Time Reversal Spin: Why Does it Require Flipping?

In summary, the question being discussed is why time reversal requires spin to be flipped. One participant suggests that orbital angular momentum reverses sign under time reversal because momentum reverses sign. They also mention that spin is angular momentum in the rest frame and must change sign under time reversal. However, they do not have a proof for this.
  • #1
aaaa202
1,169
2
Does anyone know why time reversal requires spin to be flipped? It seems like my book assumes that, but I have no idea why.
 
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  • #2
aaaa202 said:
Does anyone know why time reversal requires spin to be flipped? It seems like my book assumes that, but I have no idea why.

Well, it's obvious that orbital angular momentum reverses sign under time reversal, because it's [itex]\vec{L} = \vec{r} \times \vec{p}[/itex], and momentum reverses sign. Since angular momentum can move from spin to orbital, I don't think it would be consistent to reverse one and not the other. But I don't know of a proof.
 
  • #3
Spin is angular momentum in the rest frame. Angular momentum has to change sign under time reversal by definition.
 

Related to Time Reversal Spin: Why Does it Require Flipping?

1. What is time reversal spin?

Time reversal spin is a concept in quantum mechanics that describes the reversal of the spin direction of a particle, which is a fundamental property of particles.

2. Why does time reversal spin require flipping?

Time reversal spin requires flipping because it is a fundamental property of particles and cannot be altered without changing the nature of the particle itself.

3. How does time reversal spin affect particles?

Time reversal spin affects particles by reversing the direction of their spin, which can have implications for the behavior and interactions of particles on a subatomic level.

4. Is time reversal spin possible in everyday life?

No, time reversal spin is not possible in everyday life as it is a concept that is only applicable on a subatomic level and cannot be observed or manipulated in our macroscopic world.

5. What are some potential applications of time reversal spin?

Some potential applications of time reversal spin include quantum computing, magnetic storage, and understanding the behavior of subatomic particles in high-energy physics experiments.

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