Recent content by Sistine

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    Particle Physics Integral Calculation

    Yes I read the edit part of your post, but in my lecture notes there was nothing said about approximation by the Yukawa potential, the integral was just given as I stated it above. Is the integral an approximation? It partially works out when integrated. (also is it related to the first born...
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    Particle Physics Integral Calculation

    Thanks for your reply, I tried integrating over \mathbb{R}^3 but my integral does not converge for 0\leq r<\infty i.e. integrating \int_0^{2\pi}\int_0^{\pi}\int_0^{\infty}r e^{ikr \cos\theta} \sin\theta dr d\theta d\phi Doing the \theta integration first I get...
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    Particle Physics Integral Calculation

    Homework Statement In calculating the quantum mechanical amplitude for the Coulomb potential (scattering of say \alpha particle off a massive particle of charge Ze), I came across a Fourier transform which I could not calculate. If U(r)=\frac{2Ze^2}{4\pi\epsilon_0 r} then...
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    Application of Liouville's Theorem (Complex Analysis)

    Homework Statement Prove that if f is a meromorphic function f:\mathbb{C}\rightarrow\mathbb{C} with |f(z)|^5\leq |z|^6\quad\textrm{for all}\quad z\in\mathbb{C} Then f(z)=0 for all z\in\mathbb{C} Homework Equations Liouville's Theorem A bounded entire function is constant. The...
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    Differential Geometry Question

    Perhaps your right. The image of the Gauss map at a point is perpendicular to the tangent space at that point , so that no linear combination of \partial_1\sigma, \partial_2\sigma could ever represent N at that point. However is it possible to represent the map N:R2->R3 as a matrix? I'll try to...
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    Differential Geometry Question

    Homework Statement Consider the following parametrization of a Torus: \sigma(u,v)=((R+r\cos u)\cos v, (R+r\cos u)\sin v, r\sin u) R>r,\quad (u,v)\in [0,2\pi)^2 1. Compute the Gauss map at a given point. 2. What are the eigenvalues of that map in the base...
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    Variant of the Maximum-Modulus Principle

    Homework Statement Show that the maximum principle holds with \phi :\mathbb{C}\rightarrow\mathbb{R},  \phi(z) = (\textrm{Re}(z))^4 + (\textrm{Im}(z))^4, in place of the modulus: If U \subset \mathbb{C} is open and connected, f : U \rightarrow \mathbb{C} is holomorphic and p \in U...
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    Parametrized Surface Problem

    Homework Statement If a regular surface can be parametrized in the form s(u, v) = a(u) + b(v) where a and b are regular parametrized curves with (u,v) in some domain D\subseteq\mathbb{R}^2, show that the tangent planes along a fixed coordinate curve of D are all parallel to a line...
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    Electric Field inside a solid of uniform charge density

    I have thought again about the problem. I know that all the charge within the solid will work to repel itself so that the all the charge tends towards the surface. So that by Gauss' law the electric field within the surface is zero. But I still don't know what the electric field will be on the...
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    Electric Field inside a solid of uniform charge density

    Homework Statement What is the electric field inside a a solid of uniform chage density i.e. \mathbf{E}(\mathbf{r})=\frac{1}{4\pi\varepsilon_0}\int_V\rho(\mathbf{r}')\frac{\mathbf{r}-\mathbf{r}'}{|\mathbf{r}-\mathbf{r}'|}dV' What is the electric field at \mathbf{r}'=\mathbf{r} if...
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    Parametric Equations for Tank's Continuous Track: Explained and Demonstrated

    Homework Statement A tank is traveling in a straight line we look at the side on view of the tank and consider its continuous track in contact with the x-axis. Its wheels have radius R and the distance between he centers of the wheels is L (The continuous track is wrapped around the wheels)...
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    Integral of Complex Rational Function over Large Contour

    I tried letting the radius of the contour go to infinity but I got 0 as my final answer. Numerical methods seem to point to the conclusion that the integral is non-zero, so I don't think this is correct. I know that \int_{C_{30}}f=\int_{C_R}f\quad R>30 but is it true in the limit as R\to\infty?
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    Integral of Complex Rational Function over Large Contour

    Homework Statement Compute the integral \oint_{|z|=30}\frac{dz}{z^9+30z+1} Homework Equations Residue theorem for a regular closed curve C \onit_C f(z)dz=2\pi i\sum_k\textrm{Res}(f,z_k) z_k a singularity of f inside C The Attempt at a Solution I'd rather not compute the...
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    Entire Functions Bounded by Exponential Growth

    I tried applying schwarz lemma to |f(z)|\leq |e^z| i.e. \left|\frac{f(z)}{e^z}\right|\leq 1 But this did not give me much information about f. What other Theorems from Complex Analysis could I use to gain information about f?
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    Entire Functions Bounded by Exponential Growth

    Homework Statement Find all entire functions f such that |f(z)|\leq e^{\textrm{Re}(z)}\quad\forall z\in\mathbb{C} Homework Equations \textrm{Re}(u+iv)=u The Attempt at a Solution I tried using Nachbin's theorem for functions of exponential type. I also tried using the Cauchy...
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