Computing Definition and 683 Threads

Homework Statement Let C be the arc x=t^2, \space y=2t, \space z= \sqrt{4+3t} for t \in [-1,0] Evaluate the line integral : \int_{C} z^2dx + \sqrt{x}dy - 4xyz dz Homework Equations \int_{C} f(P) dx = \int_{a}^{b} f(P(t)) x'(t) dt for t \in [a,b] The Attempt at a Solution So...

I have never—and I really do mean never—seen an article in the mainstream press about quantum computing that didn't get it completely wrong. I don't just mean "over simplified"—physics is highly technical and ignoring important details for lay audiences is just a fact of life. I mean that they...

Link: http://research.microsoft.com/en-us/projects/dna/ As I was experimenting around with that simulator, and realized that the language have some similarities with the assembly language, I asked myself: "Are programming languages such as C++ (or at least some of its concepts) will still...

Suppose I have the following transformation: u = \frac{x}{x^2+y^2+z^2} v = \frac{y}{x^2+y^2+z^2} w = \frac{z}{x^2+y^2+z^2} Is there a fast way to calculate the determinant jacobian without having to deal with the whole 3x3 determinant? I noticed that the inverse...

Homework Statement Show that three controlled-NOT gates (for a 2 qubit system) can be combined to form a SWAP gate. The control qubit alternates between the 2 qubits for each consecutive c-NOT gate. (The diagram is Figure 5 of the following notes...

says that computing power at an economic price roughly doubles every year. this relies on the fact that we can stuff more transistors into smaller spaces. we won't reach quantum limitations until atleast 50 years. where will we (humans) be by than?

Hi all, I was just wondering if there has been research into computing using electromagnetic waves. It seems to me like a sealed off box with internal EM pluses could be used to mould waveforms through interference, which would act as logic gates to provide useful computational results. Would...

Homework Equations e=(product of number of driving teeth)/(product of number of driven teeth) e=(n_{out}-n_{arm})/(n_{in}-n_{arm}) The Attempt at a Solution e=(N_{p1}/N_{s1})*(N_{s2}/N_{p2}) e=1.25926 e should be 0.7941 however From there out it seems pretty trivial. I just need...

With the phenomenal speed to be expected from quantum computers in the future, todays encryption techniques such as RSA will be pretty much useless. A quantum computer could factorise 600bit+ numbers in a relatively short period of time. Aside from Shor's algorithm, are there any other...

Hi there! I'm currently having great fun using numpy/scipy in python for astronomical data analysis. (I've been using C for this before, but it takes too much time to implement simple things that are in numpy/scipy already) Recently I've been told that most of people are using C or Fortran...

Homework Statement Consider a universe where there are two types of matter: dust and curvature. The density of dust evolves with time as ρdust(t) = ρ0R(t)^(−3) and curvature evolves as ρcurvature = −kR(t)^(-2) where ρ0 and k are constants. The Friedmann equation is: H^2 = [(8∏G)/3][ρdust...

Does anyone have a good book or reference on computing riemannian connections. I'm looking at Do Carmo and can't find any examples. For ex. If X = y(d/dx) + x(d/dy) + w(d/dz) -z(d/dw), Y = z(d/dx) - w(d/dy) - x(d/dz) + y(d/dw), Z = w(d/dx) + z(d/dy) - y(d/dz) - x(d/dw) being the classical...

Homework Statement Density of f_x (x) = 4x^4 for 0<x<1 Y=(x-1/4)^2 Z= X^-2 Determine density of Y and Distribution of Z Homework Equations The cdf of f_x (x) is invalid since F_x (x) = (4/5)x^5 so the limit to infinity does not equal 1 as a cdf should have. Am I missing...

1. Jupiter radiates more energy than it receives from the Sun by 8.7x10-10L0. Jupiter's radius is 7.0x109cm and its mass is 1.9x1030g. Compute its thermal time scale. Could gravitational collapse power this luminosity for Jupiter's entire lifetime of 4.5 Gyr? 2. Kelvin-Helmholtz (aka...

Check this out: http://www.kickstarter.com/projects/adapteva/parallella-a-supercomputer-for-everyone. It's a project that aims to create open source hardware for scalable parallel computing. If you pledge $99, you get one of the computer they are building. In case anyone is wondering about...

Homework Statement I attempted this problem, and i have a midterm tommorow. I thought my approach was correct but I don't have a clue if it actually is. I drew a simple right angle triangle according to the information given in the question. A ball swings in a vertical circle at the end of a...

