Local Definition and 521 Threads

I've been looking all over and it appears like I may be using the wrong words to really get a solid answer. I figured I would ask here and maybe someone could either give me a few better terms to help my search or would know the answer already. Thanks in advance! I'm working with a team...

Hi, Bell says there is no local realistic theory that reproduces the (experimentally verified) predictions of QM. That leaves us with three possibilities: 1. Non-local non-realistic (e.g. Copenhagen interpretation) 2. Non-local realistic (e.g. Bohmian mechanics) 3. Local non-realistic...

Homework Statement . Let ##f:ℝ→ℝ## be an open and continuous function. Prove that f doesn't have local extrema The attempt at a solution. I suppose there is some ##x_0 \in ℝ## and some ##ε>0## such that ##f(x_0)≤f(x)## for all ##x \in (x_0-ε,x_0+ε)## (the proof for relative maximum is analogue...

Can anyone help me with Ex 4.1 in MTW? What is a 'generic' field? My expectation is that it would comprise an Electric Field, with arbitrary direction, a Magnetic Field, also with arbitrary direction, and a radiation field (E and B of equal magnitude) , radiating in an arbitrary direction...

I just found out if I want to transfer to a UC I will have to take 3 years at my local community college. Is it reasonable to go talk to professors at the local university (Cal Poly SLO) and see if I could do research with them? I do not really have much to offer them other than a dedicated...

Hi everyone! I would like to ask you some clarifications on an explicit example of local trivializations and transition functions of fibre bundles: namely on the [-1,1]\hookrightarrow E\rightarrow S^1 bundle (which I guess is the simplest possible example). Following Nakahara (chapter 9...

I struggled long and hard to resist the idea that Alice observes nothing special as she falls into the Schwarzschild horizon of a BH. Now, I accept it. The thing that did it for me was professor Susskind's description of deSitter space, and how the math of the metric for the cosmological...

Local Electrodynamics in higher dimensions?? So I am an unexperienced undergrad but the other day I had a few thoughts which are most likely crazy. I'm just wondering why they don't work. And whether the questions I'm asking are answered elsewhere. So I've heard: (i) Maxwell's...

I understand it from a classical viewpoint, like the flow of a fluid. But shouldn't an electron obey the rules of QM? How is teleporting from one place to another forbidden in QM, wat about tunneling.Where is your continuous flow now? What about Quantum Entanglement. I don't get it.This...

(My last https://www.physicsforums.com/showthread.php?p=4424810#post4424810 post did not get much attention so I try again without all these formulae. Think this will be more clear...) To derive the local field in a non-polar dielectric you assume a very small spherical cavity in which (since...

Hi, in some texts, the term supergravity refers to locallized supersymmetry but most of the times, I have the impression that it refers to gravity mediated supersymmetry breaking (i.e. higher dimensional terms in the kahler- and superpotential that are suppressed by powers of the Planck...

ΩHomework Statement Given the metric ds^2 = \frac{dx^2 + dy^2}{y^2} find a set of coordinates which yield local flat space. i.e. ( g_{\mu\nu} = \delta_{\mu\nu} + second order terms). My text outlined a process to go through to find the flat space coordinates, but the actual execution is...

Homework Statement At room temperature the relative permittivity (ε) of water is 80. The dipole moment of a water molecule is 6.2×10-30 coulomb meters. What is the average value of Elocal/E for a water molecule? (In working out this problem, neglect the contribution to the relative...

I spent days trying to find this information on the internet, but i think i will never find it, so i came here looking someone who knows it. The Mystery is : Where is the Gravitational center of the Local SuperCluster (Also known as Virgo SuperCluster) ? Some Usefull information that i...

The equivalence principle implies that it's always possible, by an appropriate coordinate transformation, to locally transform away the effects of gravity by going into a freely falling frame. Furthermore the local flatness theorem implies that it's always possible to but the metric ##g_{\mu...

Hey guys. I'm having doubts about something in a GR text I read (Gravitation - T.Padmanabhan). In general, for Lorentzian 4-manifolds, we call a basis of smooth vector fields ##(e_{\mu})^{a}## (that is, a set of smooth vector fields that define a basis for the tangent space at each event of...

