Model Definition and 1000 Threads

I am a computer science under graduate,I am more interested in scientific research, so I am preparing to enrol myself masters in quantum computing or simulation sciences. before i join i want to research what are the scope and job opportunities are available for simulation sciences(like...

Dear Community, I was trying to reproduce the 2D GrayScott model given either here: http://blogs.mathworks.com/graphics/2015/03/16/how-the-tiger-got-its-stripes/ or here: http://www.joakimlinde.se/java/ReactionDiffusion/index.php?size=0 The reason was to create a nice screen-saver (so I am...

Question on SIR Model and using Eulers method for approximating a solution. Given the 3 ODEs of the SIR model dS/dt = -\betaSI dI/dt= -\betaSI - \gammaI dR/dt = \gammaI Ive been asked to produce in excel Eulers method for axproximate solutions. Given some initial values for S(0) and I(0) as...

This website <link removed> by some Japanese guy talks about a new Bohr model that can accurately calculate energy of Helium and other noble gases, as well as bonds, in non-relativistic level. (I happened to come across this website when I was searching about spinor.) He also reviews why old...

Lets assume there is an observable represented by the operator, ##\hat{A}##. It follow (I think) that the observed values and allowed states obeys an equation of the following form\begin{equation}\hat{A}|\psi^i\rangle=\lambda_f|\psi_f\rangle\end{equation} where $$|\psi^i\rangle = initial \ \...

All particles get their mass from the higgs field. But how? According to the standard model what is "mass" and how do particles get it?

I try to understan this article: https://en.wikipedia.org/wiki/Reynolds_number What does "... such as between an aircraft model in a wind tunnel and the full size version." mean? Why cannot we use a full size version in a wind tunnel or why cannot model be full size? Thank you.

Homework Statement Show mathematically that a model with: Ω_M0 = 3 Ω_Λ0 = 0.01 Ω_R0 = 0 Ω_T0 = 3.01 is a model that re-collapses in the future. Be certain to indicate at what value of the scale factor 'a' the expansion reverses and becomes contraction. Homework Equations It's hinted pretty...

I am working om multilayer hybrid plasmonic waveguide (Si-SiO2-Ag_SiO2-Si). I have to see effect of roughness on propagation length and other parameters. So in reference to that I am having some doubts: 1) I use CST microwave studio for numerical simulation. I am not getting any direct option...

I have some cubic box with light bulbs controlled by a dimmer. The dimmer is calibrated in degrees (0-270). I need help in coming up with a function that would accurately predict what the temperature inside the box would be after say.. 5 or 10 minutes. Basically, I need to come up with a...

I know that for SU(2), weak interaction, in the standard model the right handed leptons are singlets, (and right handed neutrinos don't exist). For right handed quarks are they singlets or doublets in the standard model. So is it (u d)R or is it just u(R) and d(R)

Hello, I am The Maker. I am here because I want professional feedback on my work. I have been building things with K'NEX and popsicle sticks since I was little and as a future engineer, I wanted real engineers to evaluate my potential. Please be honest, I am trying to improve my engineering...

Hey all! Thanks for reading. I'm currently following along in some reading and had some trouble with re-writing a Hamiltonian in Bogluibov-de Gennes form using Nambu notation (Nambu spinors). Here is the low down: Say we have a Hamiltonian: \frac{1}{2} \sum_{i=1}^{N} c_{i}^{\dagger} D c_{i} +...

We see it frequently stated that in the subatomic/quantum world, there is no reason that the arrow of time points in only one direction, that either direction for particles is equally valid and workable. (If I am mis-stating this let me know.) But what is the model of the universe that is...

Hello, I try to add a voltage noise using an arbitrary voltage source set as V=white(1). Since I couldn't find any info about that parameter for the white() function I decided to do a .noise analysis to see how it responds to different values of that parameter. Except I can't get any kind of my...

Homework Statement Hello all, I have a question regarding the damping constant for a model of a vertically oscillating mass on a spring. I have read through one or two similar questions on this site but I think I can manage to be a little more specific about what I'm asking. I am in a physics...

I would like to consider the interaction terms in the Standard Model which allow the following decay process: The only interaction terms in the Standard Model which allow this decay process are contained in the charged current interactions: $$\mathcal{L}_{cc} =...

