Model Definition and 1000 Threads

Homework Statement The mean field solution for the Ising model is: $$m = tanh[\beta (mJz + H)]$$ I wanted to carry out a dimensional analysis in order to verify the equation. Homework Equations $$m = tanh[\beta (mJz + H)]$$ The Attempt at a Solution Knowing that: $$[m] = \frac{A}{L}$$...

Hello there, I'd like to model a simplified version of a "Magic Eye" tube (e.g. without the amplification triode, and for a start, 2 dimensions only), or the visible display behavior. What I'm talking about: https://en.wikipedia.org/wiki/Magic_eye_tube#Operation Here is a nicer depiction of...

I am trying to anallytically determine natural frequencies ƒ of the tympanic membrane. I am using 2D sectorial annulus membrane as a simplified model of tympanic membrane according to following picture The parameters that i want to use are following: THICKNESS = 0,1 mm The natural...

A coil is modeled as Z = jwL or Z = sL or V = L dI/dt What are the equations for an induction motor? Single-phase one.

They are described here as (2+1)-dimensional sheets of eta-prime condensate, with the valence quarks on the boundary. One amazing detail is that, because it is a lower-dimensional object, the quarks are anyons! This description is said to apply most immediately to single-flavor baryons like ∆++...

I have a cylinder of some dimensions. I have a compressible liquid inside. Assuming a constant temperature, no atmosphere, no convection currents within, because it is in a cylinder, there will be no variations in density horizontally (the fluid will have time to settle). Now because there is...

I'm currently doing a course on the Standard Model and I think I've gotten confused on some of the symmetries and resulting currents. Here's my current understanding: Before SSB: Electroweak - U(1) symmetry on fermion spinors and Higgs complex doublet, 1 conserved current Electroweak - SU(2)...

Hi Everyone, One of Hawking's last publications studied the model of universe/multiverse and conjectured that the exit from eternal inflation is "finite and reasonably smooth" - in other words, the inflated boundaries of multiverses could be finite and smooth. Here is the paper link -...

Hi all, I am having trouble understanding the some ideas presented in some notes I've been reading, help is greatly appreciated! I've uploaded screenshots of the material I'm referring to below, the last two images are what I'm mainly referencing, and the first few are to provide context...

Previously I posted a problem concerning Electron-neutrino scattering, but as I couldn't describe the problem clearly, so I am trying to post the problem using latex codes to present it in the correct way. For a couple of months, I am trying to calculate the invariant amplitude of the Neutrino...

Hi, Does anyone know of a way I can model the output of a solar still with a specific tilt angle and location (Africa) to give me my desired output value? I've been looking at lots of research papers but the maths is far too confusing for me to even begin to try work it out and I'm hoping there...

For a couple of months, I am trying to calculate the invariant amplitude of the Neutrino electron scattering in the standard model (SM) approach where I am not considering any kind of approximation and using the SM propagator for W Boson and Z Boson. I tried to do as following, find out the...

Homework Statement We recently collected data on a reverse osmosis system for our unit ops lab. The report LERF (Laboratory Experiment Request Form) requests that we ascertain a value of Aw, the water permeability coefficient, for our membrane. We need to perform a T-Test on the data, however...

If you fit a parametrized model (i.e. y = a log(x + b) + c) to some data points the output is typically the optimized parameters (i.e. a, b, c) and the covariance matrix. The squares of the diagonal elements of this matrix are the standard errors of the optimized parameters. (i.e. sea, seb...

There is a proposal for a generalized lattice standard model by Juven Wang and Xiao-Gang Wen. Could this be correct? I've put this under BTSM because it also mentions grand unified models. https://arxiv.org/abs/1809.11171 A Non-Perturbative Definition of the Standard Models Juven Wang...

Hello, I want to develop a pressure regulator model in simscape. The model will be the springloaded direct acting system and the aim is to target outlet pressure, temperature and flow rate by giving input parameters as pressure, temperature, spring stiffness, length and preload, lever(it is...

I'm a former physics student and I've been thinking about an interesting problem that eventually led me to the following thought experiment that I'm having trouble resolving. Imagine a two-compartment system, where one compartment is filled with He gas, and the other is filled with standard...

