2d Definition and 1000 Threads

Hi everyone, Say I have a 2D one loop integral of the form $$ I^s_n(\Delta)=\int d^2 l \frac{(l^2)^s}{(l^2-\Delta)^n} $$ Using that ##1 = \frac{1}{2} \partial_\mu l^\mu##, I can relate say $$I^1_2(\Delta)=I^0_1(\Delta)$$ + total derivative term. In dimensional regularization one usually...

It is a classic 2DE quantum well problem. I do not understand few things. I haven't seen the solution anywhere on the new, so this is why i ask here. It is a quantum well - Lx is it's dimension along x-axis Ly is it's dimension along the y-axis.There is a potential as in picture let's call it...

I have 2D elements distributed in a space of [-4, +4] and want to convert any point in the 2D space to a 1D real-valued number 0~1.0 such that 1st quadrant [+, +] should have higher values (importance) suppose 0.4~1 , 2nd and 3rd quadrant [+, -] and [-, +] should be next 0.2~0.4, and the 4th...

Homework Statement Two balls of equal mass m undergo a collision, the velocities of the balls make angles of 25.5° and -45.9° relative to the original direction of motion of the moving ball. (a) Draw and label a diagram to show the balls before and after the collision. Label the angles...

Homework Statement Car 1 weighing 1000 kg crashes into the rear of parked car 2 weighing 1100 kg and stops. Car2 moves ahead 2 ms2. What is the velocity of car1 at impact? Homework Equations (m1v1+m2v2)=(m1v3+m2v4) The Attempt at a Solution (m2V4)/m1 (1100*2)/1000 2.2ms2=...

I decided to make the switch from C to C++ and I'm having trouble with vectors. In C, I prefer to use dynamically allocated arrays when doing multidimensional arrays. But in C++, I know that there is the new function which replaced malloc. I read that when dealing with multidimensional arrays in...

Can I graph the phase space of a 2D harmonic oscillator in R^2 in the following way? Let one vector in R^2 represent for position of the point mass and let another vector represent momentum. Together these two vectors in R^2 can represent a single vector in R^4? Do we loose any "information" in...

Homework Statement I have boundary conditions on my heat equation ## \dot{T}(x,t) = T''(x,t) ## ## T(0,t) = T(L,t), ## ## \frac{\partial T(0,t)}{\partial x} = \frac{\partial T(L,t)}{\partial x} ## Then at ## T= 0## ## T(x,0) = 1 ## for ## 0<x<L/4 ## ## T(x,0) = 0 ## for ## L/4<x<L ##...

Homework Statement ## \frac{\partial^2 V}{\partial x^2} +\frac{\partial^2 V}{\partial y^2} = 0 ## it's defined for ##V=0 ## for ## x=0, 0<y<b##, ## x=a, 0<y<b##, ## y=0, 0<x<a## ##V=V_0 x/a ## for ## y=b, 0<x<a## Homework Equations None. The Attempt at a Solution I've got ##V(x,b) =...

hello guys, I have a CSV file with hyuge set of data devided into 3 cols. Y position X position and corresponding intensity values. I want to plot the image , my thesis is laser- microscopy. so a 2D plot ( density plot ) based on these values. The following is what I have tried so...

Hi all, it seems that there is a rule of thumb used by some researchers looking at nonlinear systems whereby they determine the stability of fixed points based on the product of the gradients of the null clines at the point where they intersect. in particular if the product of the gradients...

It's problem #5 on this homework set: https://docs.google.com/open?id=0B9c8sp75B5ZRMHAxYXB3MWdhYk0 I can calculate (\pi/4)(n1σ1 + n2σ2 + n3σ3) easily, but I have NO clue how a matrix M = exp[(\pi/4)(n1σ1 + n2σ2 + n3σ3)].

I posted this first in the homework section, but no one answered it. I figured this might be a better section... I have multiple 1D data sets, let's call them data1, data2, data3, etc. Each data set has the same number of entries. Each one is either a row or a column (I can just use...

Homework Statement I am trying to rotate a 2D array of type string. I am not sure what the problem is with my function. Flipping does occur but for some reason, it's not by 90. Homework Equations The Attempt at a Solution The program consists of a function and the main. Here's...

Homework Statement I have multiple 1D data sets, let's call them data1, data2, data3, etc. Each data set has the same number of entries. Each one is either a row or a column (I can just use Transpose[...], so same] and when I use the ListPlot[] function, I get a graph where the vertical axis...

I want to create a programming project that involves creation of a discrete autonomous system. It is very similar to cellular automaton as the simulation environment is composed of 2D cells on an unbounded grid. Cells have attributes assigned to them which makes them behave and function together...

