Computation Definition and 250 Threads

I am reading chapter three of Huang's Statistical Mechanics and I have a problem with equation (3.22). Having discussed the derivation of the classical cross section for a scattering process, Huang moves on to the quantum version of it. He states that in quantum mechanics the fundamental...

hi simple computation A = 60x60x100 B = 60x60x30 I want to find A*B, by this I mean, I want a 100x30 output matrix where element (k,m) represents the sum of A(i,j,k)*B(i,j,m) over all i,j My brain is simply not working and I'm confusing myself, does anyone have a short line of code to...

As an exercise, I'm trying to compute the class number of K = \mathbb{Q}(\sqrt{30}). By the Minkowski bound, I just need to consider the prime ideals which divide 2,3,5. I've found that (2) = \mathfrak{p}^2_2 (3) = \mathfrak{p}^2_3 (5) = \mathfrak{p}^2_5 where...

Hi, I wrote a piece of MATLAB code to compute a double integral of the form: \int_{a}^{b}\int_{c}^{d}f(x,y)dxdy I went about it using the trapezium rule, so what I did was apply the rule to the x variable first to obtain: \int_{a}^{b}\int_{c}^{d}f(x,y)dxdy\approx\frac{\delta...

Let $f(x)=-x$ for $-l\le x\le l$ and $f(l)=l.$ a) Study the pointwise convergence of the Fourier series for $f.$ b) Compute the series $\displaystyle\sum_{n=0}^\infty \frac{(-1)^n}{(2n+1)}.$ c) Does the Fourier series of $f$ converge uniformly on $\mathbb R$ ? ------------- First I need to...

Homework Statement The problem is in the provided link (it is questions 2.2) http://www.docstoc.com/docs/3817109/Chapter-Problems-A-car-travels-up-a-hill-at-a Homework Equations The Attempt at a Solution I understand the duration of time it takes to go up the hill is a larger time...

A simple computational question, that I saw in a journal article and have been having trouble getting. Define the variable V (implicitly) by: V=b + \int^{rV}_{0} rV dF(s) + \int^{\infty}_{rV} s dF(s), where r is a constant and F has support on [0,∞). Question: Show that...

Okay, this is not a homework problem, and I think if I really played with it long enough I could work something out. But really, I just want an answer, so I'm hoping someone on here who really loves solving problems like this can just knock it out. It would be much appreciated. I'm wondering...

Dear All, I started to look around for a reliable definition of the differences between Calculation, Computation and Simulation, but I'm not satisfied with what I've found. In your view, what are the correct usages of these terms? When something becomes more than a computation or calculation...

I'm a bit confused about entanglement with regards to quantum computing. I'm not an expert by any means, but I've been reading around about quantum computing and was confused about something. I've read that, you can't directly observe a qubit, because if you do the wave function will collapse...

I'm looking at some code from a book that details uses the heliocentric position and velocity to compute an orbit of a meteor. See attached pages. At the top of the section at mid-page, page 37, he gives a source, Herget, 1953, Solar Coordinates 1800-2000. The book was written in the...

hi when i run a heavy computation on mathematica in the same time even if i want to calculate 2+2 , mathematica does not calculate it until calculating of heavy computation finishes. why? another problem is that when i do a heavy computation and obtain results , after closing mathematica...

Homework Statement To plot the bandstructure of a free electron in silicon using python. Homework Equations We have been told that to do this we must use the 15 lowest magnitude reciprocal lattice vectors (so 2pi/A (0,0,0), (1,1,1), (-1,1,1) etc...). We are then told to setup a matrix with...

Bonjour, I need to numerically compute the net electrical resistance of a given geometry. I know the shape of my object, it is relatively simple. It's close to this: http://2.imimg.com/data2/QX/UC/IMFCP-3019296/i-shape-big-1-250x250.jpg Actually my shape is even simpler because it's a...

I'm in 3rd year math, and out of the 11 courses I'm taking this year, 2 are computationally based (Calc III and Calc IV). I just finished my CalcIII midterm, I know i did fine, definitely a 90 or higher, but I just want to discuss how much I hate computation, and if anyone agrees with me. I'm...

