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.
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Can 3 objects with same mass dropped from 10,000ft land in the same region/area together? [closed]
I mean specifically VERY close together, like in the same spot next to each other? And specifically, for example, objects such as 3 separate elastic band-bound bundles of €20 bills amounting to €2,000 ...
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Stochastic thermodynamical entropy production on growing state space
Suppose we have a stochastic process for a biased random walker starting at a position $x_0 = 0$. At a discrete time $n$, it can either move a distance $s^n$ to the right with probability $p$ or a ...
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How do I compute the bounds of random walk for a given ellapsed time?
I am trying to model random walk of a gyro, given some manufacturer specifications of maximum random walk in units of degrees per root-hour.
My first step was to generate white noise with a standard ...
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Which textbooks for random (Brownian) motion derivations? [duplicate]
I am a chemist currently trying to dive in to details of random motions. I have been studying Einstein-Smoluchowski treatment, and want to learn further (Fokker-Plank's equation and Langevin treatment ...
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Error analysis for counting experiments
i am trying to refresh my knowledge in error analysis and stumbled over an interesting question.
Suppose i have a radioactive compound and i want to measure the standard deviation of the decay count. ...
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Are linewidth of the laser source and vacuum fluctuations measured using the homodyne detection independent?
For Vacuum fluctuations based QRNG source, how will the linewidth of the laser source affects the shot noise. If we decrease the linewidth of the laser source, will we get a better output.
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Is randomness in quantum physics adequately formulated?
According to most experts' interpretations of quantum physics, some quantum event outcomes are random; they are not part of any cause-and-effect chain.
I'm struggling to find a thorough definition of ...
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Is Quantum randomness true randomness? [closed]
I would like you guys to read it, and see whether it makes sense, and correct me if anything is wrong.
I'm not an expert on these topics, so I understand if very wrong. It would be wonderful if you ...
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Is the universe deterministic, random, or both? [duplicate]
It occurred to me that the limits of possibility to the nature of the universe is it is either deterministic ie we are all at the will of natural laws that determine the outcome of events from the ...
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Is the random current model tight (in the sense of probability)?
Let us consider the random current model (of the classical Ising model) on $\mathbb{Z}^d$. More specifically, we have probability measures $\mathbb{P}_L$ on the product space $\mathbb{N}^{E_L}$ where $...
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Does the bias in a loaded die depend on gravity?
Suppose I bias a cubic plastic die by incorporating a lead pellet hidden just behind the '1' face, so that the probability $P_6$ of rolling a 6 is greater than the symmetric 1/6. Its exact behaviour ...
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Scientific determinism and the Heisenberg's uncertainty principle
I'm reading Brief Answers to the Big Questions by Stephen Hawking. In chapter 4, it discusses whether we can predict the future. As many have known that Laplace put forth that if we knew the positions ...
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Is Brownian motion truly random?
We say that Brownian motion is caused by the random collisions of particles. But let's consider an ionized gas; in that case, there's a nonzero net charge on the atom. Doesn't this mean the ...
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How accuratley can you determine the number of matchsticks in a matchbox from the sound it makes when you shake it?
This question is part of the International Physics Tournament 2023. The entire problem statement reads : How accurately can you determine the number of matchsticks in a matchbox from the sound it ...
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True Randomness/unpredictability in infinite quantum coin toss sequences?
In Comments on indeterminism and undecidability the abstract reads:
"In a recent paper 1, it has been claimed that the outcomes of a quantum coin toss which is idealized as an infinite binary ...
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Do random events really exist? [closed]
To highly clarify my question, let me define what I mean by a random event: "the event e is random, if and only if by having all the data about an event e, we cannot predict the consequences of ...
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Geiger tube counts-per-minute Poissonian, but counts-per-hour not. Why?
I am testing a Geiger tube and counting its pulses. Because the pulses are random, I expect the counts-per-minute (cpm) to follow a Poisson distribution. That's indeed what I found:
mean cpm = 38.39
...
