Technical Definition
Consider a full Von Neumann measurement by giving a quantum description to both the system and the measuring apparatus . Suppose the dynamics can be described by a Hamiltonian of the form
where Hself is the self-interaction of the system and Hint is the coupling between the system and the measuring apparatus. Generally, the Hint term is modeled as "turning on" for only a brief time and yielding the ideal (weak) Von Neumann measurement:
This measurement is a QND measurement if
Read more about this topic: Quantum Nondemolition Measurement
Famous quotes containing the words technical and/or definition:
“In middle life, the human back is spoiling for a technical knockout and will use the flimsiest excuse, even a sneeze, to fall apart.”
—E.B. (Elwyn Brooks)
“According to our social pyramid, all men who feel displaced racially, culturally, and/or because of economic hardships will turn on those whom they feel they can order and humiliate, usually women, children, and animals—just as they have been ordered and humiliated by those privileged few who are in power. However, this definition does not explain why there are privileged men who behave this way toward women.”
—Ana Castillo (b. 1953)