14 Friday ACHK

The fallacy of average

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Those in the print media who dismiss the writing online because of its low average quality are missing an important point: no one reads the average blog. In the old world of channels, it meant something to talk about average quality, because that’s what you were getting whether you liked it or not. But now you can read any writer you want. So the average quality of writing online isn’t what the print media are competing against. They’re competing against the best writing online. And, like Microsoft, they’re losing.

— What Business Can Learn from Open Source

— Paul Graham

— Me@2011.08.23

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2018.12.14 Friday ACHK

PhD, 2.2

故事連線 1.1.4 | 碩士 3.2

這段改編自 2010 年 4 月 18 日的對話。

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有很多人的「個人形象」和「公眾形象」,都是差天共地的。

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(問:即是表裡不一?)

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有時,甚至是「表裡相反」。

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(問:那應該怎麼辦?

除了在本科生年代,修讀心目中候選導師的課以外,還可以有什麼「測試」?)

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可以試試找他,做你的本科畢業論文的導師。但是,這個風險仍然太大。我不太建議。

風險較小的方法有,詢問一下,他現時的研究生。他們最知道,該教授的真正面目,究竟是真材實學,還是欺世盜名。

還有,即使他真材實學,也不代表他肯花時間,用心教導研究生。他會不會那樣做,只有他以前或現時的研究生,才會知道。

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(問:你好似講到,人類那麼危險?)

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因為事實上,人類的確是,那麼危險。

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剛才所講,有關選擇碩士或博士論文導師,所需的技巧,背後的精神,其實是通用的—同時適用於你將來選擇公司、上司、生意合作伙伴、配偶,等等。

選擇錯誤,同樣是有改變一生的後果。

— Me@2018-12-13 10:33:47 PM

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2018.12.14 Friday (c) All rights reserved by ACHK