Back Erwartungswert#Quantenmechanischer Erwartungswert German Valor esperado (mecánica cuántica) Spanish Valeur moyenne (quantique) French ערך תצפית (תורת הקוונטים) HE Ожидаемая величина измерения (квантовая механика) Russian Очікувана величина вимірювання (квантова механіка) Ukrainian 期望值 (量子力學) Chinese
In quantum mechanics, the expectation value is the probabilistic expected value of the result (measurement) of an experiment. It can be thought of as an average of all the possible outcomes of a measurement as weighted by their likelihood, and as such it is not the most probable value of a measurement; indeed the expectation value may have zero probability of occurring (e.g. measurements which can only yield integer values may have a non-integer mean). It is a fundamental concept in all areas of quantum physics.