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The Physical Meaning of Variance of Random Matrix Entries
I am trying to make some physical sense of the Hamiltonian described on pages 1, 2 here. The part I don't get is in the image attached below. I understand what the variance of each entry term tells me ...
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Sufficient and necessary conditions on random walk to obtain standard diffusion equation
In the simplest random walk model that is generally considered, the probability of the finding the particle at time $t$ in $x$, $P(x,t)$ is given by,
$$
P(x,t) = \frac{1}{2}\big[ P(x-a, t-\tau) + P(x+...
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Is the cosmic background radiation random and Kolmogorov complexity
In the article https://arxiv.org/pdf/physics/0510102.pdf the idea arises that if there was a Creator of the Universe and wanted to send us a message, then the "right" place to do it, would ...
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Per Newtonian mechanics, a coin toss exhibits deterministic chaos theory, but could relativity cause a probabilistic outcome of a coin toss?
It took me a long time to accept that a coin toss boils down to deterministic chaos theory. For example, the typical near 50/50 odds for outcomes of heads or tails results from complex initial ...
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How can randomness occur in the case of radioactive decay ? Isn't there supposed to be a rule for everything that's driven by a non conscious mind? [duplicate]
I'm not trying to be unscientific here but i cannot wrap this around my head that scientifically anything can work randomly except a conscious mind which is capable of making a random decision. how ...
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Does a random number generator have real entropy?
In thermodynamics, entropy is defined for gases. Of course, my laptop is not a gas. However, it contains a random number generator and I have seen the word ‘entropy’ being used in this context. Is ...
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Is there any paper/experiment on the deterministic behavior of coin-tossing?
I do not have background in Physics but Statistics. I am working on a small project on philosophy of probabilistic modeling.
Of course, we often model coin-tossing as if it comes from a Bernoulli ...
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Does the human brain use random number generators? [duplicate]
Neurons fire depending on the impulses they get from other neurons. This seems to be 'deterministic'. However, sometimes it might be useful to use random processes instead. Does the human brain have ...
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Conditional and unconditional interpretations of mean inter-collision times
This question appeared in a study guide for my graduate level written exam in physics. (It may have been the one from the University of Chicago.) I see that a similar question was asked here What is ...
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Kramers' Degeneracy and Geometric Symmetries
I am currently reading the third edition of 'Quantum Signatures of Chaos' by Fritz Haake and trying to work through section 2.7 (Titled "Kramers' Degeneracy and Geometric Symmetries"). I am ...
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Does quantum decoherence desctibe a deterministic universe?
QM describes a system, whose state evolve unitarily, which is deterministic. The apparent non-determinism comes from the measurement problem, where the state is projected to some subspace in a ...
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Is the randomness generated by quantum phenomena measurably better than the randomness generated by the best computational algorithms?
I am aware that quantum phenomena can be used to generate random sequences of numbers. Are such sequences measurably better than the random sequences generated by the best computational algorithms? ...
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Questions about the intuition on or physical meaning of probability space, random number, and stochastic process
I have a question about the physical meaning of, or the mathematical intuition on, the mathematical concept of probability space, random number, and stochastic process. Mainly, I would like to ask ...
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Information content needed to predict a physical coin flip perfectly [closed]
Let's just take a typical coin flip where a person flips the coin off their finger into the air (some reasonable distance, say 30-40 cm or so), catches it, and opens their hand to reveal one side face ...
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How to calculate variance of adjacency matrix $A$?
I'm studying random matrix theory.
How to calculate variance, $<A_{ij}^2>$ for every $i ≠ j$, if $A$ is a real symmetric $N × N$ uncorrelated random matrix? and I can't understand why the <A_{...
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Random matrix theory and the singularities of the Weingarten function
In the random matrix theory literature, one often encounters identities associated with averages over ensembles of random unitaries. For a simple example let's say we're interested exclusively in $2\...
