# Tagged Questions

This tag is for Heisenberg's quantum mechanical uncertainty principle. DO NOT USE THIS TAG for uncertainty in a non-quantum measurement.

170 views

289 views

### Do black holes violate the uncertainty principle?

If black holes have mass but no size, does that imply zero uncertainty in position? If so, what does that imply for uncertainty in momentum?
203 views

### What state the wave function collapses into after an inaccurate measurement?

I'm watching MIT online lectures Quantum Physics I (roughly from one hour mark in the video). The lecturer explains wave functions that describe "Stationary States" that consist of a single energy ...
163 views

### Momentum uncertainty of free particle

I've read several Q&A's regarding free particles and the associated wave packet in this website, but found the answer to my question nowhere. It's OK to attribute a Gaussian wave packet to the ...
86 views

### Does the Heisenberg uncertainty principle preclude moving in a straight path with certainty?

The uncertainty principle is σₓσₚ ≥ 0.5 ℏ where x is position and p is momentum. Consider a 2d plane. If one moves along a straight line along the plane (possibly backtracking or moving forwards but ...
88 views

### Does the uncertainty principle affect event horizons? [duplicate]

I was thinking about black holes. For a simple black hole the event horizon is given by a distance of 2 times mass (energy) of the black hole. (2m). But according to quantum mechanics, if you try to ...
84 views

### Uncertainty principle

I am reading about uncertainity principle. My textbook says, if $λ$ is the wavelength of the radiation used to observe the particle then the position of the particle cannot be determined with ...
272 views

### Uncertainty principle in quantum field theory

Can the uncertainty principle be derived in quantum field theory? If yes, does is have a different interpretation than quantum mechanics because the coordinates $x_i$ are now parameters and not ...
712 views

### Heisenberg uncertainty principle clarification

I found these two examples in a books which demonstrate Heiseberg's uncertainty relation: 1) It shows that when we try to locate a moving electron,we transferred momentum via the photon that we ...
81 views

### Heisenberg uncertainty principle applied to large bodies?

Suppose I have a ball of a certain radius inside a box (with the length bigger than the radius) such that the ball fits in the box. The ball has a large mass (1 Kg). Heisenberg uncertainty principle ...
264 views

### Why does the uncertainty principle relate position and momentum when mass is always certain?

Why do physicists relate $x$ and $p$, instead of $x$ and $v$ since mass is well known and is not uncertain?
106 views

### Is entanglement a consequence of the uncertainty principle?

I am an aspiring physicist and once, I asked my professor on what triggers quantum entanglement and he graciously remarked "The great uncertainty principle!" - I was slightly confused and didn't say ...
It is known that $\Delta p \Delta x \geq \frac{h}{4\pi}$. I read that the two uncertainties must be along same axes. Why is that so?