Model Definition and 1000 Threads

'In the SU(3) quark model there are two singlet vector states $$|\omega_8 \rangle = \frac{1}{\sqrt{6}} \left(|u \bar u \rangle + |d \bar d \rangle - 2 |s \bar s \rangle \right) $$ belonging to the octet and the pure singlet state $$|\omega_1 \rangle = \frac{1}{\sqrt{3}} \left(|u \bar u \rangle +...

Hi guys, I have a question on the fundamental dynamic equation as I am not sure if my equation is correct. I am doing an analysis on a portal crane to find its application factor, somehow I couldn't get the desired value for the velocity of each masses as I couldn't find the tension of the...

I'm practicing for the Physics GRE, and came across a question that has me stumped. "In elementary nuclear physics, we learn about the Fermi gas model of the nucleus. The Fermi energy for normal nuclear density (ρ0) is 38.4 MeV. Suppose that the nucleus is compressed, for example in a heavy ion...

I am looking for 3D (or 4D, etc.) images of waves (such as light or sound), but seem to be having difficulty locating such models. Can someone please direct me to this kind of display, or is it not something being currently done?

Hi, I have a silly question, Could one, in theory make a accurate model of the life of our universe that one could look at from within. Let's say I put on my VR/AR goggles, 'there' Iam elevated from the earth, then I remain static, and the time begins to rewind. At some point I maybe hear...

I'm a bit confused about how things fill up in the shell model. Here is my understanding: the potential we are working with is the net potential due to the other nucleons that a proton or neutron feels throughout the nucleus; it is a combination of a square and harmonic oscillator potential...

Hello, I am trying to figure out the width of bands in a 1-dimensional lattice. Here is a short derivation from the book I am reading: if we approximate the free electrons as being in a square well then the energy levels are ## \frac{\pi^2 \hbar^2 n^2}{2mL^2}##. If there are ##N## ions...

Greetings, I am slightly curious as to whether the LCDM model may require a slight tweaking. The reason I am curious is because I recall reading a while back that removing the homogeneity assumption from our current models could assist in accounting for some of the large-scale structures, and...

Homework Statement In a double slit experiment, the distance between the slits is 0.2mm and the distance to the screen is 150cm. What is the phase difference in degrees, between the waves from the two slits arriving at point P, when the angular distance of P is 10 degrees relative to the...

Homework Statement Light of a wavelength 548nm illuminates two slits separated by 0.25mm. At what angle would one find the phase difference between the waves from two slits to be 2 rads? Homework Equations σ / λ = ΔΦ / 2π σ: path difference λ: wavelength Δφ: phase difference The Attempt at a...

Dear friends: Put a big disk in the space which can rotate at a speed. for example, if the radius of the disk is 10000km, and it rotates at a speed of 30 rad/s, then the speed at the disk boundary is 30,0000km/s. am i right?

Hi, I'm trying to implement an auto track guidance system for ground vehicles (Eg Tractors), I'm using Matlab and Simulink. I'm at a point where I can calculate heading errors. I'm not too sure how to calculate the lateral errors. Also, I need help in designing the controller. I'm using...

I understand that otical bistability only occurs in a specific parameter regime defined by the bimodial leaf, but I have read that bistability originates from highly non linear dynamics of the system. As we are dealing with a qubit in a cavity that is being driven so things become non-trivial...

From the reading I have done: In the presence of a drive, which is described by an addition term in the Jaynes-Cummings Hamiltonian, the Hamiltonian cannot be solved analytically. The dynamics of the system become non-trivial, with the behaviour depending on the specic parameter regime. So, the...

Homework Statement Program, without any built in functions (like ODE45), a solution to the Blasius Equation in Matlab that outputs boundary layer profiles for given x values, u values, etc. Homework Equations 2f''' + f''f = 0 fj = fj-1 + Δη/2 * (gj + gj-1) gj = [Δη2/4][2gj+1/Δη2 + 2gj-1/Δη2 +...

