Local Definition and 521 Threads

Dear PF could you advise me Whether I understand properly or not: In an arbitrary space-time (with an arbitrary curvature) in any sufficiently little region we can go to Local Inertial Frame of Reference - sit into the free falling lift. Being there our experiments are the same as we have...

I have been walking around with the notion that "quantum entanglement implies a sort causal relationship due to the states having a shared history". I am now not so sure that this is correct. When I talk about entanglement, I use the argument that the preparation of the entangled state...

Hi, I would like to know what local density of states (LDOS) is and what differences it has with projected density of states? Also, when we choose a smaller isolevel we have a denser local densities of states, why? Regrds,

In which direction lies the center of the local group?

In Hatcher's book, http://en.wikipedia.org/wiki/Talk:Coherent_topology, see the very end of page 135 and the beginning of page136 for the definition of the local degree of a map S^n-->S^n. I don't get how the local degree degf|x_i could be anything else than ±degf: In the diagram of page 136...

I've just been reading about how complex functions can be defined on the extended complex plane. They start with rational functions as examples, and defining them at oo so they're continuous at oo in a sense. Eg, 1/z would be defined to be 0 at z = oo. I understand that given a holomorphic...

If there is Dark Energy expansion of space throughout this Universe why is it not noticed, at least to some extent, within our Solar system? Can it only be noticed on a Grand Scale?

F(x)=x^m * (1-x)^n where m and n is greater or equal to 2? find the x coordinates of local extrema? would my answer be with respect to m and n? or do i plug in a number for these variables

Can someone please explain to me this internal symmetry... Also please do take mind that i don't have strong mathematical knowledge, YET... but can u state out the conceptual, non-mathematical, principles in local U(1) Guage -Invariance and how it reasons for virtual phton exchange which...

How i can see the right lorentz invariance in lqg?

A while ago I was having an interesting thread here about the possibility of local MWT, MWT as a local explanation of the entanglement experiments. In re-reading this discussion I was wondering whether the proposal of MWT as a local theory means: a) Hidden variables are necessary but MWT...

If f(x,y)= xy+(1/x)+(1/y) I find that fx= y-(1/x2)=0 and fy=x-(1/y2)=0. Solving for coordinates x and y by substituting the equations, I find that y=0 or 1. However, if i try to solve for x-coordinates with y=0, I get an infinity. So does that mean I ignore the possibility of y=0? Another...

[SOLVED] Determining Local Extrema with Lagrange Homework Statement Find local extram of f(x,y,z) = 8x+4y-z with constraint g(x,y,z) = x^2 + y^2 + z^2 = 9 Homework Equations \nabla f(x,y,z) = \lambda g(x,y,z) The Attempt at a Solution So I did the partial derivatives for F and...

please help me out! military service? or ph.d in local univ? hello~ i just started my Masters in Physics. and i have a problem. AS A VICTIM OF Kim Jong-il(i live in S.Korea lol), i got to do my military service. And I can think of only 2 options for now 1. keep studying here and finish my...

I am trying to debug a SUPG FEM code for flow problems (based on Brooks Hughes 1982) and have a question about the Lumped Mass Matrix. My understanding of the Lumped Mass Matrix is that for any given element the mass of that element is simply distributed evenly over the number of nodes. In...

hi, g.r speeks of the ability to constract local lorentz frame. how can an observer construct such a frame if spacetime is curved? what are his rods and clocks? it seems that if one tried to construct a "hive" of coords using a ruler, then it will not cross as expected... he might even...

Is it possible to describe spontaneous breaking of the local gauge symmetry in the standard Hamiltonian formalism, without any manual redefinition of the gauge field( A(r) -> A(r)+▽Λ(r) )? Detailed description of my question is given below.(Quite lengthy.. sorry.) 1. By the 'standard...