Hi all, can you help me to compute these integrals? \int \frac{x \sqrt{a x+b+x^2}}{d^2+x^2} \, dx \int \frac{x}{\left(d^2+x^2\right) \sqrt{a x+b+x^2}} \, dx a,b and d are real and positive. I tried with Mathematica, but the results involve logarithmic functions with complex...

(1) Let s be a complex number like s = a + b i, then we define \zeta(s) = \sum_{n=1}^{\infty} \frac{1}{n^s} Our aim: to compute ζ(\frac{1}{2}+14.1347 i) with the help of the programming language Aribas (2) Web Links Aribas...

Hams and Raedt gave a quantum computational algorithm to calculate the density of states of a spin system. Starting with an initial random state, they obtain the time evolution of the state. Later they take the inner product of the evolved state with the initial state. How does the inner...

I want to basically have a dedicated machine for running scientific computation programs and be able to access it remotely anywhere using a laptop/netbook. That means I don’t care much about GUIs. I’m used to using Unix and am perfectly fine with doing everything through a command window. At the...

In this field, computer algorithms may produce false continued fraction expansions because of the limited accuracy in the floating point arithmetic used. Who knows more?

Good night, I want to study by myself Theory of Computation and its three main areas: Computational Complexity, Automata Theory and Computability. I find Algorithms and Algorithm Analysis to be specially interesting (although I don't know exactly where this topic fits). I am starting to...

I've written a Python program to simulate a meteor falling into the Earth's atmosphere. It's fairly straightforward. I give it the lat/long of two observing stations, and the lat/lng where the meteor begins along with an angle from north for the direction. An initial height above the beginning...

What is wrong with this computation ? (1) Mass of Earth's atmosphere is 5 x 10^18 Kg. (2) The heat capacity of dry air, Cp, is 1 KJ/Kg-K (3) BP states that the amount of fossil fuels burned worldwide in year 2008 was 11,295 million tons. Round that to 11 billion tons. (This may be...

Homework Statement Hi there, I'm very new here and I was hoping someone would be able to help me out a bit! I have a few questions but right now I'm going to start with this problem. Elements A and B form ideal solutions in both liquid and solid phases. Compute the A-B phase diagram using...

Dear all, I'm new in the DFT word and I wish to calculate as a practice the \alpha/\beta quartz phase transition as function of temperature. For each phases I imaged preforming CPMD simulation for a given temperature range and then calculate the phonon DOS. From the later I should be able to...

Homework Statement Give state diagrams of DFAs recognizing the following languages. In all parts the alphabet is {0,1}. {w | w has length at least 3 and its third symbol is a 0} Homework Equations If the final state only has one circle it is rejected, if two, accepted. The Attempt at a...

Homework Statement Differential equations are important in physics.Consider Solving the differential equation dy/dx = Σ(from i to N) (ai) (x^i) Using Euler ,Midpoint ,4th order Runge -Kutta methods.For each of these methods what is the largest value of N that would lead to an exact solution ...

Homework Statement Homework Equations Fundamental theorem of calculus. The Attempt at a Solution For the first problem, I'm completely lost. I've only worked with slant asymptotes for polynomials so finding the domain, range and intercepts is as far as I've gotten. I'm not too...

Homework Statement x(t) = t*exp(a)*exp(-a*t)*u(t-1) - exp(a)*exp(-a*t)*u(t-1) I need to find X(jw)... Homework Equations how to apply properties of Fourier transform to get an answer? Because i know that the only effective method for this.. The Attempt at a Solution For...

Hello, I am trying to develop a formula to calculate the force of water sloshing against the inside of a cylinder. While there has been a lot of development of baffles and structures designed to minimize the effect of sloshing liquids in tanks, we are doing some studies of liquids in small...

Hello, I am a sixth form student studying physics and I am planning on doing a project on electronic analog computation and I am stuck as to where I should begin to learn how such a system solves problems (without delving too much into too many details). I have limited knowledge on electronics...

Hi, I want to calculate the angle of 6 point on a sphere. Five points are aranged in a cross, one point in the middle, and one on each side. All outer points are delta degrees distance from the center point. Define the axis going through the center point and the center of the sphere as X. The...

Hi all, This question has been intriguing me for a long time and now that I discovered this forum I thought it is a good place to ask. Take a typical CPU. To operate it draws energy from the power supply, does some computation and emits heat. Since state of energy can only be transformed...

