# Questions tagged [network]

DO NOT USE THIS TAG for net work.

39 questions
Filter by
Sorted by
Tagged with
70 views

### Static equilibrium of a small spring network [closed]

Three springs $AB$, $OB$ and $CB$ with equal spring constants are fixed at the nodes $A$, $O$ and $C$ respectively and attached to a common node $B$, as shown below. The springs are at rest in this ...
• 105
31 views

### Understanding and computing the Ising Hamiltonian for a directed graph

Suppose I have a directed graph where I assume there exist Ising spins on each node of the graph. The Ising Hamiltonian, in the absence of an external field is given by $\tag{} H = - \sum s_i s_j$ ...
• 582
21 views

### $N$-Port Network connectivity matrix versus reflection coefficient

For a $N$-port network, if there are $x$ number of internal ports and $y$ number of external ports, we define a connectivity matrix which relates all internal ports to each other. The symbol usually ...
• 57
1 vote
65 views

### Two Port Network

So I'm studying $S$ parameters for two port networks. I've seen some special cases like what happens if port 2 is short circuited or if port 2 is matched with port 1. I was wondering what happens if ...
• 57
1 vote
138 views

### Loops in Loop Quantum Gravity

Am I correct in understanding that in Loop Quantum Gravity, loops are somehow interconnected with each other or interact, or is there some form of quantum entanglement between them? And if so, can we ...
1 vote
36 views

### Differences between the complex networks and social networks

How could I state in simple terms the differences between the literature of Complex Networks (after Albert-barabasi and Watts-Strogatz - Physics Literature) and the literature of Social Networks (...
91 views

### How do you explain the unit of this formula?

I have trouble trying to interpret the following formula: $$G_{SCI} = \mu N^{span} G^3 \mathrm{arcsinh}\,(\rho \Delta f^2)$$ $$G_{SCI} = \frac{P_{SCI}}{B},$$ where $P_{SCI}$ is the self-channel ...
1 vote
80 views

### Is there a minimum principle which governs neuronal activity in brain function? [closed]

Reinforcement learning is a well established field which attempts to explain the behavior and decision-making of toddlers, among other agents. The core principle of this theory is based on dynamic ...
• 2,340
56 views

### Pipe network analysis but without knowing about loops?

Pipe network analysis methods like the Hardy-Cross method require two conditions to be met. 1) The inflow to a node must equal the outflow from that node. 2) The pressure change along a complete loop ...
66 views

### What is the advantage of neutral atom quantum network advantage?

I'm interested in quantum network system using neutral atom for my interest of atomic physics. But I'm curious about what the advantage of the neutral-atom-based quantum network instead of other ...
• 173
115 views

### Could a scientist use the internet to detect gravitational waves?

According to my understanding (I'm not a physicist just a fan), LIGO measures the changes in two path's lengths to detect gravitational waves by sending a particle down each path at the constant speed ...
1 vote
20 views

### Is it possible to implement the Invaded Cluster Algorithm on a network of Ising spins rather than a lattice?

My main concern is how to know if a cluster has percolated the network. For a periodic square lattice it is easy to determine if the cluster percolates by looking at the size of the cluster (as given ...
1 vote
298 views

### Calculate the scattering matrix of a 3-port lumped element network [closed]

I can get S11 and S12 by terminating port 2 and 3 with Z0 and Zr respectively. But when I try to calculate S13 it seems less straight forward. The following is the network, taken from Gao, J. The ...
• 11
125 views

### What are exactly "norms" in spin networks? Are there any non-quantum spin networks?

Roger Penrose proposed a series of networks from which, fundamentally, space-time would emerge, called spin networks (https://en.wikipedia.org/wiki/Spin_network) In this article, it is said: Given ...
1 vote
129 views

### Why does S11 seem to be independent of transmission media in this RF transmission experiment?

Hi friends I am starting to characterize a system in which we will plan to measure the response of a sample of liquid to radio waves. In order to do this I am exciting two antennas with the ports of ...
• 75
1 vote
44 views

### In loop quantum gravity what is considered the initial conditions?

In LQG, the Universe starts off not from a singularity but of finite size. And there may be the idea of a pre-big bang crunch. Assuming the Universe is symmetric in time about the 'big bang'. What ...
• 5,966
14 views

### What influences the variance of signal transmission speed?

I'm currently thinking about the various sources that influence time when it is synchronized with the NTP protocol. One of them is the physical layer (OSI-model). When sending a bit over a cable, ...
• 875
383 views

### How does particle physics use deep neural networks to find particles?

Does anyone use deep learning: RNN, CNN or any other architecture of deep neural networks to asses the standard model or to detect new or unseen particles? What's the status these days in this ...
• 3,114
80 views

