Introduction to weak measurements and weak values

講演日:2019.04.17 (Wed)


Le, Binho(近畿大学理工学部)


In quantum mechanics, measurements of an observable of a quantum system allow for the prediction of the attentive characteristics of that system. The average value of the observable is described by its operator and the quantum wave function that represents the system state, and is well known as “expectation value.” If the system, however, described by a two-state vector, i.e., an initial state and a final state, such that the system’s initial state is preselected and its final state is postselected, then the corresponding average value is known as “weak value,” which was first named by Aharonov, Albert, and Vaidman in their groundbreaking study in 1988. Weak values mainly go along with weak measurements, which usually require an infinitely small interaction strength.
In this talk, I will introduce the basic concept of weak measurements and weak values. Together with this, I also will introduce some applications of weak values to interpret some quantum paradoxes including the EPR paradox, the Hardy paradox, the Cheshire cat paradox, and the violation of the pigeonhole principle.