Homework Statement Compute Ext(R,Z) where R is the real numbers and Z is the integers Homework Equations The Attempt at a Solution This is part of a problem is given in Hilton-Stammbach page 109; the previous parts of the problem asks to compute Ext(Q,Z) and Hom(Q,Q/Z); I have...

Hello, I was wondering, if there is some good and easy to use computer programm, that, given a set of polynomials, tells me if they generate a radical ideal. Preferably as a Mathematica package.

The base of each solid below is the region in the xy-plane bounded by the x-axis, the graph of \[y=\sqrt{x}\] and the line x = 3. Find the volume of each solid. a) Each cross section is perpendicular to the y-axis is a square with one side in the xy-plane. b) Each cross section is...

Hi, though I am trying to compute the subbands structure of a rectangular nanowire using an 8X8 KP Hamiltonian, I am not getting the right results. As it is only a month or so that I started to study the topic I was wondering if somebody may give me an advice. Currently I am writing the...

Hey folks, I'm rather stuck. I have a complete mental blank on this question. Having the force couple first has confused me I think Homework Statement Compute the forece supported by the pin at C for the frame subjected to the 400-N.m couple Homework Equations...

The generating functional Z[J] depends on \phi_{cl} trough its dependence on J. At the lowest order in perturbation theory the relation between J(x) and \phi_{cl} is just the classical field equation: \left(\frac{\delta L}{\delta \phi}\right)_{\phi=\phi_{cl}} + J(x) = 0 The question is...

Ok it says I am to computer using a series accurate to within 0.001. I'm really not sure where to start. Do I integrate this first by parts? Or am I thinking about this too much? Could someone point me in the right direction please! Help would be much appreciated!

Hello, I have a state of two registers (A and B) which is in the following form respect to the computational basis: |v> = \frac{1}{N}\sum_{k=0}^{N-1} |k>_A |f(k)>_B I don't know how to prepare this state, it is externally given. I would like to extract the value of f(\hat{x}) for some...

Hello, I am reading the book on algebraic topology by Fulton and the geometric intusion that is supposed to be given for homological group is the number of connected components. I wanted to understand an example. For a circle ( S1) which has got 2 points say A at ( 1, 0) and another...

hello,i had posted in this forum a question about linar algebra and quantum mechanics because i am studying quantum computation and information, i have the following book:"quantum computation and quantum information" by Michael A.Nielsen and Isaac L.Chuang. and i think it covers most topics of...

Homework Statement Say, i have a setup as shown on the photo below http://www.flickr.com/photos/47719498@N07/4375079183/ * setup also seen as attachment how can i be able to compute for the dielectric constant provided it is not parallel plate and considering two different area is...

I've the following problem. I have two four-vectors p and q where p is timelike ( p^{2} > 0 ) and q is spacelike( q^{2} < 0 ). Now I should consider the quantity - \dfrac{2 (pq)^{2} + p^{2} q^{2}}{q^{2}} and compute the limit q \to 0 . But I don't know how to perform the limit...

Hello, everyone. I've been reading this site off and on for a few weeks, and I'd like to ask you a few questions, if you don't mind. I'm a 30 year old software developer with a BS in computer science (and a mostly completed MS that I really regret not finishing). I generally enjoy my work...

Hello, I am quite new here, as my number of posts might indicate. Thus I am not really sure whether or not this question should be posted here or somewhere else. It is not a homework, but neither is it a question that could not be a homework. However, here we go. I have, during a course in...

Homework Statement A surface has the area vector A = 2i + 3j. What is the flux of a uniform electric field through it if the field is E = 4i? 2. Homework Equations Integral calculus, vectors The Attempt at a Solution I don't understand why one could do this. The integral is of E and...

Homework Statement Which of the following can be computed? 1. A dot B dot C 2. A dot ( B dot C ) 3. A dot ( B + C ) 4. 3 dot A Homework Equations The Attempt at a Solution I believe that 2 and 3 are the only two that can be computed. Can anyone confirm this? Thanks.

Hi, I'm having problem with understanding tensors and the Einsteins summation convention, so I decided to start doing explicit calculations, and I'm doing it in the wrong way. Hope someone could help me to clarify the concepts. In flat spacetime we have \eta with the signature (-+++). Under...