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I am reading chapter 5 of Ryder regarding path integrals and vacuum to vacuum transition amplitudes in presence of source.

I follow the math but don't have a clear physical picture.

The formula is:

[tex] Z[J]=\int Dq \: exp ( \frac{i}{h}\int dt(L+hJq+\frac{1}{2}i\epsilon q^2) )

[/tex]

Can someone explain what this is the transition amplitude of please?

Ithinkits saying:

1) pick a point in space

2) overlay a source (eg EM field)

3) A particlemaybe raised above the vacuum ground state at some point but ultimately at the beginning and end of time the vacuum will stay the vacuum - ie the vacuum will never turn into a stable particle.

I don't really think this is correct so please correct me!

:)

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# Vacuum to Vacuum Amplitudes and Functional Integrals

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