Hi - having come up blank when searching, I figured I'd ask here: do you know of any (free, preferably open source) planetary accretion models/simulators available for download? I'm primarily looking for solar system formation / evolution rather than planetary geochemistry (although I'd have an...

Homework Statement Two retailers compete on price in a market. Firm 1’s demand depends on both its own price and firm 2’s price as follows: q1 = b – p1 + ap2. Similarly, firm 2’s demand depends on its own price and firm 1’s price: q2 = b – p2 + ap1. Their marginal costs of producing one unit of...

Hello all! I am trying to make a VISUAL model (in C#) to predict lunar and Earth eclipse periods for a satellite that I have accurate ephemeris for. I want to calculate everything in ECEF reference frame. How would a go about modeling this system to the accuracy I'm interested in? I assume I...

Homework Statement For the given circuits, identify state variables and derive a state-space model for each. Assume the input is v(t) and the output is vL(t). Homework EquationsThe Attempt at a Solution [/B] So my issue is that I solved this problem using two different methods. First...

https://arxiv.org/abs/1810.01000 MiniBooNE, MINOS+ and IceCube data imply a baroque neutrino sector Jiajun Liao, Danny Marfatia, Kerry Whisnant (Submitted on 1 Oct 2018) The 4.8σ anomaly in MiniBooNE data cannot be reconciled with MINOS+ and IceCube data within the vanilla framework of neutrino...

Regge-theory succesfully explains the latest LHC ##pp## elastic scattering experimental results and total cross-sections: https://arxiv.org/pdf/1711.03288 https://arxiv.org/abs/1808.08580 Three different Regge-trajectories are needed: one Reggeon, one (soft) Pomeron and one Odderon. The...

Hi, We're studying Contact resistance and the professor has given assignments on contact resistance. But I can't find any books to refer to. Here is one sample question: The books I'm referring to are ones by Donald Neaman, SMZ, Kanos. but none of them have any mention of 1-d or 2-d model for...

Homework Statement A model rocket is launched straight upward with an initial speed of 50.0 m/s. It accelerates with a constant upward acceleration of 1.50 m/s2 until its engines stop at an altitude of 110 m. (a) What is the maximum height reached by the rocket? (b) How long after lift-off...

Homework Statement Homework Equations Halpin Tsai equation:[/B] Voigt model: P*=VfPf+VmPm Vf= volume of fiber/ volume of composite Vm= volume of matrix / volume of composite ζ= estimated parameter Pf, Pm= fiber and matrix properties V_v=1-Vf-Vm The Attempt at a Solution Since there is no...

Hello. I have some questions concerning the Standard Hot Big Bang model versus the Inflationary model. I've read that the Standard model cannot solve the Horizon and Flatness problems but Inflationary cosmology can. Firstly, is this so? Any replies that are pitched at my basic level of...

Hi everyone, I need a little help understanding how periodic reciprocal space applies to the Debye model for solids. Many thanks in advance! If we start with the general derivation of a dispersion relation for a 1D system, with atoms coupled by springs, one gets the following relation $$\omega...

Homework Statement If n=1 is taken to be the reference of the potential energy, what will be the kinetic and potential energy in second excited state of Li2+? Homework Equations E=-13.6z^2/n^2 The Attempt at a Solution I know KE is independent of reference point, so from the formula above...

Related to an engineering project I will be working on. The situation is that essentially I will have a closed cylinder (5.5 in x 26 in) with a small 15mm hole on the side (not on a circular face), which allows the air inside to be at equilibrium pressure/temperature with the outside. Then a...

Hi all, I have trouble understanding some ideas relating to the Debye model. In my text (Oxford Solid State Basics by Steven Simon, page 11), it was stated that Debye wrote the following expression $$\langle E \rangle = 3\sum_{\vec{k}} \hbar \omega (\vec{k}) \ [ n_B (\beta \hbar \omega...

Hi all, I have a few questions related to Debye's model of solids. Any assistance is greatly appreciated. ##\textbf{1)}## My current understanding is that unlike Einstein's model, he views a 1D solid as a chain of atoms similar not unlike a 1D chain of masses coupled with springs. Thus a chain...

