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5 votes

Is Heisenberg Uncertainty Principle (HUP) actually epistemic and not physical?

No, Heisenberg's uncertainty principle is actually a physical statement. But there are uncertainty principles which are even more fundamental than Heisenberg's: the uncertainty principle between time ...
Thomas Fritsch's user avatar
3 votes

Is Heisenberg Uncertainty Principle (HUP) actually epistemic and not physical?

No. The most classical example of HUP is the relationship between time and frequency/Energy. Consider a radar that wants to detect position and velocity of an object in the sky. If we produce a very ...
Paradoxy's user avatar
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2 votes

Is Heisenberg Uncertainty Principle (HUP) actually epistemic and not physical?

No. The Heisenberg uncertainty principle is an expression of the incompatibility of quantum operators, such as $\hat{x}$ and $\hat{p}$ of ordinary quantum mechanics or $\hat{\phi}$ and $\hat{\pi}$ of ...
Albertus Magnus's user avatar
1 vote

Interaction of light and charge leading to uncertainty in position?

When a single photon encounters a single electron, the energy level will be elevated. When the electron's energy level lowers it will emit new photons in random directions. To perceive this phenomenon,...
Bill Alsept's user avatar
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0 votes
Accepted

Aren't measurements in the Stern Gerlach experiment inherently intrusive to the states of particles?

I revisited this question recently. After thinking about it again, I realized that it is the formation of discrete lines on the output screen that points to quantization of spin. According to the ...
UVcatastrophe's user avatar
2 votes

Observation without interaction thought experiment

Heisenberg's uncertainty principle applies also to the photon field that $\vec E,\vec B$ come from, and implies that you cannot make an infinitely precise measurement of the electric field without ...
CR Drost's user avatar
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0 votes

Measuring Incompatible observables simultaneously of an entangled electron

Let $L$ and $R$ be the eigenstates of $x$-spin. Your system is in the state $L\otimes L+R\otimes R$ $=$ $U\otimes U+D\otimes D$, where $U=L+R$ and $D=L-R$ are the eigenstates of $y$-spin. (I am not ...
WillO's user avatar
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1 vote

In quantum mechanics, is there an actual difference between 'observation' and interaction?

A measurement is an interaction that records some information about the system being measured. The Elitzur Vaidman bomb tester (EVBT) fits into this way of thinking about measurement. In quantum ...
alanf's user avatar
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1 vote

In quantum mechanics, is there an actual difference between 'observation' and interaction?

There are differences depending upon the interpretation of QM. The main difference being whether consciousness plays a role. However,in relational QM pioneered Rovelli in the mid 90s, there is no ...
Mozibur Ullah's user avatar
7 votes
Accepted

How does the Planck constant enter into the uncertainty principle?

Notice that the kernel of the transform from position to momentum representations is $$ e^{- i x p / \hbar}. $$ Thus, comparing with your definition of Fourier transform, you need to have $$ \xi = ...
Aschkal's user avatar
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1 vote

Is measuring energy with arbitrary precision inherently impossible?

I assume that by a "strong measurement" you mean the standard "projective" measurement. In your second paragraph, the state that the measurement process needs to be time ...
just a phase's user avatar
1 vote

Is measuring energy with arbitrary precision inherently impossible?

Saying that a quantity can be measured with arbitrary precision means that you can measure it with any non-zero level of precision. So if you pick some particular non-zero number $\Delta E$ there is ...
alanf's user avatar
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0 votes

Is measuring energy with arbitrary precision inherently impossible?

It is impossible to measure anything with arbitrary precision and in particular energy. There are many reasons for that, one is your statement 1. but of course the concept of noise should be ...
yaron kedem's user avatar
-1 votes

Derivation of Bremermann's Limit

Bremermann's theorem is derived based on the time-energy uncertainty principle of Quantum Mechanics, and it imposes an upper limit on any physical activity in terms of speed of computation. ...
Adversing's user avatar
  • 161
0 votes

Uncertainties $\Delta r$ and $\Delta p_r$ for the hydrogenoid stationary states

Okay, I found what I was looking for : \begin{align} \Delta r \equiv \sqrt{\langle \, r^2 \rangle - \langle \, r \, \rangle^2} &= \frac{n a}{2 \mathrm{Z}} \sqrt{n^2 + 2 - \Bigl( \frac{l (l + 1)}{n}...
Cham's user avatar
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