Spin State Rotation: Understanding Negative Probability?

In summary, spin state rotation is a fundamental concept in quantum mechanics that involves changes in the orientation of a particle's spin when interacting with an external magnetic field. Negative probability is a mathematical concept used to describe the behavior of spin states, which does not mean that the probability is actually negative. This concept is important in quantum computing, where it is used to manipulate the states of qubits. Spin state rotation has been observed in experiments and is also used in technologies such as MRI machines. Understanding negative probability in spin state rotation is crucial in understanding the strange and counterintuitive behavior of particles at the quantum level, challenging our traditional understanding of probability and the nature of reality.
  • #1
eoghan
207
7
Hi there!
If I have an electron in the spin state |+> and I rotate it by an angle of 360°, then the state becomes -|+>. Now, if I want to find the probability of measuring the spin up, I have:
P(|+>)=<+|(-|+>)=-1
So after a rotation of 360° I have a negative probability??
 
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  • #2
Ok.. I found the error! I have to consider the square of -1 which is 1... really a stupid error :blushing:
 

1. What is spin state rotation?

Spin state rotation is a concept in quantum mechanics that describes the change in the orientation of a particle's spin when it interacts with an external magnetic field.

2. What is negative probability in spin state rotation?

Negative probability is a mathematical concept used in quantum mechanics to describe the behavior of spin states. It does not mean that the probability is actually negative, but rather that the mathematical equations used to describe the spin states may yield negative values.

3. How does spin state rotation relate to quantum computing?

Spin state rotation is a fundamental concept in quantum computing, as it is used to manipulate the states of qubits (quantum bits) which are the building blocks of quantum computers.

4. Can spin state rotation be observed in the real world?

Yes, spin state rotation has been observed in experiments using particles such as electrons and protons. It is also used in various technologies, such as magnetic resonance imaging (MRI) machines.

5. How does understanding negative probability in spin state rotation impact our understanding of the quantum world?

Understanding negative probability in spin state rotation is crucial in understanding the strange and counterintuitive behavior of particles at the quantum level. It challenges our traditional understanding of probability and forces us to think in new ways about the nature of reality.

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