Homework Statement I am attempting to transfer the data from a file into a 2D vector array. The data look like this: 1 2 3 4 5 6 7 8 9 However, the dimensions must be detected dynamically. Homework Equations The Attempt at a Solution There are two files in this code, but I attempted to...

Im trying to write a MATLAB code for 2d transient heat transfer. The problem is a titanium block in the shape of a rectangle is staring at a specified temperature and is being exposed to a much hotter surrounding temperature. The dimensions, coefficients of heat transfer, and temperatures are...

The Green's functions for a 3d wave are like δ(r - ct)/r -- so if you have static source at the origin that is turned on at t=0, you get an expanding ball around it of radius ct, with strength 1/r. If you look just at the XY plane, you see an expanding disc of value 1/r. Similarly, if you...

Homework Statement Given a steady-state heat transfer for a 100mx100m plate, to be discretized to 6 nodes, governed by a heat tranfer equation: U_xx + U_yy = 0 Given dirichlet boundary conditions: U(0,y)=50, U(100,y) = 100,, neumann boundary: U_y(x,0)=0, U_y(x,100) = 0. Find the...

Hi guys. Badly need some help. We were given this 2D heat equation BV problem. On the square plate, values on all four edges are given (2 are Neumann, 2 are Dirichlet). And we are to solve this problem using FDM, on a 5point stencil. So I used FDM approximations to derive the formula for the...

Homework Statement For a lab, I have performed a completely inelastic collision using 2 masses. One mass is 0.583 kg, and the other is the unknown we have to find. Using an air table, I was given the dots to show the movements of the objects as they intersect and them move together. I have...

Homework Statement Let a particle of mass 2M have an initial velocity of v0i (the i merely indicating it is traveling on the x axis) and undergo an elastic glancing collision with a particle of mass M initially at rest. After the collision, the M particle moves off at an angle of 45° above the...

What's it called when a 3D shape can be made of 2D surfaces of all the same shape and dimensions? To make a cube, I can use 6 4-sided-squares (of course they're 4 sided) To make a pyramid (3 sided), I can use 4 3-sided-triangles I can do this with pentagon as well (i don't know what the...

Homework Statement I'm trying to find normalised 2D coordinates for a point (Px,Py,Pz) that lies on a planar surface, which is defined by straight lines between 4 points c1-c4 (numbered anticlockwise). Homework Equations General vector equations The Attempt at a Solution Suppose...

Hi All, My first post here. As far as I've understood there are problems with massless states in two dimensions. In the problem I am working on I have a 2D (non linear) sigma model with a lot of symmetries. The worldsheet fields come as heavy and massless. My main interest is to...

Homework Statement You are a pilot on an F-16, waiting on a still aircraft carrier. You must fly to another aircraft carrier 1450 at 45* from your position, moving at 56 km/h due east. The wind is blowing from the south (To the north) at 72 km/h. Calculate the heading and air speed needed to...

Hi everyone, I am working on a project for the development of a 2D Unsteady Panel Method for Airfoils. As often already suggested in this forum I have been using the book "Low Speed Aerodynamics" which has helped me a lot to produce the Steady State solver (I am writing the code in Matlab at...

Hello everyone! I've found a physics problem that i don't know the solution of(maybe because of my limited knowledge). The problem is something like this: Let's say an object travels in a circular path from P to Q and Q to R in which P, Q and Rare not the center of the circle(because P, Q, R...

Homework Statement Having trouble with code as seen by the gaps left where it asks me to add things like the coefficient matrices. Any Numerical Conduction MATLAB wizzes out there? A long square bar with cross-sectional dimensions of 30 mm x 30 mm has a specied temperature on each side, The...

I would like to know the distribution of z as the euclidean distance between 2 points which are not centred in the origin. If I assume 2 points in the 2D plane A(Xa,Ya) and B(Xb,Yb), where the Xa~N(xa,s^2), Xb~N(xb,s^2), Ya~N(ya,s^2), Yb~N(yb,s^2), then the distance between A and B, would be...

Hi, I'm currently using the Monte Carlo Metropolis algorithm to investigate the 2D Ising model. I have an NxN lattice of points with periodic boundary conditions imposed. I was wondering if anyone could explain why the sharpness of the phase transition is affected by the size of N? I.e...

I am trying to plot the following function: \sigma(r, \phi) = \frac{3r^2}{\sqrt{1 - r^2}} e^{i(2 \phi - \omega t)} where \sigma is a surface density, r is radius, and \phi is azimuthal angle. It is supposed to yield a "bar shape" for a galactic disk, but I'm not sure how to go about...

