This tag is for Heisenberg quantum mechanical uncertainty principle.
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Isn't the uncertainty principle just non-fundamental limitations in our current technology that could be removed in a more advanced civilization?
From what I understand, the uncertainty principle states that there is a fundamental natural limit to how accurately we can measure velocity and momentum at the same time. It's not a limit on ...
3
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11answers
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Could the Heisenberg Uncertainty Principle turn out to be false?
While investigating the EPR Paradox, it seems like only two options are given, when there could be a third that is not mentioned - Heisenberg's Uncertainty Principle being given up.
The setup is this ...
2
votes
2answers
503 views
Why don't quantum effects invalidate the speed of light barrier?
While proving that no matter can reach the speed of light (a fact which I call the kinetic energy barrier), Einstein uses the fact that he can calculate the velocity and position of an electron. ...
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2answers
366 views
Operators Uncertainty
$\hat A$ is an operator.
The uncertainty on $\hat{A}$, $\Delta A$ is defined by:
$$\Delta A=\sqrt{\langle\hat A^2\rangle - \langle\hat A\rangle^2}$$
what is difference between
$\langle\hat ...
12
votes
3answers
996 views
How does non-commutativity lead to uncertainty?
I read that the non-commutativity of the quantum operators leads to the uncertainty principle.
What I don't understand is how both things hang together. Is it that when you measure one thing first ...
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4answers
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Heisenberg Uncertainty Principle scientific proof
Heisenberg's uncertainty principle states that: if the x-component of the momentum of a particle is measured with an uncertainty
$$\Delta \vec p_x$$
then its x-position cannot, at same time, be ...
6
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6answers
803 views
Will Determinism be ever possible?
What are the main problems that we need to solve to prove Laplace's determinism correct and overcome the Uncertainty principle?
4
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5answers
299 views
What is $\Delta t$ in the time-energy uncertainty principle?
In non-relativistic QM, the $\Delta E$ in the time-energy uncertainty principle is the limiting standard deviation of the set of energy measurements of $n$ identically prepared systems as $n$ goes to ...
9
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2answers
206 views
Is the uncertainty principle just saying something about what an observer can know or is it a fundamental property of nature?
I ask this question because I have read two different quotes on the uncertainty principle that don't seem to match very well. There are similar questions around here but I would like an explanation ...
4
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6answers
314 views
Why is Heisenberg's uncertainty principle not an experimental error since it is the error created by photons striking on elementary particles?
Why is Heisenberg's uncertainty principle not an experimental error since it is the error created by photons striking on elementary particles?
2
votes
1answer
162 views
Will photon's energy be exactly same after million years?
If photon will travel for million years without collisions, what
subtle effects can be accumulated ?
Gravity fields affect trajectory, but is energy completely intact after fly by ?
Photon has its ...
10
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2answers
1k views
Meaning of the anti-commutator term in the uncertainty principle
What is the meaning, mathematical or physical, of the anti-commutator term?
$\langle ( \Delta A )^{2} \rangle \langle ( \Delta B )^{2} \rangle \geq \dfrac{1}{4} \vert \langle [ A,B ] \rangle \vert^{2} ...
4
votes
3answers
111 views
uncertainty of fields with many harmonic modes
In most basic level introduction to the quantum harmonic oscillator formulation of fields, it is assumed that the commuting variables for the fields $p_m$, $q_m$ are
$$ \lbrack p_m , q_n \rbrack = ...
7
votes
2answers
592 views
Why is the Heisenberg uncertainty principle stated the way it is?
I spent a long time being confused by the Heisenberg uncertainty principle in my quantum chemistry class.
It is frequently stated that the "position and momentum of a particle cannot be ...
2
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2answers
297 views
Naive question on quantum mechanics and uncertainty principle
This is a follow up on this question, the answer of which points towards Quantum Mechanics.
As stated I am not a phycisist so please forgive my ignorance.
I will try to understand the issue by going ...
18
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5answers
1k views
Does Heisenberg's uncertainty under time evolution always grow?
Recently there have been some interesting questions on standard QM and especially on uncertainty principle and I enjoyed reviewing these basic concepts. And I came to realize I have an interesting ...
11
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1answer
284 views
Quantum uncertainty of particle falling in black hole
A stationary observer at infinity sees a particle of mass m falling in a supermassive Schwarzschild black hole. He observes an increasing redshift and sees the particle ceasing to progress when it ...
