Model Definition and 1000 Threads

Homework Statement Hey guys! I'm not convinced by what I obtained so far, please tell me whether I'm in the right or wrong direction. The Hamiltonian has the form ##H=-h\sum _i s_i## where ##s_i=\pm 1## and ##h=kT##. 1)Calculate the partition function and the Gibbs free energy. 2)Calculate the...

I am trying to model an FPGA FM radio demodulator in Python. I will have a mixer that converts an FM channel to 36MHz IF, and I plan on undersampling this IF signal. If in the digital world (my Python model), I have a high sample rate FM signal at 1.2MHz, should I be able to resample to a...

This is a question from Altland and Simons book "Condensed Matter Field Theory". In the second exercise on page 64, the book claims that if we define \hat P_s, \hat P_d to be the operators that project onto the singly and doubly occupied subspaces respectively, then at half-filling the...

Homework Statement Homework Equations r_d= V_T/I_D, V_T=25mV The Attempt at a Solution i alreayd find the operation of diodes, D1 off and D2 on (2nd circuit). the current through this diode i also calculate as 34mA, also r_d=0.7353 ohm. I am having trouble using incremental model, in my book...

Hi, I'm planning to start my Master programme this december. I am very interested in philosophy of logic. And i am inclined to read more proof theory rather than model theory. And i really wanted to engage in proof theory as my first reading materials towards mathematical logic area...

I have built a model boat, ( http://schoolroad.weebly.com/rpgmodel_11.html ) and am trying to find out the amount of Power - maybe in Watts, that it takes to propel it at different speeds while it is running on the water. I have a rough sketch of the mechanism principle attached. When the...

Hello, I am trying to get a better understanding of how oscillator circuits (clapp, hartley, colpitts etc) work, so I have been trying to solve the differential equation for a very simple one--the one most the way down the page here...

Hello, I'm thinking about the wavelength of a freely propagating photon vs. a freely propagating electron. For the photon, we have the classical picture of oscillating E and B fields perpendicular to the direction of propagation, and we call the wavelength of the photon, which can be...

I was looking at this old chart (before the standard model was completed) and this thing with Kaon notations was confusing. So I understand that the top right number on a particle denotes charge, but what is subscript? Does that denote the number, as in which exact particle it refers to? Because...

I want to derive some equations for a 2-D airplane's motion, specifically when it lifts off and lands. Can someone show me where I can start and how I can use differential equations to develop equations like the speed/position of the airplane in its x and y components? Also, if anyone is...

Homework Statement I need to write \begin{align*} N_{k+1} = \frac{\lambda N_{k} }{1+aN_{k} } \end{align*} in the form \begin{align*} N_{k+1} = N_{k} + R(N_{k})N_{k} \end{align*} Homework Equations As above The Attempt at a Solution I know that \begin{align*} N_{k+1} = N_{k} +...

I’m interested in your views on whether any significant thrust could be obtained using the cooling air and exhaust gases from a model aircraft engine. International class control line speed models (known as F2A) achieve speeds of around 300 km/hr using 2.5cc engines and tuned pipe exhausts that...

hello. I have a MATLAB skeleton provided because i want to model a distribution with a circular geometry. all in all, i want the 3d graph of the code to be some type of cylinder. This is the code: % flat step condition for ii=1:nHi, for jj=1:nHj, if (X(ii)/R_P)<1 &...

Why is it such a big deal? According to the "modern" (Wilsonian) viewpoint, non-renormalizability is not such a "sickness" of a quantum field theory, as long as one adopts the viewpoint that the theory is not UV complete, aka, the theory is simply an effective field theory with a finite cut-off...

Would it be possible to just get a swirling plasma in an acrylic tube kind of like the arc reactor in iron man? I'm not talking about anything close to the temperatures or pressures required for fusion just kind of a demo piece to show the general idea.

