Local Definition and 491 Threads

This thread is an offshoot of https://www.physicsforums.com/showthread.php?t=403210 -- Joy Christian's disproof of Bell. This thread is a response to: THE SAKURAI LINK (above) SHOULD BE STUDIED AND UNDERSTOOD. This thread also has its basis in the following [somewhat edited] exchange: So the...

I feel I may have improperly posted this thread https://www.physicsforums.com/showthread.php?t=469331" but am just not as knowledgeable in my matrix math as I need to be. One (me) would think that somehow you should be able to get a rotation matrix from these two systems. Homework Statement So...

The wikipedia article on connection forms refers to a local frame. What is the relationship between local frames and coordinate bases? Are they the same thing? Is one a subset of the other? The connection form article uses general notation e_\alpha for the basis elements instead of the...

Homework Statement minimiza f(x) = x_1 subject to (x-1)^2+y^2=1 (x+1)^2+y^2=1 Graph the feasible set, Are there any local minimizers and global minimizers? Homework Equations I have graphed the feasible set...

The concept of “fields” told us that our physics is local, while the concept of "entanglement" seems to say that there is something nonlocal So I wonder whether our physics laws are local?

First let me apologize for asking these questions. So much has been devoted to discussing the expansion of space both on the internet in general and this forum that the answers to my question are probably out there, but there is a lot to wade through. A lot. I found this forum and thought...

Hi, I have a question about gravity. I think most of you know that we can obtain Einstein gravity by gauging the Poincaré algebra and imposing constraints. The Poincaré algebra consists of {P,M}. P describes translations, and M describes Lorentz rotations. Gauging M gives us the so-called...

Homework Statement For some reason, the uniform topology always causes me problems. So, let's work this through. Let Rω be given the uniform topology, i.e. the topology induced by the uniform metric, which is defined with d(x, y) = sup{min{|xi - yi|, 1}, i is in ω}. Given some n, let...

[(there is an option that there is no Local minimum or Maximum point in this Function) BUT i need to show the way. thanks.

Homework Statement Find a cubic function g(x)=ax^3 +bx^2 +cx +d that has a local maximum value of 2 at -9, and a local minimum value of -7 at 8. Homework Equations The Attempt at a Solution I thought i would find the derivative and set it equal to zero, but i do not know what to...

Homework Statement This one has been bothering me for a while. One needs to show that [0, 1]ω is not compact in the uniform topology. The Attempt at a Solution As a reminder, the uniform topology on Rω is induced by the uniform metric, which is defined with d(x, y) = sup{min{|xi -...

Without adding new Fields, how do I use local variables from another method in the same class? I know I could simply add these variables to the list of Fields and get to them that way but our instructor specifically told us NOT to do this. I am stumped. Heres the realavent code, in bold are the...

Einstein's equivalence principle states that free-falling observers are in local inertial frame, so one can construct a local Minkowski frame everywhere. So my question is whether the logic can be inversed, does every local Minkowski space represent free-falling? because in vierbein...

Homework Statement Find the local maximum and minimum values and saddle point(s) of the function. f(x,y) = 1 + 2xy - x^2 - y^2 Homework Equations The Second Derivative Test: let D = D(a,b) = fxx(a,b)*fyy(a,b) - [fxy(a,b)]^2 if D > 0 and fxx(a,b) > 0, then f(a,b) is a local minimum...

Can any continuous coordinate transformation on a differential manifold be viewed as a poincare transformation locally in every tangent space of this manifold? Thx!

Homework Statement Let X be locally path connected. Show that every connected open set in X is path connected. The Attempt at a Solution Let U be a connected open subset of X. Since, X is path connected, for any x in X and any neighborhood N of X, there exists a path connected...

Hello all I am trying to teach myself general relativity and am working through the text 'a first course in general relativity' by Bernard F Schutz. So far I have made slow but consistent progress but I am perplexed by his derivation of the ‘local flatness’ result. This says that for any point...