12
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8answers
575 views
Why do quantum physical properties come in pairs?
Why do quantum physical properties come in pairs, governed by the
uncertainty principle (that is, position and momentum?)
Why not in groups of three, four, etc.?
-1
votes
6answers
309 views
What would be likely to completely stop a subatomic particle assuming it was possible?
Suppose that completely stopping a subatomic particle, such as an electron, could happen under certain conditions. What would be likely ways to get an electron to be perfectly still, or even just stop ...
8
votes
1answer
348 views
Do stationary states with higher energy necessarily have higher position-momentum uncertainty?
For simple potentials like square wells and harmonic oscillators, one can explicitly calculate the product $\Delta x \Delta p$ for stationary states. When you do this, it turns out that higher energy ...
7
votes
6answers
298 views
Does the HUP alone ensure the randomness in QT?
This answer of mine has been strongly criticized on the ground that it is no more than a philosophical blabbering. Well, it may well be. But people seem to be of the opinion that HUP alone does not ...
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3answers
521 views
Concept of a point particle in quantum mechanics
A point particle is usually thought of as structureless and without dimension. However, given that Heisenberg's uncertainty principle prohibits us from knowing the position of a particle exactly, what ...
4
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4answers
502 views
Uncertainty Principle for a Totally Localized Particle
If a particle is totally localized at $x=0$, its wave function $\Psi(x,t)$ should be a Dirac delta function $\delta(x)$. Accordingly, its Fourier transform $\Phi(p,t)$ would be a constant for all $p$, ...
4
votes
3answers
394 views
Very simple example of the way the Fourier transform is used in quantum mechanics?
According to a book I'm reading, the Fourier transform is widely used in quantum mechanics (QM). That came as a huge surprise to me. (Unfortunately, the book doesn't go on to give any simple examples ...
3
votes
1answer
336 views
Physical Significance of Fourier Transform and Uncertainty Relationships
What is the physical significance of a fourier transform?
I am interested in knowing exactly how it works when crossing over from momentum space to co ordinate space and also how we arrive at the ...
2
votes
1answer
159 views
Why shouldn't the uncertainty principle be interpreted as an observer effect?
The Heisenberg Uncertainty Principle suggests that the more precisely the position of a particle is measured, the less precisely its momentum can be known, and vice versa.
$$\sigma_x \sigma_p \geq ...
2
votes
1answer
267 views
3D Minimum uncertainty wavepackets
Based on the 1D case mentioned in Griffiths, I decided to try looking at the features of 3D Gaussian wavefunctions, i.e. (position basis) wavefunctions of the form $\psi(\mathbf{r}) = ...
2
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2answers
851 views
Noether's theorem vs. Heisenberg uncertainty principle
In continuation of another question about Noether's theorem I wonder whether there exists some kind of relationship between this theorem and the Heisenberg uncertainty principle.
Because both the ...
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vote
2answers
462 views
what is expectation values of this anti-commutator?
what is expectation values of this anti-commutator?
$$\langle \{ \Delta \hat x,\Delta \hat p\} \rangle$$
where the $\Delta \hat p=\hat p-\langle \hat p \rangle$ and $\hat p$ is momentum operator and ...
1
vote
3answers
551 views
Causality and Quantum uncertainty [duplicate]
Possible Duplicates:
Why quantum entanglement is considered to be active link between particles?
Why can't the outcome of a QM measurement be calculated a-priori?
Why do some (the majority ...
3
votes
2answers
316 views
Creation of particle anti-particle pairs
I was reading some QFT notes and there is one point that I don't understand, they are justifying why we need QFT saying that the number of particles is not preserved once we consider special ...
3
votes
4answers
820 views
What is meant by “Nothing” in Physics/Quantum Mechanics(QM)?
I am not a phycisist, so please forgive my ignorance. This is related to my posts and this.
I am trying to undertand what is meant by the term "Nothing" in physics or Quantum Mechanics since it seems ...
2
votes
3answers
493 views
Observation of violation of the uncertainty principle?
I stumbled upon this piece of news in the BBC's website http://www.bbc.co.uk/news/science-environment-19489385, discussing this paper
http://prl.aps.org/abstract/PRL/v109/i10/e100404, which reports ...
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1answer
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Exploiting the Heisenberg Uncertainty Principle as a means to communicate
It seems as though I've come across a rather unusual conclusion that could either simply be a misinterpretation or a contradictory discovery. I seem to have found a way to utilize the Heisenberg ...
