Lorentz Definition and 1000 Threads

Homework Statement Consider the Lorentz transformations: ct' = gct - Bgx x' = gx - Bgct y'=y z'=z Show that the primed frame corresponds to a "rocket" frame moving at speed v in the x direction relative to the unprimed frame. (Sorry about my notation: g = gamma) Homework...

the title is pretty clear, so we have this F=q( E+V/c X B) the force for a point charge q in an electromagnetic field. and we have the formula to the hamiltonian of electromag force: H= (P+ q/c.A)/2m _ e\phi. the question is how can I get the F from the hamilton principle, using the...

What if someday we would have news that Lorentz Invariance Violation was detected? Is this possible at all? But our Special Relativity is based on Lorentz Invariance and the more general General Covariance in General Relativity. Does this mean that Lorentz Invariance violation is almost...

c^2 occurs frequently in special relativity: in the Lorentz transformations, in forumlas for the interval, relativistic energy, and others too. Is there an intuitive reason for the high occurence of c^2?

Homework Statement From Lorentz Transform, x^{\prime} = \gamma (x - vt) From textbooks and wikipedia, L_0 = x'_2 - x'_1 = \gamma (x_2 - x_1 ) Where x_1 and x_2 = L Thus, \L_0 = \gamma L Question is this: If i take the same method and us the Inverse Lorentz transform, i seem to...

In my EM course I've encountered what is called the "Lorentz contrast". If I derive the wave equation using the scalar and vector potential, I end up with a non-homogenous wave equation with the term: (left hand side), or more precisely, the divergence of said term. What does it mean...

Homework Statement Frame S and S' are moving with respect to each other in the x-axis with some velocity. An event happens in S' at x'_1 = 1.0 c*year at t'_1 = 1.0 year. Another event happens at t'_2 = 2.0 c*year at t'_2 = 0.5 year. The two events are simultaneous at some point in S. The...

Homework Statement Observer O sees a fire-engine leave its station 6363 m due north from Cape Canaveral, where the super-shuttle Lorentz had been launched 10^-5 s earlier. A space-cruiser flying north-east sees these two events also 10^-5 s apart, but with the shuttle launch occurring after...

Hi, Would someone know where I can find a derivation of the lorentz-invariant lagrangian density? This lagrangian often pops-up in books and papers and they take it for granted, but I was actually wondering if there's a "simple" derivation somewhere... Or does it take a whole theory and...

Sorry if I should be posting as homework, but it's not homework anymore and I'm just curious about the answer. My question is simple and doesn't require answering the actual homework question I had. If there is a force on a charge in one inertial frame of reference, will there also be a force...

A vector in special relativity is the quantity: V = V^\mu \hat{e_\mu} On a change of coordinates, the basis vectors co-vary with the coordinate derivatives: \hat{e_\mu'} = \frac{\partial x_\mu'}{\partial x_\mu} \hat{e_\mu} The vector elements are the opposite. They are said to be...

Is it possible that Lorentz invariance is just a lower limit of a larger manifold that has a priveleged frame? Even if Bell's experiments can't transmit signal faster than light. The spirit of relativity is still violated by say instantaneous correlation between 10 billion light years. As...

And if so, How? From the post 15 and 16 of the thread https://www.physicsforums.com/showthread.php?t=474719" But total charge and total current, Q and I, do form a 4-vector, don't they? There seem to be two ways to solve this, but I can't figure out which one is right. Properly...

Homework Statement A particle moves at speed u_{x}= +0.0c according to an observer in the frame S. a)Calculate the velocity of the particle, u_{x}'_{Gal} and u_{x}'_{SR} as measured by an observer in S'. Let \beta range from -0.95c to +0.95c in increments of 0.05. Put your results in a...

Homework Statement Derive the Lorentz transformation by assuming that the transformation is linear, and does not change the perpendicular coordinates. Write the transformation as x' = A1 (x - vt), y' = y, z' = z, t' = A2 t + A3 x, Determine A1, A2, A3 by requiring that a flash of light...

Two observers A and B are in relative motion with a constant velocity[for example, along the x-x' direction].If A knows the the position of B accurately , the motion of B gets enormously uncertain[and vice verse] in his calculations/considerations.How is he going to derive the Lorentz...

