Preparation (physics)
Encyclopedia
Generally, measuring instrument
s are meant to get the (pre-)existent value of a physical quantity
of a system
with as little change of, or interaction with the system as possible. — If a measuring instrument fixes a physical quantity of a physical system for further use (post-existent), then the measurement process is called preparation.
For example, a graduated cylinder filled to a definite mark prepares a certain volume of the liquid for further use.
Though preparation measures a physical quantity — at least by fixing it — it often destroys previous states of the physical system. This is usually experienced in quantum mechanics
.
Measuring instrument
In the physical sciences, quality assurance, and engineering, measurement is the activity of obtaining and comparing physical quantities of real-world objects and events. Established standard objects and events are used as units, and the process of measurement gives a number relating the item...
s are meant to get the (pre-)existent value of a physical quantity
Physical quantity
A physical quantity is a physical property of a phenomenon, body, or substance, that can be quantified by measurement.-Definition of a physical quantity:Formally, the International Vocabulary of Metrology, 3rd edition defines quantity as:...
of a system
Physical system
In physics, the word system has a technical meaning, namely, it is the portion of the physical universe chosen for analysis. Everything outside the system is known as the environment, which in analysis is ignored except for its effects on the system. The cut between system and the world is a free...
with as little change of, or interaction with the system as possible. — If a measuring instrument fixes a physical quantity of a physical system for further use (post-existent), then the measurement process is called preparation.
For example, a graduated cylinder filled to a definite mark prepares a certain volume of the liquid for further use.
Though preparation measures a physical quantity — at least by fixing it — it often destroys previous states of the physical system. This is usually experienced in quantum mechanics
Quantum mechanics
Quantum mechanics, also known as quantum physics or quantum theory, is a branch of physics providing a mathematical description of much of the dual particle-like and wave-like behavior and interactions of energy and matter. It departs from classical mechanics primarily at the atomic and subatomic...
.