Hello! I met some annoying problems on quantum field operators in QFT.They are as follows: (1)The quantum field operator( scalar field operator, for example),is often noted as φ（r,t). Can it be interpreted as like this: φ（r,t) is the coordinate represetation of a more abstract,theoretical operator φ in Hilbert space? (2)Is there exist the represetation(such as momentum, coordinate.....) which is similar to that in quantum mechanics in QFT? Thanks for reply!!!