Can I prevent setting up standing waves in my COMSOL model? I'm using integration over two opposing faces to get the pressure at the 'outlet' - but it seems that no matter what I do to prevent the standing waves, they won't go away. Any help would be great, Thanks

I've done some research, and I've looked at the derivation of the diffusion equation, but I don't want to reproduce even a more simple version of it. I'd like something that can I do almost exclusively myself. The point of this is not to plot some graphs, and extract some line of best fit or...

I have some questions about this paper:http://users.phys.psu.edu/~radu/extra_strings/freedman_sigma_model.pdf In section 3, they renormalize the bosonic non-linear \sigma model at one loop level. The action is given by I_B[\phi]=\frac{1}{2}\int...

Hello guys, I have a project I intend to embark on,actually it a helicopter,but I still can't figure out the best type of motor to power the blades of my design. I need something light,small and POWERFUL. I look forward to your contribution. Thanks in advance.

Recently, I saw a video on Introductory Quantum Mechanics. Here's the link : https://www.youtube.com/watch?v=5Gnqpbge3Yk I failed to understand the explanation of de Broglie's model. He mentions that the waves interfere with each other but how do we know the properties like amplitude etc. of...

I try to import a sab. Modeltyp in Ansoft 15. but i receive an error that translation for the model is failed or saved file is from a later version. how can i fix the problem. Thank you .

I have a list of scores between 0 and 1 generated by an information retrieval system - 1 being very relevant and 0 being completely non-relevant. I do not know whether the scores correspond to relevant or non-relevant items or not but I do know that the distribution of scores is generated by a...

Hi Everyone, I was curious as to what the most current model in solid state physics is. I've studied the Einstein and Debye Models in Stat Mech, as well as free electron and tight binding models in an intro solid state class, but these models are rather old(which does not imply they are...

i searched Steven weinberg in google scholar. it returns many articles but "a model of leptons" why does "a model of leptons" not appear in google scholar? is there some mistake or some reason for it not to appear? it seems odd that the famous articles is not found Phys. Rev. Lett. 19, 1264...

In theoretical physics, why is the mathematical model favored over the mechanical model? Awhile back, I posted a thread asking about what each theory posits as real. For example, quantum field theory might limit the set of real things to fields, field quanta, the universe, and causality. It...

I am performing Modal analysis on a fairly simple structure (a square aluminum rod with some pillars attached to the top of it) and need to get some basic modal analysis results. Making a solid aluminum piece would be rather expensive and time consuming to design and then mill out, so the...

Many of you are familiar with the catapult launched profile fuselage gliders that are sold in hobby stores. Since these tend to rather fragile, I am designing gliders with better durability out of card, and also with a full fuselage. These will have a 20 cm wingspan typically. Given that low...

Question: Develop a model for producing a repeating pattern of 8 waves, with 6 smaller waves of approx. the same size and the second and sixth waves much larger. The sketch below gives a general indication of the eight wave pattern. (Sorry for large image) I would like to know how to "take...

Homework Statement Homework Equations y=30\sin(\dfrac{2\pi}{20}t)+270 General principal solutions: t=\left(\dfrac{\arcsin(\dfrac{1}{3}) 20}{2\pi}\right)+20k, k\in \mathbb{Z} t=1.08173+20kGeneral symmetry solutions: t=\left(-\dfrac{(\arcsin(\dfrac{1}{3})-\pi)20}{2\pi}\right)+20k, k\in...

Hi everyone. I am not a physicist or scientist but this is a question I have pondered for a while now. Everytime I see a model of how large bodies (eg Earth and sun) bend the planar representation of space (creating a "cup" or "dip") I always feel that this is not completely representative...

Hi guys, I have the idea of putting together a model collider that fires two smashable objects (eggs or whatever) at each other and show a high speed camera footage of the objects hitting each other - this is all as an analogy of what the hadron collider does at CERN. Any ideas what I...

Hey guys, I've recently read about the Tavis-Cummings and Dicke models and I got a little bit confused about them. They are suppoused to model N identical atoms interacting with a one-mode EM field, however the atomic operators are defined in the basis (for the case of two atoms)...