If you are under 17 you will not be allowed into the mall after 5 PM on Fri. and Sat. nights unless you are accompanied by an adult. http://cbs3.com/local/Delaware.Mall.Teen.2.769257.html I'm so glad they instituted this rule. The stupid kids that hung out there would just fight all of the...

Why isn't our Local Group's dipole for Microwave Background Radiation pointed towards the center of mass for our Local Supercluster? Clusters are suppose to be just infalling towards gravitational well of it's supercluster. http://en.wikipedia.org/wiki/Cosmic_microwave_background" See...

Why is local gauge invariance needed in qft? I read that is allows interactions whereas global gauge invariance does not but was given no reason.

Homework Statement y1'= −4*y1+y2+y1*y2 y2'= −2*y1−y2+y1*y1 Determine the three critical points of the system and their type of local phase portrait (stable node, unstable, saddle point, spiral, center, no node) Hence I need to get three critical points (x1,y1), (x2,y2) & (x3,y3) and their...

Homework Statement This theorem is from Shiryaev. Can someone PLEASE explain how they are using the little o notation here. It makes no sense to me how they say that a FIXED real number is little o of something. I thought f(n) = o(g(n)) mean that for ever c>0 there exists an n_o such that when...

Can a space be path-connected and not locally path-connected? (To be clear, "locally path-connected" just means that there is a basis of path-connected of sets.) My general intuition says no, but my intuition seems to usually be wrong...and this would explain why Hatcher keeps referring to...

The Phillies game isn't on local TV today, it's only on MLB tv. That's just not right. Americans should not have to live this way.

Homework Statement a) Graph y = -x^5 +5x -6. Include coordinates of local max, min, and points of inflection. Indicate the behavior as x-> -infinity, x -> infinity. b) Find in slope-intercept form the equation of the tangent line to the curve at x = 2. Homework Equations The Attempt at a...

When is the next "13.00 Local Sidereal Time" for a UK observer? Anyone with software or equations to work that out?

I wonder if there are coordinate systems that gobally curve and twist and turn and curl, that do NOT admit local orthonormal basis. I know that the Gram-Schmidt procedure converts ANY set of linear independent vectors into an orthnormal set that can be used as local basis vectors. And I assume...

http://www.geocities.com/asdfasdf23135/advcal29.JPG I am wondering whether the above statement is true. "A necessary condition for the constrained optimization problem to have a GLOBAL min or max is that..." Should the word local replace global? I am confused about the method of...

for the equation... y = x^3 - 2x^2 -5x +2 is its local minima at (2.120,-8.061) Thanks

I am not a physics major but have always been perplexed by the apparent paradox of two issues: 1. If we use the Hubble telescope to view items 10B+ years in the past yet the universe is expanding, what was the actual physical location of these bodies at the time the light was produced...

Local Gauge Symmetry ?? Trying to understand local gauge symmetry ================================ I have an undergraduate degree in physics, so I know basic quantum mechanics, but that's all. Still, I'm trying to understannd the concept of local gauge symmetry. I would appreciate if...

[SOLVED] Local Max & Min problem I'm having a real tough time finishing this problem. I have to find the local maxima and minima points for g(x). g(x) = 1 + 4x - 10x^2 + x^4 (dy/dx) = 4 - 20x + 4x^3 I've been trying to factor it to get the max and min points, but I find it...

First: the Earth rotates with angular frequency w, with the rotation vector in the z direction. it is then useful to define a local coordinate system i', j', k' fixed on the Earth's surface (i.e. a cartesian coordinate system for us in our point of view on the surface of the earth) then to...

1. Find the local max and min of x/(1+x^2) The Attempt at a Solution Take the derivative of x/(1+x^2) and set it equal to zero. f'(x)= (1-x^2)/(1+x^2)^2 = 0 This is where I am stuck. My first guess was to factor the top, resulting in (1-x)(1+x)/(1+x^2)^2 = 0, and then cancel the 1+x...

