Infinitesimal transformation of a field

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SUMMARY

The discussion centers on the infinitesimal transformation of a complex-valued field represented as Φ→eiαΦ. It is established that for an infinitesimal parameter α, where α² = 0, the transformation leads to the relation δΦ = iαΦ. This is derived from the approximation e^{iα} = 1 + iα, resulting in the expression Φ' = Φ + iαΦ, which confirms the stated relation for δΦ.

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marcom
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Hi,

Could you please explain me why, under the transformation of a complex valued field Φ→eΦ, for an infinitesimal transformation we have the following relation?

δΦ=iαΦ

Thanks a lot
 
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marcom said:
Hi,

Could you please explain me why, under the transformation of a complex valued field Φ→eΦ, for an infinitesimal transformation we have the following relation?

δΦ=iαΦ

Thanks a lot
When [itex]\alpha[/itex] is infinitesimal, i.e. [itex]\alpha^{2} = 0[/itex], you can write [itex]e^{i\alpha} = 1 + i\alpha[/itex]. So, [itex]\Phi \to \Phi^{'} = \Phi + i\alpha \Phi[/itex], leads to [itex]\delta\Phi = \Phi^{'} - \Phi = i\alpha \Phi[/itex].
 
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