I wasn't sure where to post this, I hope this was the right section. I've been struggling quite a bit with implementing an autocorrelation code into my current project. The autocorrelation as it is now, is increasing exponentially from 1 at the start of my MC run, and hitting 2 halfway through...

Homework Statement I look at the distribution ##(Y_1,Y_2,...,Y_n)## where ##Y_i=μ+(1+φ x_i)+ε_i## where ##-1<φ<1## and ##-1<x_i<1## . x's are known numbers. ε's are independent and normally distributed with mean 0 and variance 1. I need to find the the maximum likelihood estimator for μ and...

I am currently studying C Hammond's "Basics of Crystallography and Diffraction" (third ed.). In the first chapter ,concerning hard sphere model, I have found the following statement: There are, in fact, no examples of elements with this structure because, as the model building shows,the atoms...

Just found this new book on amazon. Looks interesting. I purchased. https://www.amazon.com/dp/0691167591/?tag=pfamazon01-20 The TOC, Preface, and intro could be found here http://press.princeton.edu/titles/11050.html I wish they included a sample chapter as well (the book in not cheap), but I...

Homework Statement "Someone with no initial capital ##S_0=0## invests ##k \frac{dollar}{year}## at an annual rate of return ##r##. Assume that investments are made continuously and that the return is compounded continuously." Find the solution ##S## that solves the differential equation...

In the Standard Model, for any particle, I have only found properties related to electromagnetic and gravitational (in fact mass does not necessarily mean it is a property related to gravity, but to emergy)forces like charge and mass. Why there isn't anything about the other two interactions...

The impact of a bowling ball on the shape of a stretched gridded sheet is often used as a tool to help some of us to better visualize how the presence of a mass influences the curvature of spacetime? However, while this kind of diagram is helpful, I think that it is misleading because it...

Homework Statement If we multiply all the design dimensions of an object by a scaling factor (f), its volume and mass will be multiplied by f^3. a) By what factor will its moment of inertia be multiplied? b) IF a 1/48 scale model has rotational kinetic energy of 2.5 Joules, what will be the...

So as a learning project I am trying to solve a transformer with losses but I am stuck. 1 coil L1 with N1 turns is excited by a sinusoidal voltage V1 with a resistor R1 in series. Wound around a common core with a second coil L2 with N2 turns and a resistor R2 also in series...

I created interpolative curvefits to the graph of Earth's density as a function of radius, shown here: (Image from Wikipedia) Earth is assumed to be a sphere of radius 6371 kilometers. The independent variable r is the geocentric distance as a fraction of the Earth's radius; i.e. the range of...

Hi all! Can anyone confirm (or point me to literature) that the dispersion relation for the attractive Kronig-Penney potential is correctly given on Wikipedia (https://en.wikipedia.org/wiki/Particle_in_a_one-dimensional_lattice): $$cos(ka) = cos(\beta b)cos(\alpha (a-b))-\frac{\alpha ^2 +...

Consider a Hamiltonian of the form $$H=\frac{p_x^2}{2m}+\frac{p_y^2}{2M}+\frac{k(y)x^2}{2}$$ where ##k(y)## is some free function which I can choose at will. For ##k(y)=k=constant##, the Hamiltonian is a trivial combination of a free particle with position ##y## and a harmonic oscillator with...

Hello, I have a project (model reaction diffusion brusselator 2d) ∂u/∂t=A+u^2v-(B−1)u+D1((∂^2)u/∂(x^2)+(∂^2)u/∂(y^2)) ∂v/∂t=Bu−u^2v+D2((∂^2)v/∂(x^2)+(∂^2)v/∂(y^2)) initial conditions: u(x,y,0) = 0.5 + y, v(x,y,0) = 1 + 5x. boundary conditions: ∂u/∂n = 0, ∂v/∂t = 0 n-external normal to the...

https://www.sciencedaily.com/releases/2016/12/161215080856.htm Can anyone provide the origin of this article.