I'm a writer working on my first novel. The genre is science fiction and I'm trying to keep the science part of it as close to the realm of possibility as I can. The setting is in a smaller system about 10 to 50 light years of our system. Can someone name a star and its location that is of...

1) f(x,y,z)=x3-3x-y3+9y+z2 Find and classify all critical points. I am confused about the following: The Hessian matrix is diagonal with diagonal entries 6x, -6y, 2. Now, the diagonal entries of a diagonal matrix are the eigenvalues of the matrix. (this has to be true, it is already...

I have a function that looks like this: http://rpi.edu/~doriad/view1.jpg The function is non analytic, so I have to use something like the steepest descent method with numerical gradients to find the minimum. However, if my starting point is on the left of the tall peak, the min I find is on...

In chapter 4 of Bailin & Love, Supersymmetric gauge field theory and string theory, the authors state that supersymmetry is considered a global symmetry, and we can separately consider it to be a local symmetry. Further, since the supersymmetry algebra contains P^\mu, the generator of...

Say we have a BELL state |B00> = cos(a) |00>+ sin(a) |11> then for a (just one) pair of entangled particles, we keep one on location q, the other one in location w; the one in q forms a system Q, the one in w forms W. ( 'x' in a function like |v> x |w> indicates a tensor product)...

I thought local extremum did not exist at the endpoints of a closed bounded interval, however my textbook claims this. Wikipedia: "A continuous (real-valued) function on a compact set always takes maximum and minimum values on that set. An important example is a function whose domain is a...

Homework Statement Find the stationary points and local extreme values of f(x,y) = xy^2e^-(\frac{x^2 + y^2)}{2} Homework Equations You need to find the gradient for the function and then set it equal to 0. So then df/dy equals df/dx and you can solve for a solution set.The Attempt at a...

I have read a number of threads on acceleration and special relativity, but can't find what I'm looking for. I would like to know, in the context of special relativity, how to compute the acceleration "felt" by an observer, and how to transform this acceleration into different inertial frames...

Homework Statement The velocity of the water in the pipe is given by v1=.5t m/s and v2=1tm/s, where t is in seconds. Determine the local acceleration at points 1 and 2. Is the average convective acceleration between these two points negative, zero, or positive? Homework Equations A...

What kinds of local stores sell pulleys? I can't buy online because of time limit. Are the like physics stores around cities? Or do like Arts & Crafts stores sell them? 91739

arXiv:0712.0370 [ps, pdf, other] Title: Local Void vs Dark Energy: Confrontation with WMAP and Type Ia Supernovae Authors: Stephon Alexander, Tirthabir Biswas, Alessio Notari, Deepak Vaid Comments: 26 pages, 11 figures Subjects: Astrophysics (astro-ph) It is now a known fact that if we...

[Related concepts: Inverse mapping theorem, transformations and coordinate systems] 1) For each of the following transformations (u,v) = f(x,y), (i) compute det Df, (ii) find formulas for the local inverses of f when they exist. a) u=x^2, v=y/x b) u=(e^x) cos y, v=(e^x) sin y I got...

Homework Statement Classify the local extrema of f(x) = x/2 + cos(x), 0 <= x <= 2pi. Give the exact values of the critical numbers and extrema. Find the absolute (or global) maximum and minimum values of the function. The Attempt at a Solution So i need to find the critical numbers...

What is the estimated value of the local star formation rate (SFR) and how accurately do we know this number?

Since there is a significantly-above atomic limit to the allowed sharpness of an (approximately zero-dimensional) needle point due to its local electric field, would there be a similar limit to the keenness of an (approximately one-dimensional) razor edge?

Homework Statement Sketch a graph of a function f that is continuous on [1,5] and has no local maximum and minimum, but 2 and 4 are critical numbers. Homework Equations The Attempt at a Solution Knowing 2 and 4 are critical numbers, I formed the base function x^{}2-6x+8. Not sure...