Questions tagged [randomness]
Randomness covers questions having to do with the concept of randomness in physical processes and questions about determinism vs indeterminism or interpretations thereof. Question related to concepts of probability may also use this tag.
240 questions
6 votes
6 answers
1k views
Does nature work exclusively on the cause-effect principle?
Does nature work exclusively on the principle of cause-effect or are there situations in which the principle is violated? Is randomness in probabilistic process truly fundamental or just a reflection ...
- 1,004
1 vote
1 answer
101 views
Where can I find information about Random Processes's Characteristic Functionals and Volterra series?
At first, hi everyone. I'm having difficulties looking for information about the so-called 'characteristic functional' of a random process. What I know about this concept is what follows: when you ...
2 votes
1 answer
159 views
Clarification about random field energy in Imry-Ma argument
Consider the Ising model in $d$ dimensions with a random local magnetic field $H_i$: $$ \mathcal{H} = -\frac{J}{2} \sum_{\langle i, j \rangle} S_i S_j - \sum_i H_i S_i $$ where $\langle i, j \rangle$ ...
- 77
2 votes
1 answer
149 views
How do 1-dimensional random walks correspond to different interpretations of stochastic integration?
Very short summary of my problem: I want to intuitively understand why/how random walks with "random barriers"/"random traps" correspond to the Itô/Hänggi-Klimontovich ...
- 586
0 votes
0 answers
57 views
Why randomness taking a specific outcome at that time? [duplicate]
Im a 16 year old and this question stuck in my mind. I cant find apt answer. Imagine we tossed a coin, we have 50-50% chance to get heads or tails. We say its random but truly we can predict the ...
- 21
2 votes
0 answers
66 views
Phase transition of shift of energy level under small perturbation in random matrix theory
I'm a mathematician and I'm thinking about a question in random matrix theory. Suppose $H_0$ is a $N\times N$ GUE random matrix (variance of each element is $\frac{1}{N}$). We consider a small ...
- 21
1 vote
6 answers
2k views
Where is an electron "physically" in superposition? [duplicate]
According to simple Google search: When an electron is in superposition, its different states can be thought of as separate outcomes, each with a particular probability of being observed. An electron ...
- 167
4 votes
2 answers
241 views
Has anyone constructed an explicit hidden-variable theory that reproduces the predictions of quantum mechanics for two separated qubits?
Consider the Hilbert space $$\mathcal{H} = \mathrm{span}\left( \{ |0\rangle\ |0\rangle, |0\rangle\ |1\rangle, |1\rangle\ |0\rangle, |1\rangle\ |1\rangle \} \right) \cong \mathbb{C}^4$$ of (pure) ...
- 52.3k
0 votes
0 answers
148 views
The source of random information in physics
In computer science, we can use the heat of a gas (or radiation, for example) to generate random noise. From them we can get a lot of random information. However, the question arises, where does this ...
- 129
7 votes
4 answers
767 views
What is the quantum mechanical root of causality?
Consider the following 3 premises. Premise 1) Quantum mechanics has an inherent randomness. Premise 2) Objects in the world appear to obey causality. For example, I can push a book on a table, and it ...
- 2,015
0 votes
1 answer
137 views
Microscopic level randomness [closed]
I have a fairly simple question but can't find any clear answer anywhere it seems. Let's say you would isolate an unstable nucleus and just wait for it to decay. You would know of the decay by having ...
1 vote
0 answers
56 views
System size scaling of sums of random lognormal variables
I will not go too much into details, but my question may be summarized as follows: Suppose you have a system of size $N$ and two lognormal-distributed random variables $A$ and $B$ associated with said ...
- 41
1 vote
5 answers
351 views
How can events on the quantum-level be random but not on the macro-level? [closed]
This question has been asked before on PSE, many times, and I have looked at them. But I don't think any of them get to the crux of my question. My chair is made up of quindecillions of atoms (not ...
0 votes
1 answer
136 views
Is power spectrum a sufficient condition for determining autocorrelation function via Wiener–Khinchin theorem?
For an optical source with power spectrum as 𝐼(𝜔), the autocorrelation function is related to power by a Fourier relation (Wiener–Khinchin theorem). F{𝑔(𝜏)} = 𝐼(𝜔) However, the above relation ...
1 vote
4 answers
253 views
Quantum: Which improbable macroscopic events are possible?
Basically, the title. Web search had not found pages in top results with similar QA. E.g. I understand nuclear blast can just end at any time because random chain-reaction has probability of not ...
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