Let us consider the B-E and F-D statics: {<}{n}_{i}}{>}{=}{\frac{1}{{exp}{(}{{\epsilon}_{i}{-}{\mu}{)}{/}{kT}}{\mp}{1}} Now we observe the formula from a boosted frame.The left side is a scalar and should not change in response to the Lorentz transformations.What about the right hand side?The...

Homework Statement A is at the base station and given in K co-ordinates B is on a spacecraft and given in K' co-ordinates. The velocity of the spacecraft is v=0.8c Question 1 After t = 2y (y = years) A sends a message by radio to B demanding a picture. Which time t' does B have when...

A 'cause' occurs at point 1 (x1, t1) and its 'effect' occurs at point 2 (x2, t2) as measured by observer O. Use Lorentz transformation to find t'2 - t'1 as measured by O' and show that t'2 - t'1 >= 0. that is Observer O' can never see the effect before the cause. I know that is possible to...

Can anyone explain how Lorentz factor is defined (the one from theory of diffraction, not special relativity)? I read that intensity of diffracted beam is proportional to Lorentz factor, but I could not find its definition. On what parameters does the Lorentz factor depend? How does the...

Hello, I've been trying to puzzle this one out and even the mighty internet has not been particularly helpful, so here goes: Say you have a current carrying copper wire perpendicular to a magnetic field. Let's give some values for clarity: the length of the wire is 1m, the current is 3A...

Hey all, Simple question, so hopefully it gets answered quickly. I hate SR, but am marking an assignment on it. Here's the set-up Alice is standing still on a train traveling at 3/5c and Bob is on the platform at rest. A series of lights are set up along the track, yada yada. Bob sees...

Is there a way to derive Lorentz transforms by knowing just Galilean/Newtonian relativity (adding up velocities) and Pythagoras theorem? I do not understand the principle of homogeneity or any higher mathematics. I can derive t' = gamma * t by using common sense and Pythagoras theorem. I am...

Basically the question is about a penning ion trap. You need to use the equation for the Lorentz Force, which I have. It says the trap electrodes have a potential: V(x,y,z) = A(2z^2 - x^2 - y^2); There's a superimposed uniform B-Field B = B(z hat) It then asks you to write down an...

When you start in the rest frame of the electron, the Spinor w(p = 0) = (1 0 0 0 ) represents a positive energy state with spin up in the Z direction u = (0, 0 0 1),, that is the spinor is an eigenspinor of the operator S . u, where S is a 4 dimensional operator (S0, S) after a Lorentz...

Hello! Hopefully somebody could give me a push from behind on this one :) Homework Statement Show that the classical wave equation is lorentz invariant. The Attempt at a Solution I tried to exchange all derivatives by the chain rule: (c^2 \frac{d^2 }{dt^2} + \frac{d^2 }{dx^2} + \frac{d^2...

Hi, I'm reading a book on SR/Field theories that simply posits the space-time interval and from that defines a Lorentz transform as any transformation which leaves the interval invariant. My question is how do we posit the space-time interval in this manner using only the postulates of...

Hello! need some help with length contraction. So according to lorentz transformation we got I don't know how to put symbols so ill use Y as gamma since they look alike :) dx' = Y dx - u Y dt So proper length refers to the frame where dt = 0 since u are measuring the ends at the...

System K: x=a t=2a/c x'=2a t'=3a/c I need to figure out in what frame K' will these events appear to occur at the same time? I know the answer is c/2 in the -x direction but finding I'm having a hard time finding the velocity. I really confused on how to get the velocity out from...

hey, I heard about improper Lorentz transformations, but I did not really understand what they are. I just know that their determinant is -1, but what does this physically mean? Can somebody explain this to me?

http://arxiv.org/abs/1102.2784 New Limits on Planck Scale Lorentz Violation from Gamma-ray Burst Polarization Floyd W. Stecker 3 pages, submitted to Phys. Rev. Letters (Submitted on 14 Feb 2011) "Constraints on possible Lorentz invariance violation to first order in E/M_{Planck} for photons...

Homework Statement 1The rockets of the Goths and the Huns are each 1000 m long in their rest frames. The rockets pass each other, virtually touching, at a relative speed of 0.8c. The Huns have a laser cannon at the rear of the rocket that shoots a deadly laser beam at right angles to the...