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Cosmology context - MCMC code : Recomputation of covariance matrix after each point accepted
I am working on a MCMC code (basically with Metropolis-Hastings) and I would like to understand different important points.
We always mention the covariance matrix which is used in the computation of ...
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Is there consensus among physicists that reality is fundamentally deterministic? [duplicate]
Does Heisenberg’s Uncertainty Principle mean that the universe cannot deterministically be predicted by observers, or does it mean that the universe is inherently indeterministic, meaning that the ...
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What is the probability that a random walk forms (almost) a circle?
Given is a random walk of a particle in 3d (such as an atom in a liquid).
The particle proceeds randomly (in 3d), with an average straight displacement length a.
Is there a way to get a probability ...
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Why can’t quantum randomness be understood as epistemic? [duplicate]
I often hear people say that quantum randomness is “true randomness”, but I don’t really understand it. Please bear with my question.
Before the development of quantum physics, randomness is ...
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Is radioactive decay deterministic? [duplicate]
Suppose you know at time $t$ that there is some atomic nucleus that radioactively decays.
If you were to magically roll back the universe to the exact same state and let it continue as per usual ...
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Is there any concept in physics, that could potentially in the future get rid of "randomness"? [duplicate]
This question was very interesting to a non physicists like me question (I am computer scientist and I work with "pure random" crypto hardware that uses quantum phenomena) Obviously string ...
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Is a coin toss pseudo-random or truly random? [duplicate]
I wonder if a coin toss is pseudo-random or truly random. Sure, you could say that a coin toss is pseudo-random because you don't know the speed of the coin or its rotation, but if you were to include ...
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How many flips does a tossed macroscopic coin need to go through until the coinflip's result becomes indeterministic?
A coinflip is a macroscopic event and is deterministic in nature. A coin-flipping machine that operates at the greatest physical precision possible would be able to predict the coinflip's result (...
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Source of randomness
Is the random nature of all macroscopic phenomena like for example, turbulence or chemical kinetics ultimately traceable to quantum randomness?
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Annealed and quenched free energies
For the systems with random fields and interactions, annealed and quenched free energies are defined:
$$
F_a = -\theta\log\left(\overline{Z}\right),\quad F_q = -\theta\ \overline{\log(Z)}.
$$
Here, ...
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How are single photons correlated inside the "coherence time" of the laser? (And how would this affect a random number generator?)
This review on quantum random number generation describes how random numbers can be generated from a simple optical setup. In one example setup they give: weak light travels through a beam splitter ...
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Are phase transitions in one-dimensional random-field Ising model possible?
Translationally invariant one-dimensional models, with interactions of finite range and a finite number of states at the site, don't allow phase transitions at positive temperatures. This fact is a ...
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How to randomly generate a POVM for a qubit?
We all know that a POVM $\Pi$ is a set of operator such that
$$
\Pi = \left\{\Pi_k \quad s.t.\quad \Pi_k \geq 0 \quad \& \quad \sum_{k=1}^n \Pi_k = \mathbb{I}\right\}
$$
Let us assume that we are ...
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Interpreting distance in random walk
I've recently started reading about the random walk, from different sources across the internet, and there is this small detail that I'm not being able to wrap my head around.
Suppose we have, a ...
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Chaotic and Ordered Random Boolean Newtorks with a fixed in-degree k and a probability p
I'm working with Random Boolean Networks, I made a python program to show the dynamics of the networks. Before coding the program I study the theory and it says that the in-degree k and the ...
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Is there a relationship between quantum physics and chaos theory on a classical scale?
Im a complete physics lay person and I read somewhere that chaotic systems are subject to tiny differences in initial conditions and that the brain is a chaotic system.
Does that mean our thoughts are ...
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Is weather a phenomenon impacted by quantum randomness?
Im trying to find phenomena that impact our everyday lives that are subject to quantum randomness. And I was wondering whether weather might be one of them. Can an electron behaving slightly ...
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