What is the definition of a momentum *measurement*?

Click For Summary
SUMMARY

The discussion centers on the definition of momentum measurement in quantum systems, specifically how to infer momentum from measurements made with classical devices. The user seeks clarity on the connection between the momentum operator and actual measurements, emphasizing the need for specific conditions that a measuring apparatus must satisfy to qualify as a momentum measurement. The conversation highlights the lack of comprehensive resources addressing these conditions in quantum measurement theory.

PREREQUISITES
  • Understanding of quantum mechanics principles
  • Familiarity with momentum operators in quantum theory
  • Knowledge of measurement theory in quantum mechanics
  • Experience with classical measurement devices
NEXT STEPS
  • Research quantum measurement theory texts that discuss observable conditions for momentum measurement
  • Explore the concept of momentum eigenstates in quantum mechanics
  • Study the role of classical devices in quantum measurements
  • Investigate the relationship between quantum operators and measurement outcomes
USEFUL FOR

Quantum physicists, students of quantum mechanics, and researchers interested in the intricacies of quantum measurement theory.

pellman
Messages
683
Reaction score
6
Let's say I have made a measurement of some sort of a quantum system. That is, I have some macro/classical devices whose states have numbers associated with them, and their resulting states depend (in some way) on a quantum system. So I arrange the lab-plus-quantum system as desired and note down the numbers representing the states of the lab devices.

How do I then infer that I have measured the momentum of something?

I pose the question in terms of momentum rather than position because I suspect the position question may have a more straightforward answer. But I don't really know.

As far as the theory is concerned, I can speak of the momentum operator, and write the down what should be the state of the system (given the initial conditions to be arranged in the lab) in terms of momentum eigenstates, etc. But how do I connect this with a particular actual measurement?

I've read a few things over the years about quantum measurement theory but I have never seen a discussion of "Given an observable O, what conditions does the measuring apparatus have to satisfy for the result to be called a 'measurement of O'?"

Anyone know any texts which cover this?
 
Last edited:
Physics news on Phys.org
I don't have a complete answer, but you may find this thread interesting.
 
Thanks.

Fredrik said:
Some time ago, someone in this forum asked how you measure momentum. One of the answers said that if it's a charged particle, ...

I bet that someone was me. :biggrin:
 

Similar threads

  • · Replies 12 ·
Replies
12
Views
2K
  • · Replies 2 ·
Replies
2
Views
1K
  • · Replies 4 ·
Replies
4
Views
3K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 11 ·
Replies
11
Views
3K
  • · Replies 16 ·
Replies
16
Views
3K
  • · Replies 2 ·
Replies
2
Views
1K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 31 ·
2
Replies
31
Views
3K
  • · Replies 61 ·
3
Replies
61
Views
5K