As the only thread I've ever started before (https://www.physicsforums.com/showthread.php?t=369328 ) attracted a lot of interest, became one of the most viewed threads in the forum, and was closed :-), I'd like to make a short update here. I have published a new article on the topic: "No...

Hi All, I am interested in the discussion in section 10.5 of Schutz's First Course in GR book. Specifically, the conditions at r = 0 of a static, spherically symmetric interior star (or whatever) solution e.g. Schwarzschild interior solution. He argues that by enforcing local flatness one...

Homework Statement ds^2 = g_{tt} dt^2 + g_{tx} (dt dx + dx dt) with g_{tt} = -x and g_{tx} = 3 "Show that this is indeed a spacetime, in the sense that at every point, in any coordinates, the matrix g_{\mu \nu} can be diagonalized with one positive and one negative entry. Hint: You...

Jacobi identity in local coordinates?!? Apparently (i.e. according to an article written by physicists), the Jacobi identity for the Poisson bracket associated to a Poisson bivector \pi = \sum\pi^{ij}\partial_i\wedge\partial_j is equivalent to...

Also how can local causality be violated?

Greetings Physicists, I've been accepted to study at my state University for my Ph.D in Physics. I reticent to accept however for two reasons; 1. They are not offering me a TA'ship immediately. This means I would have to finance at least my first year with student loans and work study...

Say Alice gives Bob the wave-function, a momentum eigenstate, of a charged particle. Bob then makes a local gauge transformation on the wave-function, ψ --> exp[iqθ(X,t)]ψ. Can Alice now undo the local gauge transformation with the right addition (or subtraction?) of electromagnetic...

Hi, I need some help with interpreting an altitude vs local time graph. http://img401.imageshack.us/img401/4871/astronomygraph.jpg is a link to the graph and some of the questions that were asked about the graph. also this information was provided: Date of observation: christmas night...

Hi I have some function f = f(x1,x2,...xn) over some domain [0,1]^n, and I'd like to find the global minimum. The function is *highly* non-linear and takes about 1 second to evaluate. I know it's positive because it's the sum of squares of about 1,000,000 arguments, each of which pretty much...

Here is the question: Here is a link to the question: Calculus homework help?!? - Yahoo! Answers I have posted a link there to this topic so the OP can find my response.

How to do local Physics Analysis ?? You Know all the LHC machine at CERN, and the CMS detector (Compact Muon Solenoid) This detector run a CMSSW ( CMS Software ) on CERN machines, can i download that software on my local machine, run it and do physics analysis? if yes how to download it, and...

Hi everyone, I met a specific semilinear second-order PDE given by \frac{\partial u(x,t)}{\partial t} = {\bf A}(x,t) u(x,t) + U(x,t) u(x,t)^{-p} + A(x,t),...(1) u(x,0) = b>0, where p>0,\ \ (x,t) = (x_1,x_2,t)\in{\bf R}_+^2\times [0,T] , and {\bf A}(x,t)u =...

Homework Statement A person whose mass is 150lb weighs 144.4 lbf. Determine a) the local acceleration of gravity, in ft/s2, and b) the persons mass, in lb and weight, in lbf, if g = 32.174 ft/s2 Homework Equations F=ma The Attempt at a Solution A) Using F=ma I got 144.4 lbf =...

These are notes I made when I was studying the subject 20 years ago. They seem fine considering that I was student then. I believe they can be useful for those who are studying Yang-Mills and other related material. Sam

I have recently read a few things about the local interstellar clouds and while I am by no means a science expert, math and science were my strong points. After reading about this a few things occurred to me, and they seem to be bad for our solar system. The clouds are ~10,000° C, our solar...

Let me start this off by informing you a little about myself. I am a Freshman at my local community college. I am majoring in Biological Science (that's the only science major of study here; kind of covers it all.) I am majoring in Physics as my field of study, however. Physics has always...

Homework Statement Which of the following sets of equipment cannot be used to measure the local value of the acceleration due to gravity (g)? (A) A spring scale (which reads in force units) and a known mass. (B) A rod of known length, an unknown mass, and a stopwatch. (C) An inclined...