We know that the photon is the quanta associated with the electromagnetic field; and we've successfully observed gravitational waves due to LIGO. Is there any corresponding theoretical mathematical description of the graviton?

Homework Statement Consider two pairs of operators Xα, Pα, with α=1,2, that satisfy the commutation relationships [Xα,Pβ]=ihδαβ,[Xα,Xβ]=0,[Pα,Pβ]=0. These are two copies of the canonical algebra of the phase space. a) Define the operators $$a_\alpha =...

Hi all, I was wondering how CERN models their particle results as we see them in images. As I understand it, Heisenberg's Uncertainty Principle tells us that we are unable to precisely observe subatomic or fundamental particles, as the energy would cause its velocity or position to alter. How...

I've been having a sign problem while deriving the permittivity formula using Drude model, and I found out that the problem came from the fact that complex field vectors are expressed with e-iwt, not eiwt, thus producing (-iwt) term when differentiated...

I'm having some trouble understanding some of the steps done in the uploaded paper. I'ts the 1975 paper by Sherrington where they explain the SK model for spin glass. Homework Statement and Homework Equations[/B] Up to equation 5 I understand all steps. I used J_0 = J_0 / N and J^2 = J^2 /...

Hi, I've been studying the quark parton model recently and all seems fine at first. However, there's just one thing bugging me right now. So in the quark parton model it is assumed that inelastic lepton-hadron scattering can be explained by elastic lepton-hadron scattering, but how can it...

I am trying to do some calculation based on a k.p model of GaN proposed by S. Chuang [Phys. Rev. B, 54, 2491]. It is a 8 by 8 Kane model with basis functions: The 8 by 8 Hamiltonian contain first order of k is where ##{k_ \pm } = {k_x} \pm i{k_y}## the reciprocal space and high symmetry...

Hi, Just wanted to see if I understood the meaning of Generalized Linear Models: In the case of Standard ( "Non-generalized") Linear models, a dependent variable y is a linear function of a dependent variable x. In a Generalized Linear Model (GLM), a dependent variable y is linear in some...

If we use a probabilistic model of QM, is there still room for determinism? If we don't have knowledge of the exact outcomes, can there still be underlying determinism in such a model? I am aware there are probabilistic and deterministic models available for QM. Does that mean QM could be...

Not 100% sure this thread belongs in this section, sorry if it's out of place. I was trying to run a simulation of a 2D Ising model; i thought everything was going fine until I started to look at the numerical results and I noticed that I get some wild fluctuations in my results; as an example...

Does anybody know who first drew (not just described but actually drew, even roughly) a model of the atom like the one below, and when: I'd appreciate it if anybody can point me to an evidence.

Hi there I am a high school science teacher and I want to present my senior classes with a model of the fundamentals of the physical world to serve as a mind map for us when we reach each topic. I have started by creating the one below and then realized I may have left off momentum...is momentum...

I am trying to model a real heat exchanger in simulink. I don't have the geometry data. But I have UA curve with me. If I have developed the model with UA curve, will it be dynamic in nature?

Hello, I am trying to do the following regression model; Y = N + T + F + NT + NF + NTF + error Y= Grams of seed N= Number of fruit T= Type of fruit (2 types, alpha) F= Field number (3) I have tried putting this in MiniTab and I can't get this set up correctly. Assistant> Regression>...

Hawking and Hertog's new paper "A Smooth Exit from Eternal Inflation?" does away with the infinite multiverse of Hawking's previous theory and proposes a cosmology that predicts "a simpler and finite universe". But I can't figure out the extent of this reduction to a "simpler and finite"...

Hello, I am completing a research project for differential equations class. I am to derive Kepler's three laws and then compare the results of the derivation with real-world data. For Kepler's second law (a planet sweeps out an equal area in an equal time), I was hoping to find orbital data for...

I am going through Almheriri's article about " Models of AdS##_2## and I am stuck on a derivation. I think they make some kind of assumption which I don't understand. What I am trying to do, is to compute the equation of motion by varying the action with respect to the metric. Unfortunately I...