The Naked Scientists
Toggle navigation
Login
Register
Podcasts
The Naked Scientists
eLife
Naked Genetics
Naked Astronomy
In short
Naked Neuroscience
Ask! The Naked Scientists
Question of the Week
Archive
Video
SUBSCRIBE to our Podcasts
Articles
Science News
Features
Interviews
Answers to Science Questions
Get Naked
Donate
Do an Experiment
Science Forum
Ask a Question
About
Meet the team
Our Sponsors
Site Map
Contact us
User menu
Login
Register
Search
Home
Help
Search
Tags
Recent Topics
Login
Register
Naked Science Forum
Non Life Sciences
Physics, Astronomy & Cosmology
How to choose random walk, diffusion? (local vs global entropy maximization)
« previous
next »
Print
Pages: [
1
]
Go Down
How to choose random walk, diffusion? (local vs global entropy maximization)
0 Replies
7787 Views
0 Tags
0 Members and 1 Guest are viewing this topic.
Jarek Duda
(OP)
Sr. Member
169
Activity:
0%
Thanked: 1 times
How to choose random walk, diffusion? (local vs global entropy maximization)
«
on:
03/09/2020 06:35:57 »
To choose random walk on a graph, it seems natural to to assume that the walker jumps using each possible edge with the same probability (1/degree) - such
GRW (generic random walk) maximizes entropy locally (for each step)
.
Discretizing continuous space and taking infinitesimal limit we get various used diffusion models.
However, looking at
mean entropy production
: averaged over stationary probability distribution of nodes, its maximization leads to usually a bit different
MERW
:
https://en.wikipedia.org/wiki/Maximal_entropy_random_walk
It brings a crucial question
which philosophy should we choose
for various applications - I would like to discuss.
GRW
- uses approximation of (Jaynes)
https://en.wikipedia.org/wiki/Principle_of_maximum_entropy
- has no localization property (nearly uniform stationary probability distribution),
- has characteristic length of one step - this way e.g. depends on chosen discretization of a continuous system.
MERW
- is the one maximizing mean entropy, "most random among random walks",
- has strong localization property - stationary probability distribution exactly as quantum ground state,
- is limit of characteristic step to infinity - is discretization independent.
Simulator of both for electron conductance:
https://demonstrations.wolfram.com/ElectronConductanceModelsUsingMaximalEntropyRandomWalks/
Diagram with example of evolution and stationary denstity, also some formulas (MERW uses dominant eigenvalue):
«
Last Edit: 03/09/2020 06:50:41 by
Jarek Duda
»
Logged
Print
Pages: [
1
]
Go Up
« previous
next »
Tags:
There was an error while thanking
Thanking...