What Is a C-Number in Quantum Field Theory?

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A c-number in quantum field theory typically refers to a classical number, distinguishing it from operators or spinors. The term is often associated with complex numbers but is primarily defined as a classical quantity. In discussions about spinors, which are anti-commuting, the reference to c-numbers indicates that spinors are composed of commuting numbers, not that the spinors themselves are commuting. Additionally, the term "anticommuting number" is more accurately associated with Grassmann numbers, which are used in the functional integral representation of fermionic fields. While some may refer to Grassmann numbers as c-numbers, this is not a common practice.
fliptomato
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Hello everyone--I was hoping someone could give (or refer to) a textbook definition of a c-number, as used in the context of quantum field theory.

Does this refer to a commuting number? I've also read it referring to a classical quantity. classical quantity, from a not-very-reputable source. (Though are these the same?)

If the 'c' refers to commuting, when I read something like "...spinors are anti-commuting (c-numbers)." (Bailin and Love, SUSY book) Does this mean that spinors are anti-commuting objects composed of commuting numbers? (It certainly doesn't mean that the spinors themselves are commuting...)

Thanks,
Flip
 
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C-number usually refers to "complex" number. At least that is all I have ever seen it used as.
 
c-number is really defined as a classical number. it is not an operator or
spinor.!

anticommuting number is Grassmann number used in the functional integral
representation of fermionic field.

Often the Grassman number is not called c-number, maybe someone can call
Grassmann number as c-number.
 
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