The determination of a particle's spin

  • Context: Undergrad 
  • Thread starter Thread starter Randall71284
  • Start date Start date
  • Tags Tags
    Determination Spin
Click For Summary

Discussion Overview

The discussion revolves around the determination of a particle's spin, particularly in the context of measuring spin in the presence or absence of electromagnetic fields. Participants explore the implications of measuring spin and the uncertainty associated with it, as well as methods used to measure spin without electromagnetic fields.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • One participant questions how to determine the presence of electric or magnetic fields if the spin of a particle cannot be distinguished without them.
  • Another participant challenges the idea of measuring spin without applying an electromagnetic field, seeking clarification on the measurement process.
  • A participant reiterates the uncertainty of a particle's spin, suggesting that if electromagnetic fields affect the measurement, it raises questions about the necessity of applying such fields.
  • It is noted that quantum mechanics states a particle's spin is indeterminate until measured along a specific axis, leading to discrete possible values.
  • A later reply asserts that many particle spins, particularly for neutral particles, can be measured without electromagnetic fields, citing the measurement of neutrino spin through conservation of angular momentum.

Areas of Agreement / Disagreement

Participants express differing views on the necessity of electromagnetic fields for measuring spin, with some asserting that it is essential while others argue that it is not always required. The discussion remains unresolved regarding the implications of these differing perspectives on uncertainty in spin measurement.

Contextual Notes

Participants highlight the complexity of measuring spin and the potential influence of electromagnetic fields, but do not reach a consensus on the conditions under which spin can be measured or the implications of such measurements.

Randall71284
Messages
2
Reaction score
0
If I am unable to distinguish the spin of a particle in an absence of an electric field or magnetic field, how am I able to determine whether there is an electric or magnetic field in a real-life context?

How is it that we can be sure of the uncertainty of the spin of particles if we are unable to create a situation in which there is an absence of an electric or magnetic field?

If a small enough field could be ignored (as there still are fields, however small in magnitude, acting on every particle in the universe), is there a level of magnitude in which the electromagnetic fields can be deemed insignificant that the particle’s spin is unaffected?
 
Physics news on Phys.org
I don't understand what you mean. How else do you want to measure the spin of your particle than with applying some electromagnetic field?
 
I mean that if we could only measure the spin of a particle by applying an electromagnetic field, and since there must be an effect on the particle by some electromagnetic field, then is there a point in saying that we must apply some electromagnetic field to measure it? Will there be any uncertainty in a particle's spin?
 
Randall71284 said:
I mean that if we could only measure the spin of a particle by applying an electromagnetic field, and since there must be an effect on the particle by some electromagnetic field, then is there a point in saying that we must apply some electromagnetic field to measure it? Will there be any uncertainty in a particle's spin?
I'm also not sure what you're asking. QM says that a particle's spin (relative to any given axis) is indeterminate unless you measure its spin about that axis. If you do, you get one of a set of possible discrete values. In the case of an electron, for example, you get ##\pm \dfrac \hbar 2##.

What are you asking in relation to that?
 
Reply
  • Like
Likes   Reactions: vanhees71
"How else do you want to measure the spin of your particle than with applying some electromagnetic field?"
Most particle spins are measured without an electrical electromagnetic field, especially neutral particles.
The neutrino spin was measured using conservation of angular momentum.
 

Similar threads

High School What exactly is spin? Does the standard model work without spin?
  • · Replies 27 ·
Replies
27
Views
3K
Undergrad Question about Stern-Gerlach experiment
  • · Replies 12 ·
Replies
12
Views
3K
Undergrad Particle field strength and sensitivity
  • · Replies 0 ·
Replies
0
Views
859
Undergrad Potential energy of spin anti-alignment
  • · Replies 14 ·
Replies
14
Views
4K
High School Is a Spin 2 Particle the Key to Understanding Gravitation in Quantum Mechanics?
  • · Replies 26 ·
Replies
26
Views
3K
Undergrad Why Does Spin Down Have Lower Energy Than Spin Up in a Magnetic Field?
  • · Replies 2 ·
Replies
2
Views
1K
High School Virtual photons as force carriers
  • · Replies 29 ·
Replies
29
Views
3K
Graduate Understanding spin precession in a magnetic field
  • · Replies 5 ·
Replies
5
Views
4K
Undergrad Conceptual question about spin state rotations
  • · Replies 5 ·
Replies
5
Views
2K
Undergrad Hamiltonian of a particle in a magnetic field
  • · Replies 10 ·
Replies
10
Views
4K