I have a function of two variables, f(a,b). I want to create a series of 2D plots (on the same plot) of f(a,b) vs a, for a=1 to 10, for a set of discrete values of b (e.g. b=10,20,50,100). Is there a simple way to do this? Plot3D works, but I cannot find how to do it in 2D. DN

Hi, I have a vector function (momentum \vec{p}(x,y,z)=\vec{p}(\vec{r},z) for \vec{r}=(x,y)) and need to transform it, also I use the Fourier transform F(\vec{p})=\int_{-\infty}^{\infty} \int_{-\infty}^{\infty} \vec{p}(\vec{r},z) exp^{i \vec{\chi}\cdot \vec{r}}d\vec{r} and then when I have...

°Homework Statement A pilot wishes to fly to city A, 800km north of the present location. The plane is capable of an air velocity of 300km/h. There is a wind blowing 120 km/h [S40°W] a) if she flies directly to city A, what will be her observed ground velocity? b) what should her orignal...

How does on calculate the expectation of the position operator x in a 2D infinite potential well (in the xy plane)? Do we only work with the Psi to the Hamiltonian in that particular coordinate when finding <Psi|x|Psi>?

Hello everyone. I would like to hear some suggestions on minimizing a function. I have discrete 2D function (a grid, where each (x,y) point have some value), where I know only extreme points (more specifically - ridges. http://en.wikipedia.org/wiki/Ridge_detection). I want to reconstruct...

Hi I am succesfully using NDSolve to find the solution of a 1D equation of motion: solution = NDSolve[{x''[t] == -200, x[0] == 0, x'[0] == 100}, x, {t, 0, 1}]; ParametricPlot[{x[t], x'[t]} /. solution, {t, 0, 1}, PlotRange -> {{0, 100}, {0, 100}}] This is a particle decelerating constantly in...

So we were taking measurements for an experiment in our radio astronomy lab. For the first part of the experiment, we recorded the intensity of a far away point source ( the signal from a TV satellite was used for the point source ) detected by commercial satellite dish and receiver. When we...

I'm a game developer and I have an idea to make something heat up and cool off and I would like to use realistic style formulas to do the math. Instead of making it add dramatically over time. I basically need a formula for adding and removing heat from a 2 dimensional vector based on...

The problem given is a perturbation on the two dimensional harmonic oscillator where the perturbation is simply: H'=-qfy. It seems that all of the elements of the matrix H' are zero and so constructing a diagonal matrix in the subspace is eluding me. Any ideas?

Homework Statement Three forces in the x-y plane act on a 2.6 kg mass: 13.3 N directed at 65°, 7.6 N directed at 160 °, and 10.1 N directed at 236° . All angles are measured from the positive x-axis, with positive angles in the Counter-Clockwise direction. Calculate the magnitude of the...

Hi! I have a function for which I need to calculate or at least approximate the 2D Fourier transform, that is, the Fourier transform applied twice on the function but on different variables. The function is tanh(w)/w, where w is the absolute value of the vector (wx, wy). So the function can be...

Hi Say I have a data set (x_i, y_i) such as of the form { {4.4077, 8.41282*10^-7}, {9.39964, 3.3636*10^-6}, {14.3781, 7.56237*10^-6}, {19.3462, 0.00001343}, {24.3073, 0.0000209557}, } The first coordinate is time, the second a weight. The sum of the weights equal 1, so I am...

Homework Statement A square rectangular pipe (sides of length a) runs parallel to the z-axis (from -\infty\rightarrow\infty). The 4 sides are maintained with boundary conditions (i) V=0 at y=0 (bottom) (ii) V=0 at y=a (top) (iii) V=constant at x=a (right side) (iv) \frac{\partial...

Homework Statement Mass m1, moving to the right, collides with mass m2, which is at rest before the collision. The masses are m1 = 0.1 kg and m2 = 0.2 kg. The scattering angle of m1 will be 30 degrees above the horizontal. a) Calculate the recoil angle phi of m_2. b) Calculate the recoil...

Hi guys, I am currently writing my dissertation on Graphene and I am investigateing how graphene remains stable, contradicting existing well established theory which states 2D materials cannot exist independently. With the main area of investigation looking at possible lattice distortions...

I am currently looking at constructing a model of a 3D printed item based on a sequence of images of each layer of the print. At the moment the sequence of images are transformed to black / white and run through a Moore Neighborhood algorithm and then a voxel representation of the printed...

Homework Statement Dr. Evil runs out to his car which is parked at the bottom of a hill that is inclined with the horizontal at 20(degrees) and blasts up the hill at an acceleration of 6 m/s2. James Bond runs out behind Dr. Evil to a mortar that is located conveniently exactly where Dr...