### Entropy of natural networks [duplicate]

How does one define the entropy of a natural network (say for example, a river network, or a morphological skeletal network of a lake in the figure below) ? For example, the following report suggests ...
• 427
121 views

### Percolation theory: What is the critical amplitude for the "backbone" of a 2-D network?

Disclaimer: I am just learning about percolation theory for the first time, so I am not too familiar with some of the terminology. Suppose you have a 2-D square lattice with bonds connecting sites. ...
• 183
315 views

### How to compute entropy of networks? (Boltzmann microstates and Shannon entropy) [closed]

I also asked in SO here a few days ago, thought it may be also interesting for physics-related answers. I would like to model a network as a system. A particular topology (configuration of edges ...
• 143
40 views

### How do low voltage differential signals transmit bits

For example: There is Din+ connected to pin a1 and Din- to pin a2. Suppose I am sending "0101". How does it get sent? If there was only Din connected to Pin a1, which has a voltage supply to the bank ...
• 3
152 views

### What is the physical interpretation of inductors and capacitors equations in Frequency(s) domain?

s-domain modelling of capacitor and inductor equation: V(s)=LsI(s)−Li(0−) I(s)=CsV(s)−Cv(0−)
1 vote
106 views

### Scalar fields of graphs

I am trying to find literature on the propagation of scalar fields over random graphs. Think of a network of ideal resistors (with a given degree distribution), with a voltage source at a random node....
83 views

### Geometric frustration in power transmission networks

I read this article concerning the detection of Braess Paradox on power transmission networks: http://phys.org/news/2012-10-power-grid-blackouts-braess-paradox.html Here is a quote from the article: ...
• 113
532 views

### Resistance Distance in large electrical networks

I am not tremendously familiar with electrical circuits (I have some memories, but too long ago) and now I have come accross a problem where I need to compute the resistance distance in a graph. So, ...
1 vote
74 views

### What are the first couple terms of the Taylor series for the evolution of this network of capacitors and resistors?

note: This is a computational problem, and I only need approximate accuracy, so the overall goal is, for a given accuracy and $\Delta t$ to compute the state of the system at $t+\Delta t$ to within ...
• 121
1 vote
95 views

### How can the response at the terminal end of an infinite ladder network be solved?

In a recent post: How can the transfer function of an infinite ladder network be used to solve real world problems? I reference how one can solve the transfer function (impedance) of an infinite ...
• 11.2k
1 vote
1k views

### How can the transfer function of an infinite ladder network be used to solve real world problems?

In his lectures on Physics, Feynman illustrates a mathematical 'trick' in formulating the impedance of an infinite ladder, LC network. It basically counts on the assumption that adding one more 'rung' ...
• 11.2k
632 views

### How does the spinglass algorithm work when used for community detection in networks?

I am reading the article "Statistical Mechanics of Community Detection" by Jörg Reichardt and Stefarn Bornholdt, which describes how to use the spinglass model from physics to determine communities in ...
• 21
79 views

### Any fractal physical model that generates time series which demonstrate heavy-tailed (non-Gaussian) behavior in some form?

I know that fractal structures have power-laws in various forms "hidden" in them. I am looking for the most simple fractal model that I can find that generates time series with, say, Pareto-...
1k views

### Dialing emergency numbers with no network available. How? [closed]

When the network is not available on my phone, it says "emergency calls only". It means that even if I'm in the middle of the desert, with no towers in the vicinity, I can dial the emergency number. ...
• 219
829 views

### Building a Faraday cage for mobile networks that is transparent for optical wavelenghts

A friend of mine is working on an architectonic project, where she designs a Faraday cage type of open space built in parks or other public places. The initial thought is to build it from some sort of ...
104 views

### Examples of evolving networks in physics [closed]

I'm a master student working on networks analysis in general. A network is something that has nodes and there are links between the nodes. Nodes and links could have attributes. An evolving network is ...
• 157
4k views

### What is the difference between scale-free network and small-world network? [closed]

What is the difference between scale-free network and small-world network? I can't understand from the definitions around the web if they are both the same name for one thing. Do both follow a power-...
• 1,199
318 views

### Why isn't data lost when sent over large distances?

I was thinking about how information is sent, for example through the atmosphere. There are plenty of obstacles, as well diffraction, etc. Still, no information is lost. How is information sent to ...
• 1,332
153 views

### Book reviewing current state of research on complex networks [closed]

Can anybody recommend a book reviewing the current state of knowledge and active research on complex networks? Not primarily a textbook but a true review of the field - ideally with references to ...
577 views

### Does the spin glass corresponding to a restricted Boltzmann machine have a characteristic timescale?

From what I gather, a Boltzmann machine can be identified with a spin glass. Though I don't know the details yet (and would welcome any references within the last 5 years--not, e.g. MacKay, etc.), I ...
• 341