Homework Statement The following is Problem 1-13 on page 23 from Electrical Engineering Fundamentals, 2nd ed., by Vincent del Toro: "In the configuration shown in Fig. P1-13 the coil has 100 turns and is attached to the rotating member which revolves at 25 \frac{rev}{s}. The magnetic...

I am currently majoring in Electrical Engineering with a deep interest in quantum computing and quantum cryptography, the former being my greater passion. I'm certain that most, if not all, of those working in the field of quantum computing have at least a PhD in Physics. The same goes for...

[b]1. consider this wave function ψ(x)=(√(30/L^5))(L-x) if 0≤x≤L and 0 else [b]2. Compute the expectation value of the momentum. Compute the expectation value of the kinetic energy. Compute Δ p⋅Δ x...

Hi, I found this great free online class about Quantum Computing on coursera.org. The class is called "Quantum Mechanics and Quantum Computation" taught by Umesh Vazirani. - https://www.coursera.org/course/qcomp - *Umesh Vazirani is the Strauch Distinguished Professor of Electrical...

Homework Statement Suppose T is an equilateral triangle on the sphere of radius R = 1. Let \alpha denote the angle at any of the three vertices’s of the triangle. (Recall that 3\alpha > n.) Use the result of the last problem on the previous homework and the inclusion - exclusion principle...

Hello, first off, I'm not sure if i have placed this question under the correct forum, so i apologise for that. Secondly, i don't really know what quantum computing is, I'm basically guessing... To give you an idea of what my understanding of certain ideas might be, I start my...

Homework Statement L is the langrangian \dot{q} is the velocity with time derivativeHomework Equations \frac{\partial L}{\partial \dot{q}} = -M \frac{1}{2} \frac{1}{\sqrt{1- \dot{q} \cdot \dot{q}}} \frac{\partial}{\partial q_i} (-\dot{q} \cdot \dot{q}) The Attempt at a Solution A few...

Homework Statement A vector is given by R = 2.00 i + 1.70 j + 2.81 k. (a) Find the magnitudes of the x, y, and z components. x = 2 y = 1.70 z = 2.81 (b) Find the magnitude of R. 3.85 (c) Find the angle between R and the x axis. ...

Hey guys, I´m really interested in Quantum Computers and i´d love to work on them. I´ll have to decide my carreer soon, and i wanted to know what should i study, either Physics or Computer Science? I know that eventually I´ll have to study both...but what makes more sense to you guys?. Thanks!

Hello, I'm wondering if there are any tricks to quickly determine the parity of the weight of a binary number, i.e., whether it's even or odd. I'm not interested at all in the actual weight of the number, but in the parity of it. I know that if say x = a XOR b, then x has odd weight iff...

This question came up in conversation the other day and I was wondering if anyone could quantify this. How far back in time must I go before I find a desktop computer that is only as powerful as my Nexus S smartphone? Would that be a Pentium III, for example? I understand that the answer...

I've posted a bunch of analysis questions as of late. I'm going to change things up a little bit and ask something that involves manifold theory. Here's this week's problem: ----- Problem: (i) Let $\omega$ be a 1-form. Use the structure equations \[\begin{aligned}d\theta^1 &=...

Hello, I'm trying to calculate Fisher information (and eventually the Cramer-Rao lower bound) for this particular pdf with Mathematica: \text{pte}[t,\Theta ] = \frac{P_{\text{ec}}}{\tau _d-\tau _r}\left[e^{\frac{-(t-\Theta )}{\tau _d}}-e^{\frac{-(t-\Theta )}{\tau _r}}\right]...

Hi, so this is my first time on this forum and I've just gotten very frustrated with trying to understand this one problem. I got part A by using divergence theorem but I don't know how go about computing part B. Suppose F⃗ (x,y,z)=⟨x,y,5z⟩. Let W be the solid bounded by the paraboloid...

Homework Statement Homework Equations The Attempt at a Solution I can't get the answer above. Is u -4 over 15? if so, the dot product of u and x should be -20 + 105. I'm clearly on the wrong track.

I was flipping through Kitaev's quantum computing book today and noticed something really strange. I thought it might be fun to post it here and figure out what's going on. See...

We occasionally get questions related to codes and computational methods. There have been considerable advances in computational methods and computational systems in the field of nuclear energy and nuclear engineering. This thread serves to address previous developments and follow current...