Why is Bohr's model of an atom not able to explain the spectrum of atoms other than hydrogen? Can you give an example? :what:

Hello, well, I am totally new to this section of physics so my question may sound ridiculous, but here it is: When I was reading about the Bohr's atomic model, I learned about the Bohr and Rydberg equations (E=-2,18*10^18*Z^2/n^2 J and 1/λ=RZ^2(1/n1^2-1/n2^2) as well as their proofs. Then I...

I have a problem with the calculus of magnetic moment of Li-6. The configuration of protons is 1p_{3/2}, and the neutrons' one is the same. I have to add the magnetic moment of uncoupled proton and uncoupled neutron. I use the following formula for J=l+\frac{1}{2} (J is the particle...

I am looking for an equation that correlates material failure and collision speed; so that I can better understand the effects of size and speed on model airplane crashes. Is there an equation that correlates an object's length and speed to material failure, for one-dimensional elastic...

Hello everyone. I am world-building for a fantasy setting. I've had an idea and I'm not sure if it's feasible or not. I'm trying to model a non-standard world type and I wanted to see if I'm on the right track. The idea is for a ring world. The outside is habitable. I've already got a...

In case you have the Kahler and super- potential K,W: K(T,S,C) = -log (S +S^{*}) -3 log ( T+ T^{*} - C C^{*}) W(T,S,C)= C^{3} + d e^{-aS} +b with T,S,C chiral super fields, b,d complex numbers and a>0. I tried to calculate the local F-terms arising from this. The local F-terms for the i-th...

Hi! I'd like to understand how to model consumer demand given a price I set for a good. Therefore for a specific good I'm given the current prices of competitors and maybe some historical values for number of goods sold by competitors and me at a specific price at previous times. I would...

==from conclusions section on page 4 of Barrau Linsefors June paper== V. REBIRTH OF THE UNIVERSE AND TESTS OF THE MODEL In the far future, huge patches of our universe, with radii larger than the Hubble scale, will be completely empty. They will be pure dS spaces. If the model suggested in this...

In the standard model gravitron is a particle but Higgs boson is not. The Higgs field causes particles to acquire mass. Mass generates a gravitation field. Is gravitron is in any way related to Higgs boson? Is the Higgs field any way related to gravitation field?

Homework Statement A collection of fixed scatterers ('trees') are placed on a plane at random. The trees are oriented squares with diagonals along the x- and y-directions (cf attached picture). The number of trees per unit volume is n, each side is of length a, and na^2 << 1. There are...

Hi guys, I am not economist, but can anybody tell me whether there is a mathematical model for growth in free market economy without state intervention? Where can I look them up? Thanks.

Greetings again, So I realize my last thread: https://www.physicsforums.com/showthread.php?t=757685 became chaotic with my thoughts and un-clear writing. I've re-did the work to make it easier for people to understand my thought process. The two questions are as follows: 7)Calculate the...

Okay, I am in need of some guidance: 7)Calculate the wavelength that corresponds to an emission of energy of 1.977x10^-19 J. Okay, well here is my thought process initially: Change in Energy = hc/wavelength. First question: Is 1.977*10^-19 THE change in energy? OR is that the Energy...

Why do some education systems still continue to teach Bohr's model even though it's seen to be incorrect?

Homework Statement [/b] Develop a mathematical model that would lengthen the time until the shock stabilised by the given time. T= 2.51 show mathematical analysis of the situation d(t) = -5e^(-5t) cos (10t) is the original equation for a deflection of a rod in centimetres where t is time...

For the past week or so, me and a buddie have been trying to figure out how to make a mini-hoverboard kind of this, now it doesn't even have to look like a hoverboard we just want it to be able to get off the ground with 2 fans. What we were going to order was all this stuff...

Hi. I've been reading that if one places a Dp brane in a 10d space then it's possible to have a string with [11] Chan-Paton index i.e. a string that starts and ends on the same Dp brane. Since the separation of the brane with itself is 0, this string corresponds to a massless particle. Why is...

I am planning to do some work on quark fragment into hadrons, and I have heard some models like Lund Model, feynman-field model and so on. Is there any good review articles on the topic of fragmentation model? (Recent years is better) Best Regards!