I've been working on a decentralized algorithm for finding local minima. Can anyone give me a few examples of mappings of the form F:R→R that have multiple local minima. I'm having problems defining neighbourhood on mappings from R2→R, so I thought I'll test it out on single variable functions...

Knowing the dielectric constant of a medium we can earn the electric field at any point in that medium which is deferent from the applied external electric field. So why do we use the Local field correction?

Homework Statement Find the local extrema of the function f(x)=(x^3-2x-2cos(x))Homework Equations derivatives, some algebra The Attempt at a Solution Well, the concept is simple. Solve for the first derivative and set it equal to zero: dy/dx=2sin(x)+3x^2-2=0 and Next, solve for x to...

The coordinate speed of light relative to its speed at infinity is calculated as (1-2M/r)c (at infinity) yes?? SO it makes sense that local measurements made with local rulers and clocks which are contracted and dilated respectively would still be c for radial measurements. But how does that...

Hi everyone! :smile: I'm newbie in this forum, please help me for my question. In differential equation we know that the differential equation has a solution and uniqueness. which is usually called the existence and uniqueness theorem. my question, what is the difference of local existence...

Homework Statement Why is 'a' not a local maximum? Homework Equations The Attempt at a Solution According to the definition of a local maximum, I have to take an open interval around 'a' so it seems like 'a' is a local maximum. I don't understand why it isn't.

Homework Statement Assume that the polynomial P(x) has exactly two local maxima and one local minimum, and that these are the only critical points of P(x). Sketch possible graphs of P(x) and use them to answer the following. (e) What is the sign of the leading coefficient of P(x)? positive...

I tried doing a google search on this and couldn't find the information I was looking for. My first undergrad was in Intelligence Analysis (I was MI in the Army) and now in my 4th year as a Business Student and I've gotten the math bug. I'd like to avoid high costs of school (my current...

Homework Statement Find the local max/min or saddle points of f(x,y) = (x-y)(1-xy) Homework Equations The Attempt at a Solution I expanded the equation to f(x,y) = x-y-(x^2)y+xy^2. Then I found the partial derivatives of the function. fx = 1-2xy +y^2 fy = -x^2-2xy I'm...

Hi guys. Today was my last day of Calculus I class, and I’ve had this question simmering in my mind for some time now. Perhaps you guys may enlighten me or point me in the right direction? Consider the Weierstrass function, which is continuous everywhere but differentiable nowhere. We know that...

Hi, I'm currently reading Manfredo do Carmo's "Differential Geometry of curves and surfaces" and I'm stocked with problem 2 of section 2-6 which is "Let S_2 be an orientable regular surface and \varphi:S_1 \rightarrow S_2 be a differentiable map which is a local diffeomorphism at every p \in...

hi everyone, I have been trying to understand gauge theory. I am familiar with the Noether's theorem applied in the context of simpler textbook cases like poincare invariant Lagrangians. This is my question: Are there Noether currents corresponding to the local gauge symmetries too and would...

General relativity says that nothing can go faster than the speed of light when measured against local landmarks. What counts as a local landmark? What is the boundary between a local and distant landmark?

Pretty elementary question here, but I'm new to astronomy and I'm having trouble estimating LST. Online sources give me the exact formula, but this doesn't really help me on the fly. My location is 97.7-ish degrees W of Greenwich, which I know means I can subtract roughly 5.5 hours from Sidereal...

Homework Statement f(x)={0 for x<0, \sqrt{x} else} a) Is f(x) globally Lipschitz? Explain b) Find the area for which f(x) is locally Lipschitz. Homework Equations The Attempt at a Solution a) f(x) is not globally Lipschitz in x on [a,b]xRn since there is a discontinuity at x=0. b) I would...

Can somebody explain in layman's terms the connection between local flat space (tangent planes) on a manifold and the Riemann tensor.

I am familiar with basic calculus of variations. For example, how to find a function that makes some integral functional stationary (Euler-Lagrange Equations). Or for example, how to perform that same problem but with some additional holonomic constraint or with some integral constraint. The...