In quantum mechanics, the classical variables are turned into operators, but these do not capture the state of the system, which is instead encoded into a wavefunction or more abstract ket vector. If is an eigenstate with respect to an operator , then for the corresponding eigenvalue , and hence letting an operator act on is analogous to multiplying by the value of the classical variable to which corresponds. By extension, a classical formula where all variables have been replaced by the corresponding operators will behave like an operator which, when it acts upon the state of the system, multiplies it by the analogue of the quantity that the classical formula would compute. The formula as such does however not contain any information about the state of the system; it would evaluate to the same operator regardless of what state the system is in.