On the Genesis of Ladder Operators A. B. Sannigrahi Indian Institute of Technology, Kharagpur-721302, India The concept of operators plays a vital role in formulating the hasic principles of quantum mechanics. T o every dynamical variable in classical mechanics there corresponds an operator in quantum mechanics. These operators are usually assumed to be Hermitian in order to ensure that their expected values are real quantities. Let us consider a Hermitian operator, A, and a set of wellbehaved functions.. I1Li . . ...l. which belone to its domain. This implies that A$., is a qundrntirally inteirahle function, i.e., the interrill.. (Ad; . , .,Ad,, , .. is vositive-definite. Let us further a w m e tha