I've been trying to learn more about the standard model. Leonard Susskind's lectures have been very helpful for SR, GR and QM. His lectures about the standard model are interesting, I learned a lot, no question. But he doesn't really cover in any depth the mathematical side of it. He mentions...

Dear Sir, Assuming that my lottery machine can generate 10 numbers (0..9), in which 0 and 9 are supposed to be starting and ending states of my Markov chain. I apply Markov chain to model each number appearance because I would want to modify the random generation process into, say, my own...

Hi, Is there a list of basic interactions in the standard model? Does anyone know where I can find this list of basic interactions in the standard model?

Homework Statement I wasn't sure where the most appropriate place to post this question is. But anyway. Which of these, if any, can be used as evidence that the Earth revolves around the sun. 1. The phases of the moon 2. The seasons 3. analemma of the sun 4. solar and lunar eclipses 5. the...

I noticed this in the arxivs, i thought the LCDM model was irifutable but it seems some are trying to better it. arXiv:1602.02103 [pdf, ps, other] First evidence of running cosmic vacuum: challenging the concordance model Joan Sola, Adria Gomez-Valent, Javier de Cruz Perez Comments: LaTeX, 6...

domainwhale submitted a new PF Insights post High Temperature Low Temperature Duality for the Ising Model on an Infinite Regular Tree Continue reading the Original PF Insights Post.

So I'm trying to create a very simple mathematical model for a very idealized theoretical situation of traffic flow. In this situation I'm considering vehicles to be points (no length) each going the same speed with the same distance between them. The vehicle in front (vehicle 1) slows down and...

Homework Statement The state space model of a nonlinear system is x'_1(t) = 2x^2_2(t) - 50 x'_2(t) = -x_1(t) - 3x_2(t) + u(t) Where x_1(t) and x_2(t) are the states, and u(t) is the input. The output of the system is x_2(t). Find the state space model of this system linearized at the...

Help. I'm really struggling with the general idea here. The intricacies of the theory are hopelessly beyond my cognitive reach. I'm just trying to get a general handle on the big picture concept. I read a bit where Lee Smolin referred to this model as a leading theory that characterized space...

This is a kind of cooperative problem solving post. But don't be too terribly 'focused' because likely I have missed important issues. I had not seen a dynamic illustration like this before: maybe I am over impressed, weak-kneed, like seeing Kate Hudson the first time?? In Wikipedia at...

Could the orbit filling order of electrons be more classical and less quantum? I attached a jpeg and need someone to do a electrostatics analysis of the CAD model version of it. Does anyone have an electrostatics software package and have time to do a finite element analysis on a 3-D part to...

I was told in high school that Rutherford's atomic model was wrong because an electron which is in acceleration must release energy. That's how electromagnetic waves are made. and then I was told that Bohr gave his model and solved this problem. By making energy quantized. But what I really...

I was in deep thought about the mass of photons (assuming they only impart "mass" as they approach a given mass) and wondered how that might work to model gravity as a continual stream of "virtual" photons. Does this sound unique or did I simply think up a way to describe tensors?

Homework Statement A motorised model plane is attached to a light string anchored to a ceiling. The plane follows a circular path of radius 0∙35 m as shown in Figure 2. The plane has a mass of 0∙20 kg and moves with a constant angular velocity of 6∙0 rad s−1 . (a) Calculate the central force...

I am trying to model metal NPs capped with organic agents to simulate their phase transfer behavior from aqueous to organic. Not doing computational chemistry courses has had me to disadvantage. Would love some initiation or a jump start primer for the same. Looking forward for cues to get me...

1) For standard non-linear least squares, the standard approaches are to either a) to use the jacobian to linearize, and proceed with linear regression, or to b) linearize the raw data 2) When data needs to be "fit" to a complicated model (e.g. some non-linear differential equation) that...

Hi Everyone, As part of my computational project in topological insulators, I wish to calculate the Z2 invariant in my tight binding model of Kane-Mele Graphene. I have so far produced band structure and surface states consistent with literature, and have been looking at the theory of the Z2...

