Unit vectors for multiple particles? (Quantum Mechanics)

In summary, the conversation discusses the notation and functional form of a wave function in multi-particle quantum mechanics. It is mentioned that the wave function consists of a tensor product of two spaces, with each particle having a unit vector representing its direction of movement. The question is raised about how to write the unit vectors when projecting the wave function onto the position basis. The correct answer is that the unit vectors do not need to be a tensor product, and the resulting amplitude is a complex number.
  • #1
Xyius
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It's been a little bit since I have studied multi-particle quantum mechanics and I am a little rusty on the notation.

Let's say I have a wave function, that consists of the tensor product of two spaces, one for each particle moving, ##|\psi_1,\psi_2>##. Each of these particles is moving in a certain direction defined by their respective unit vectors ##\hat{r}_n##, where ##n=1,2##.

If I were to project this wave function onto the position basis to obtain it's functional form, how would I write the unit vectors? Would the unit vectors also have to be a tensor product? For example,

[tex]<\vec{r}_1,\vec{r}_2|\psi_1,\psi_2>=f(\vec{r}_1,\vec{r}_2)\hat{r}_1 \otimes \hat{r}_2[/tex]

Would this be correct??
 
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  • #2
No, it's just an amplitude (complex number)
[tex]<\vec{r}_1,\vec{r}_2|\psi_1,\psi_2>=f(\vec{r}_1,\vec{r}_2) \in \mathbb{Z}[/tex]
 
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  • #3
MisterX said:
No, it's just an amplitude (complex number)
[tex]<\vec{r}_1,\vec{r}_2|\psi_1,\psi_2>=f(\vec{r}_1,\vec{r}_2) \in \mathbb{Z}[/tex]

Oh! Of course! Thanks!
 

1. What is a unit vector in quantum mechanics?

A unit vector in quantum mechanics refers to a vector with a magnitude of 1, which is used to represent the direction of a particle's motion in a multi-particle system. It is a fundamental concept in quantum mechanics that is used to describe the state of a system and its properties.

2. How are unit vectors used in multi-particle systems?

In multi-particle systems, unit vectors are used to represent the states of individual particles and their interactions with each other. They are also used to describe the position, momentum, and spin of each particle in the system.

3. What is the significance of unit vectors in quantum mechanics?

Unit vectors play a crucial role in quantum mechanics as they are used to represent the states of particles and their properties. They allow for the calculation of probabilities and expectation values of various physical quantities, which are essential in understanding and predicting the behavior of quantum systems.

4. How do unit vectors relate to the uncertainty principle in quantum mechanics?

The uncertainty principle in quantum mechanics states that it is impossible to know the exact position and momentum of a particle simultaneously. Unit vectors are used to represent the states of particles, and by calculating their expectation values, we can determine the uncertainty in these properties.

5. Can unit vectors be used to describe entangled particles in quantum mechanics?

Yes, unit vectors can be used to describe entangled particles in quantum mechanics. Entangled particles have a shared state, and unit vectors are used to represent this state and describe the correlations between the particles' properties.

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