Hi.. I want an explanation of the commutation relation. According to what I understand if two operators commute then they can be measured simultaneously. If they do not commute then the measurement of one depends on other as per the value of the commutator..I hope this is correct by far. In QFT, first of all, how can we use commutation relation for say a Klein Gordan Field? I mean how does it become an operator? Secondly, considering the equal time commutation relation between a scalar field and its conjugate field, which gives a commutator proportional to the dirac delta function. When the two are at the same point they are infinte...suggesting that the measurement of one destroys the possibility of measurement of the other. And If at two different point in space, the measurements can be made simultaneously. Is this correct? If so, what does this even imply? How does the measurement of one field affect the other..? I am not sure if I have been able to put my question properly, I hope I have. Thank you in advance.