Hi. I've only just started reading on M-theory. I'm otherwise a lay person so I'm going to have some basic questions. Here's my first. Standard Model has 17 elementary particles right? But doesn't M-theory say there's 18? Or 36 if you include the symetrical ones. So am I missing one particle...

Are there any good models, software or codes that can predict the probabilities of nuclear reactions where an atom of a given type strikes another atom of another type with a given energy? Or is this information only obtainable experimentally? To further clarify, I am interested determining...

I have a historical question which I'm not finding any reference for. I recall how my former professor of history of science told us that the geocentric model was still taught for about a century in the accademia, long after Galileo's discovery of the phases of Venus and long after the...

As I understand it, the standard spacetime model is a 4-dimensional geometric object, and that my personal history is just a particular curve in the model. Reality as I experience it though is that I move through time, and thus I have the concept of the present in which "now" corresponds to the...

Homework Statement If the AD curve intersects the AS curve in the intermediate section of the AS curve, can you calculate the increase in real output in the AD/AS model resulting from the $100 million increase in government spending? If not, what additional information would you need? Homework...

I realize that Wiki is not the preferred reference source here, but I'll go ahead with this question anyway... In the latest iteration of the article on the Standard Model is the statement, "We see that the mass-generating interaction is achieved by constant flipping of particle chirality." Is...

to create a new model on physics what do i need to have?

back ground http://arxiv.org/abs/0912.0208 Asymptotic safety of gravity and the Higgs boson mass Mikhail Shaposhnikov, Christof Wetterich (Submitted on 1 Dec 2009 (v1), last revised 12 Jan 2010 (this version, v2)) There are indications that gravity is asymptotically safe. The Standard Model...

I am really, really stuck! I am trying to write java code to model the solar system, or at least currently just earth, the sun and mercury. I've made a big mistake somewhere, the planets are very unstable and either move in a line or spiral inwards! I just wanted to check that I'm doing things...

Hi all, I'm currently trying to investigate the edge current on a finite strip of Zigzag Haldane model (spinless, pi/2 phase) and I measure the current (in my code) by taking the expectation value of my current operator which is a function of wavevector k, for each eigenvector of the...

it's commonly stated that the standard model has no dark matter candidate. axions and/or sterile neutrions are well motivated extensions of the standard model. if experiments show they exist and are a part of dark matter, would this still be within the framework of the standard model, or is it...

Homework Statement The problem I have been set is to rework the Drude model using clearly defined scattering statistics. Homework Equations The Drude model as we have been given it is in terms of momentum \vec{p}(t+dt)=(1-\frac{dt}{\tau})(\vec{p}(t)-q\vec{E}(t)dt)+(\frac{dt}{\tau})(0) Where...

Hello, In the Kinetic-Molecular model for gas molecules in a container it is assumed that the square of the x-y-z velocity components is the same, how is it possible that we assume this?

Consider the case of a distributed computing system based on the processor-pool model that has ##P## processors in the pool. In this system, suppose a user start a computing job that involves compilation of a program consisting of ##F## source file ##(F < P)##. Assume that at this time the user...

I am doing a experiment with model rockets to see if a added compression nozzle on a model rocket would make the engine perform better. As you can see in this picture there is a small clay nozzle immediate to the propellant. This is the same place that you put the igniter. My experiment is...

Homework Statement A student experimenting with model rockets measures the speed of a vertically-launched rocket to be 18.0 m/s when it is 75.0 m above the ground on the way up. The rocket engine fires from when the rocket is at ground level to when it is 8.75 m above the ground. If the rocket...

Is any of the conjectures in: http://arxiv.org/pdf/hep-th/9610043v3.pdf have been proven/disproven? what has been left still open? I am thinking of reading this article sometime in the future, hope it's digestable (but first need to finish my studies of QFT and GR.)

Hey everyone, I just made an account because I have a problem concerning angular momentum and precession. In the picture below you see the vectors l1 and l2 that make up total orbital angular momentum L precess around L. I can get my head around why that is the case. The same for s1 and s2...