In a related Phys.SE question about supersymmetric Lagrangian L=−12(∂S)2−12(∂P)2−12ˉψ∂/ψ, the fields S and P are said to be Grassmann-even supernumber-valued rather than real- (or complex) valued, so that supersymmetry transformations (with Grassmann-odd ε) δεS=ˉεψδεP=ˉεγ5ψδεψ=∂/(S+Pγ5)ε can be consistently defined.
My question is: can you still do path integral (or canonical) quantization of Grassmann-even fields (S and P) in the same fashion as real (or complex) scalar/pseudoscalar Boson fields? I am asking this because Grassmann-even supernumbers behave differently from real (complex) numbers. For example, the Grassmann-even ab (where a and b are Grassmann-odd) squares to zero (nilpotent) (ab)(ab)=−(aa)(bb)=0, which is totally different from a real (complex) number.
Answer
First of all, 1 complex (super)number can be viewed as 2 real (super)numbers, so it is enough to discuss real (super)numbers.
A field ϕ=ϕB⏟body+ϕS⏟soul that takes values in the set R1|0 of Grassmann-even real supernumbers can be quantized in the same way as a field ϕB that takes values in the set R of real numbers.
This is easiest to see in the path integral formalism, since an integral over a Grassmann-even real supernumber ϕ∈R1|0 is by definition given by the corresponding integral over its body ϕB∈R ∫R1|0dϕ f(ϕ) := ∫RdϕB f(ϕB).
The operator formalism can in principle be mapped to the path integral formalism.
See also this related Phys.SE post.
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