Prerequisites for studying Peskin and Schroeder

[Neitrino]

Gents,

Would you be so kind to help me with my question please which has been relocated
https://www.physicsforums.com/showthread.php?t=87659

Thanks in advance

 

[Neitrino]

Sorry but,

Could at least tell me why my question is not getting any replies?
Im very wondered... its too nonsensical ? If so what do I say wrong?

 

[snooper007]

I think the expresion $$<0|\phi(x)\phi(y)|0>$$
survives $$<0|a_p a_q^\dag|0>$$ means:
$$<0|a_p^\dag a_q^\dag|0>$$=0 and $$<0|a_p a_q|0>$$=0;
only $$<0|a_p a_q^\dag|0>$$ survives, of course p and q are arbitary,
not single p and single q. the final result will be an integral over all possible p or q.

(2) $$<0|\phi(x)|$$, is just complex conjugate of (2.41).
there is no special physical significance here, the author, I guess, just mentioned NR
case to make the formula be easily understood.

 

[Neitrino]

$$<0|\phi(x)=<x|$$ this is a simple calculation

(as u posted in homework section)

Dear Snooper007 thks for ur reply..
$$<0|\phi(x)$$ it is a complex conjugation of $$\phi(x)|0>$$
So $$<0|\phi(x)=\int{\frac{d^3 p}{(2\pi)^3}\frac{1}{2E_p}e^{ipx}<p|$$

$$<0|\phi(x)=<x|$$ < - ?

and with regard to question 1) I still don't feel comfort with understanding..
seems I did no understand ur reply as it should be

 

[vanesch]

I wonder in what colleges one studies Peskin and Schroeder...