I am reading Thurston's book on the Geometry and Topology of 3-manifolds, and he describes the metric in the Poincare disk model of hyperbolic space as follows: ... the following formula for the hyperbolic metric ds^2 as a function of the Euclidean metric x^2: ds^2 = \frac{4}{(1-r^2)^2} dx^2...

\int_0^\infty e^{-x^2}dx \int_0^\infty e^{-y^2}dy = \int_0^\infty \int_0^\infty e^{-(x^2+y^2)} dxdy Under what conditions we could do the same for other functions? I don't get how Poisson (or Euler, or Gauss, whoever that did this for the first time) realized that this is true. It looks...

Hello! I am new here and I will try my best to clarify my questions and not violate the forum rules. Just for the record, I am not particularly good at understanding equation-saturated explanations because I am not an expert. However, I did a lot of searching and I still don't understand...

I've been trying to calculate the Riemann Curvature Tensor for a certain manifold in 3-dimensional Euclidean Space using Christoffel Symbols of the second kind, and so far everything has gone well however... It is extremely tedious and takes a very long time; there is also a high probability...

Homework Statement Show that ##\iint_{S}(x^2 + y^2)d\sigma = \frac{9\pi}{4}## where ##S = \{(x,y,z): x > 0, y > 0, 3 > z > 0, z^2 = 3(x^2 + y^2)\}## Homework Equations ##\iint_{S}f(x,y,z)d\sigma = \iint_{R}f(r(x,y))\sqrt{[r_x(x,y)]^2 + [r_y(x,y)]^2 + 1}## where ##r : R → ℝ^3, R \in ℝ^2##...

Hello, anyone knows where y can find a program to compute the integral ∫ ( from -1 to 1) f(x)/ √(1-x^2) using the Gauss-Chebyshev quadrature, on matlab? Thanks!

I'm having a really hard time working with non-standard expressions for the curvature. This deals with two expressions for the curvature, one for a 2D plane curve, and the other for an axi-symmetric surface in 3D. The plane curve Suppose we have a plane curve given by x = h(y) for both x...

I want to know if a quantum computing model exists where you can prepare two different states on n qubits and interfere (i.e. add) them together. For example, for two qubits, consider the states (|00> + |01>)/√2 and -(|00> + |10>)/√2 (both pretty easy to prepare in most quantum computing...

I have a pretty urgent question concerning the calculation of the class group, so any help will be very much appreciated:) I'd like to illustrate my question with an example: Calculate the ideal class group of Q(√-17), giving a representative ideal for each ideal class and a description of the...

I have a differential that depends only on \cos{\theta} \frac{\operatorname{d}\sigma}{\operatorname{d} \Omega} = f(\cos{\theta}) I am numerically solving this differential equation for \sigma, which physically is a cross section, for 0 \leq \theta \leq \pi. The differential contains a...

Does anyone know an algorithm for computing kronecker products of two matrices? It's probably not that hard, but I feel like my head is about to explode ATM, so if you can help me out that'd be cool. I want to implement this in fortran... I'll give you an example; Say I want compute the...

Homework Statement Compute the Fourier transform of f(x)=exp(-b|x|), b>0 Homework Equations F(k)=1/2pi(integral[inf,-inf]f(x)exp(ikx)dx) The Attempt at a Solution F(k)=1/2pi(integral[inf,-inf]exp(ikx-b|x|) How do I solve this? I've tried to solve it but can't get to a solution...

I'm not really sure what I want to do after A level yet but I've sort of narrowed it down to Physics, EE, ChE, or Materials Sci. (OK its not that narrowed down) I've worked out that if I take: Maths Further Math Physics Chemistry That I should be covered for any of those 4 courses...

What are you guy's thoughts on constructing a quantum computer from attosecond double-slit phenomena?

I just was wondering if anyone here has pursued a degree in scientific computing / high performance computing / computational simulation and modeling, type of degree. For example Georgia Tech's Computational Science and Engineering degree or Computational and Mathematical Engineering degree, or...

Say I can get some used MB with CPU and RAM on it at a very low price, and a DMA 33 hard drive, home made powersource, how am I going to get all thoese MB connected? Using PCI slots? AGP slots? Or para. Ports? USB ports? Does Beowulf even support HD farm? That would be mind-blowing advance...

Here is what I've done so far How do I draw the Phase portrait for this system? Have I done everything correct so far? Thanks