I Ideas about observing position and momentum at the same time

[danielgossner]

TL;DR

Trying to think of new ways of viewing particles, without interacting with the electrons of that specific particle, as to view position and momentum at the same time with accuracy.

I am very interested in quantum mechanics/physics and i keep seeing the Heisenberg uncertainty principle and its making me think about other forms of viewing particles.

We traditionally use Photons to view something (our eyes), or other forms of radiation/particles, but i know that merely looking at an electron (casting light/radiation on it to view it) can change its position/momentum...but what if it didnt have to? What if you/something was able to observe the electron WITHOUT the use of a physical particle that acts on another particle. We use antimatter in medical technology and i know that when you combine matter and antimatter the electron is essentially destroyed or canceled out. What if we were to design a filter of some sort to capture or add equal force to an electron to prevent it from moving? i get that these things are super small and this is a relatively new form of science, but i lay awake at night with these thoughts.

 

[PeterDonis]

what if it didnt have to? What if you/something was able to observe the electron WITHOUT the use of a physical particle that acts on another particle.

This is not possible. Any kind of measurement or observation involves interaction with the thing being measured or observed.

when you combine matter and antimatter the electron is essentially destroyed or canceled out.

More precisely, an electron and its antiparticle, a positron, can annihilate each other and produce photons. But this is not a way to measure either the position or the momentum of either the electron or the positron.

What if we were to design a filter of some sort to capture or add equal force to an electron to prevent it from moving?

Electrons can be confined in magnetic traps that restrict their motion. However, that does not in any way evade or nullify the uncertainty principle.

 

[PeterDonis]

Moderator's note: Thread level changed to "I" and thread title edited to remove all caps.

(@danielgossner please be aware that all caps is the Internet equivalent of shouting.)

 

[PeroK]

i get that these things are super small and this is a relatively new form of science, but i lay awake at night with these thoughts.

Unfortunately your thoughts are based on a popular misconception of the HUP (Heisenberg Uncertainty Principle). The HUP is not about disturbing the electron when you measure it. The HUP is a statistical law and can be better phrased in terms of particle state preparation.

The HUP actually says that for an ensemble of identically prepared particles, there is a relationship between the standard deviations of momentum measurements and position measurements:
$$\sigma_x \sigma_p \ge \frac \hbar 2$$It says that you cannot prepare a particle in a state where there is a small variance in the results of position measurements and a small variance of momentum measurements. This applies even if you could measure the position of a particle without disturbing it.

As an example, if you confine an electron in a trap, hence there is a small variance in position measurements, then you will get a relatively large variance in momentum measurements.

If you wanted to disprove the HUP you would need a confined particle with a well-defined momentum. Whereas, what we find is the the more we confine an electron, the larger the variance in momentum measurements - which tends to support the HUP.

 

[Demystifier]

Actually, it is possible to measure simultaneously position and momentum, just not with a perfect precision. Typically, such a measurement prepares the system into a coherent state. For more details see https://www.sciencedirect.com/science/article/abs/pii/0003491692900862