I live in ottawa and apparently University of Ottawa and Carleton University's admittance rates are both 75% for specialization in Math. Is is like that for most universities? This percentage holds true to physics as well. Engineers are more in the 80s.

Homework Statement My first lab report in physics requires me to calculate the value of local gravity. I did this using latitude and longitude. I must also state the uncertainty of my local gravity value. I have no clue how to do this. What am I basing my uncertainty on, and is there an...

Blandford & Thorne, Applications of Classical Physics: Taylor & Wheeler, Spacetime Physics: These definitions seem to be based on the notion of a "physical" or "practical" infinitesimal: a quantity too small to be detected. But how can we measure the accuracy of an imaginary detector...

I've been exploring an idea for reconciling the possibility of local realism with the various experimental proofs of violations of Bell's Inequalities. Since it seems like an idea that must have been explored and considered elsewhere, I am looking for relevant papers which have considered the...

Ok, so say I have a system at a global temperature, I add an energy source (laser in this case) and it heats the system in a localized area. This leads to a maximum temperature peak in the system. Then you can get out a change in temperature from this maximum to the global. OK, now my...

The action for a fermion in curved spacetime is S = -\int d^4 x \sqrt{- \det(\eta^{ab} e_{a\mu}e_{b\nu})} \left[ i\overline{\psi} e^\mu_a \gamma^a D_\mu \psi + i m \overline{\psi}\psi \right] where g_{\mu\nu} = \eta^{ab} e_{a\mu} e_{b\nu} and the derivative operator acting on fermions is...

Local "news"? Sometimes I think all local news is for is telling us what the weather will be like and what's going on at elementary schools. So far I swear they went on for 5 minutes about how the air conditioning went off at an elementary school for 2 whole days! WHO CARES?!??! I'm just...

This is related to the thread on the meaning of diffeomorphism invariance but is adressing a distinct point (at least I think so, but I may be proven wrong). As Rovelli discusses in his book, the action of the Standard Model coupled to gravity has three types of invariance: under the gauge...

I don't know if this is the right place to post this, but my question is: if i have an Hamiltonian defined on the whole phase space and a function f which is also defined on the whole phase space and doesn't depend explicitly on time, i know that if its poisson bracket with the Hamiltonian...

What about the nonlinear forms of it? Or is it guaranteed to reach a global minimum?

Hello, just got done taking a test and one problem kinda confused me. Homework Statement f(x,y) = e^x cos y find local min/max and saddle points Homework Equations fx = e^x cos y fy = -e^x sin y The Attempt at a Solution I answered that there were no critical points for...

Does a constant function have a local maximum?

Homework Statement I am wondering how did the local graviational field (free fall acceleration) g = 9.81m/s^2 is calculated? Homework Equations The Attempt at a Solution

Let R be a ring . Suppose that e and f=1-e are two idempotent elements of R and we have R=eRe \oplus fRf (direct sum ) and R doesn't have any non-trivial nilpotent element . Set R_1=eRe and R_2=fRf . If R_1=\{0,e\} and R_2 is a local ring , then prove that R_2 is a division ring . (note that e...

Can anyone tell me about how to use the local density approximation in density functional theory analytically if it possible?

Suppose one had a solid sphere just slightly larger than its Schwarzschild radius. What would the curvature of the surface look like to a local observer? Would it curve downwards, or appear flat, or curve upwards? If my brain was working a bit better today, I'd calculate it myself from the...

Hey, To promote understanding of science I want to write a short article every week for my local newspaper. Four articles will be sent to them as a taster to get their agreement; a snippet, a column and two full length articles. Four subjects that are easily accessible and also...

Take the following setup: A series of pulses of radio signal is relayed around the world, along the equator. There is no "gap", it is a continuous loop along numerous relay stations build along the equator. The total number of pulses is fixed at 648,000 - I'll explain in a minute why that...

