Measuring particle position and velocity

[Zinite]

In a discussion of Heisenberg's Uncertainty Principle I read that we must shine light on a particle to measure its position and velocity. How does this work exactly? Does the particle cast a shadow on a wall detector? Or is its position inferred some other way?

 

[Sojourner01]

It's a thought experiment. The idea is that you have to have some kind of electromagnetic interaction with the particle in order to transmit information on its whereabouts - the precise mechanism doesn't matter - and in fact it's a slightly ropey idea, because the common interpretation of Heisenberg is that it isn't possible to measure both to arbitrary accuracy even in principle - that is, information of that precise sort cannot coexist in the same 'timeline' for want of a better word.

 

[denian]

The Heisenberg's Uncertainty Principle states that it is impossible to simultaneously measure the exact position and velocity of a particle with certainty. This is due to the inherent uncertainty and unpredictability of quantum particles.

To measure the position and velocity of a particle, scientists use a method called the "light scattering" technique. This involves shining a beam of light onto the particle and observing how the light is scattered. The position of the particle can be inferred from the location of the scattered light on a detector, while the velocity can be determined from the change in position over time.

It is important to note that the act of shining light onto the particle can also affect its position and velocity, as the light itself can exert a force on the particle. This is known as the "observer effect" and is a key aspect of the uncertainty principle.

In terms of casting a shadow, it is not exactly accurate to say that the particle casts a shadow on a wall detector. Instead, the scattered light from the particle is what is detected and used to infer its position and velocity.

Overall, the measurement of particle position and velocity is a complex process that involves both the interaction of light and the inherent uncertainty of quantum particles. It is a fundamental aspect of quantum mechanics and our understanding of the microscopic world.