Homework Statement Hello all, I have to determine the maximum height of a model rocket. The rocket is launched at an 45 degree angle The finale velocity is 15,69 m/s (v) the extutevelocety is 14,23 m/s (c) The total mass is 180 gram (m) or m0) The emty mass is 52 grams (mf) The mass pr sek is...

https://en.wikipedia.org/wiki/Cyclic_model it brings to mind as well the many worlds theory the cyclic model is shown in a futuruma episode where the professor builds a only forward time machine(consistent with relativity) but he goes so far into the future that he ends in the past of the...

I have a model which is quadratic (e.g. ##y = k x^2##). I'm comparing it against a large set of data (galaxy cluster masses) which spans several Log10 decades (e.g. ##10^{11}## to ##10^{15}## solar masses). What is the right way to say how good the data fits the model? Obviously the errors in...

Hello! I am a university student working on a project regarding a piezoelectric patch transducer, and RLC modelling of said transducer. Edit: After reading the rule post i think i should clarify this is not coursework homework, this is a thesis project. The short version of my question is how...

Hi. A simple model explains resistance in metals with collisions of the electrons with the stationary atomic cores. So I assume more collisions result in a higher resistance? But for the dissipated power we have ##P=U^2/R## , which is large for small resistance. I have difficulties combining...

Can someone please explain to me what it means what they say a model is "first and second order dependence?"

Hi I am looking around for some way to model magnetic fields through a simple core with an air gap similar to this image : I was thinking Comsol... but Comsol is so hard to figure out, their documentation is terrible... I was looking at FEMM, but its only on windows. Does anyone know how to...

In my problem the linear modal is defined as the first term in the series expansion of \sin(x) so: \sin(x) = x - \frac{x^{3}}{3!}+\dots \sin(x) = x is the linear modal. So with this, I then have to write \frac{d^{2}x}{dt^{2}} = -\sin(x) as a system of x^{\prime} and y^{\prime}, so...

Hi, I wonder why we assume the matter wave of an electron is standing wave. Is there any reason why it has to be standing wave?Is it because standing wave is the right "wave equation solution" that satisfies integer multiple behaviour of bohr model?

In the past few months, there appear some observational results supporting the linear coasting models for the universe. http://www.nature.com/articles/srep35596 http://iopscience.iop.org/article/10.3847/0004-637X/828/1/35/meta This brings the coasting models again to the centre-stage of...

How are Hofstader's Butterfly and Landau Levels in 2-Dimesnions related to each other, if at all ?

I am the database administrator of my university, so I have to build up the database from scratch. I am just wondering if there exists already some predefined database model for academic management which focuses on entities such as students, grades, courses, teachers and faculty buildings.

AFAIK antimatter was produced equality in the big bang, and in the matter antimatter fight the matter won . Does antimatter react to gravity the same as matter, surly if it does then the antimatter will be annihilated due to matter antimatter mixing IF matter repels antimatter how did the...

In case of Ising model we are working with effective Hamiltonian. So let's look to spins which interact. In a case of feromagnet energy function is defined by ## H=-JS_1S_2 ## We have two possibilities. ##S_1## and ##S_2## has different values. And ##S_1## and ##S_2## has the same value. In...

Hi. There's this nice water circuit model for electric circuits where pressure corresponds to electric potential and the (mass or volume) flow rate to electric current. In the water model, we can vary the pipe diameter along the circuit. Since water is practically incompressible, the flow rate...

greetings, here I found a Simulink model on mathswork, I want to replace the battery with a fuel cell, so I'm stuck at the level of the energy management block. here is the link of the model: https://www.mathworks.com/matlabcentral/fileexchange/28441-hybrid-electric-vehicle-model-in-simulink...

An exciton is a bound electron-hole pair (in a semiconductor). For this problem, think of an exciton as a hydrogen-like atom, with a negatively charged electron and positively charged hole orbiting each other. The permittivity of free space (ε0) is replaced with permittivity of the...

The observation model will be ##z=H\theta+v##, where ##z## is column vector containing the results, ##H## is the observation matrix, ##\theta## is the parameter vector and ##v## is a vector containing random additive noise. b.) In this case ##z##=[1 1 0; 1 0 1; 0 1 1; 1 1 1]*[##m_1## ##m_2##...

Is wave a physical object or its just a model?