1. Use the following equations to fill in the missing numbers. The correct addition and subtraction signs have already been entered. PROBLEM ONE: f(x) = ax4 + bx3 - cx2 - dx - e Find values of a,b,c,d, and e so that the function has inflection points at ((v3)/3, -7.5752) and (-(v3)/3...

Homework Statement h is the timestep Y' = F(Y) Mk,1 = F(Yk) Mk,2 = F(Yk + 0.5*Mk,1) Mk,3 = F(Yk + h*Mk,2) Mk,4 = F(Yk + h*Mk,3) Yk+1 = Yk + (h/6)*(Mk,1 + 4Mk,2 + Mk,4) Show that the local error is of fourth order The Attempt at a Solution I have written down the...

So much hay is made out of the fact that quantum theory—and its associated experiments—violates the principle of local causality, as canonically developed by the classical (Newtonian) and relativistic (Einsteinian) models. But no one ever really asks about what these models are 'truly' saying...

The question asks for local minimum of x^4-9x^3+9x^2+5x-4. The answer was x=-0.21 and 5.96. I thought 5.96 is the absolute minimum, since it gives the loweset y value on the open interval. Where am I wrong. Thanks.

Homework Statement Hey, so i need some help trying to find the local max and min points for y = sinxcox3x Homework Equations The Attempt at a Solution I know i need to find the first and 2nd derivative but i do not know if i am doing it right. I also do not know what to do after wards. my...

[b]1. An astronomer at the Dominion Astrophysical Observatory (DAO), located at latitude 48° 31' N in Saanich, near Victoria, B.C., is studying the K2 III star N'3148°α Arietis. The equatorial coordinates of α Arietis are right ascension=2h 07 m 30s and declination of 23°29' If the...

For any constant c, define the function f-subscript c withe formula f-subscript c(x)= x^3 + 2x^2 + cx a)graph y= f-subscript c(x) for these values of the parameter c: c = -1,0,1,2,3,4. What are the similarity and differences among the graphs, and how do the graphs change as the parameter...

There have been many QM Interpretation thread, but I haven't found this question answered: Taking aside the fact that a complex probability amplitude is not something we can picture, is the Schrödinger equation local and deterministic at once?

Show that the function f(x) = x^21 + x^11 + 13x does not have a local maximum or minimum. So f '(x) = 21x^20 + 11x^10 + 13. My reasoning is as follows: Since the exponents (10 and 20) are even, 21x^20 and 11x^10 can never be negative, and thus, summing them can never produce a negative...

Number of photons operator can be define as follows: \sum a_k^\dagger a_k . Is it possible to define this operator locally and obtain operator \hat{n}(x,y,z)of local density of number of photons so that \langle \psi |\hat{n}(x,y,z)|\psi\rangle = \rho(x,y,z). Thanks for reply.

Hello I have a local stress acting radial on a thin cylindrical plate (see illustration), how can I calculate if the plate will deform/bend? I can only find equations for uniform external pressure (Marcel Dekker), but will it be okay when the stress is only local?

This is kind of an offshoot from: https://www.physicsforums.com/showthread.php?t=369328 Assume for a second that the controversial experiments are valid and Bell's theorem is true of the universe. I have often seen the philosophical analysis that if Bell's Theorem is true then either local...

Is it correct that theories such as the free complex scalar field or the free Dircac field with their global U(1) symmetry give rise to only globally conserved charges (a globally conserved Noether charge)? If so, how can that be shown? Also, is it somewhat correct to say that the main reason...

Homework Statement I am using the boundary element method to solve unknowns to the Laplace equation from classic potential flow theory for the time evolution of a fluid air interface. At each time step, I need to solve a material derivative equation numerically at every node along an interface...

how can i find the x-coordinates of all local extrema in this equations please anyone could answer it for me? f(x)=x^3+4x^2+2x f(x)=x^4-3x^2+2x f(x)=x^5-2x^2-4x f(x)=x^5+4x^2-4x