Greetings everyone, I understand the derivation of the Lorentz transformations, and have not had trouble applying the concepts and the math to most elementary SR problems. However, something occurred to me recently which I have been unable to resolve. Let’s say there are two tennis balls...

Hello This is a part of a simple paper about special relativity [PLAIN]http://img15.imageshack.us/img15/8789/91001769.jpg I don't understand the assumption in the red box .. why are they all squared ? thank you

I'm new here and I have checked the FAQs. I'm not sure if this question has been posted before. This may actually be a silly question. Why do we study Lorentz and Poincare Groups? I have studied a bit of the theory but was wondering what exactly are we talking about when we study the...

The Lorentz transformation are given by (see the attachment) x'=(x-vt)/√(1-v^2/c^2 ) t'=(t-vx/c^2)/√(1-v^2/c^2 ) Let us transform the event (10^100 m,1sec) in the x-frame to the x'-frame that is moving in the usual geometry with the speed v=10^(-10) c. Could you see that that t'≈-10^81...

Homework Statement i) Show that the wave equation: [( -1/c^2) d^2/dt^2 + d^2/dx^2 + d^2/dy^2 + d^2/dz^2 ]u(t,x,y,z) = 0 is invariant under a Lorentz boost along the x-direction, i.e. it takes the same form as a partial differential equation in the new coordinates. [Use the chain rule in two...

Hello I have been having trouble understanding equation 14.25 in Bjorken and Drell "Relativistic Quantum Fields" and how exactly it gets to it. Also I would like to explicitly find/derive what the operator gauge function is. Can anyone help please?

Homework Statement Event A occurs at xA = 500m. Event B occurs 5 microseconds later at xB = 1500m. With what speed must an observer move in the positive x direction so that the events occur at the same point in space in the observer's frame?Homework Equations Lorentz transformation...

Homework Statement A3. Show that the Lorentz transformations on a spacetime 4-vector can be written as x'μ = (Lμν)*(χν) . Find the matrix L. Prove that (in matrix notation) Lτ gL = g where g is the Minkowski spacetime metric.Homework Equations Any help suggesting at least equations will be...

Hello. When one is converting between coordinate systems, the Jacobian arises as a necessary consequence of the conversion. Does this occur with transformations between relativistic systems, and, if so, is this manifested through the prevalence of gamma in the transforms? Any guidance would...

I'd like to start by mentioning that I have very little in the way of experience on the subject, so forgive me if my confusion is somewhat trivial.. My problem lies with understanding what the fundamental variables in the Lorentz Transformations actually represent. For example, it is to my...

In the process of proving that the d'Alembert operator https://www.physicsforums.com/attachments/31306 is invariant under Lorentz transformations, it was required to commute two terms in the following expression for the transformed operator, which was obtained by switching the index on the...

I don't understand why the lorentz factor is 1/[1-(v2/c2)]1/2 http://www.softcom.net/users/greebo/dila.jpg clearly you reach something different here.. i really don't get this, I'm sure it's something very simple

How is Lorentz invariance handled in GR? I know that there is no global Lorentz invariance in GR, instead it only holds locally, meaning that it is obeyed in the limit at infinity:when r goes to infinity by considering infinite distance or infinitely small point mathematical objects. But when...

Homework Statement Given that (φ/c,A) is a 4-vector, show that the electric field component Ex for a Lorentz boost along the x-axis transforms according to Ex' = Ex. Homework Equations E_x = -\frac{\partial \phi}{\partial x} - \frac{\partial A_x}{\partial t} A_x being the x component of the...

I'm trying to teach myself special relativity. I use the book 'Introduction to Special Relativity' by Wolfgang Rindler. I have a question about length contraction. We consider 2 particles traveling along the x-axis of a reference frame S with a constant distance between them. We can always go...

I have a question about the way lorentz transformations work with respect to a 'block' view of the universe. Take our universe as a 3d chart with 2 space dimensions and one time dimension (ignoring the other space dimension for simplicity). You chart it using some "god's eye view" reference...

Homework Statement 2 particles are created in a high-energy accelerator and move off in opposite directions. The speed of one particle, as measured in the laboratory is 0.650c, and the speed of each particle relative to the other is 0.950c. What is the speed of the second particle, as measured...

"Locally Lorentz" Mister Thorne Wheeler, "Gravitation" asks "What does it mean to say that the geometry of a sufficiently limited region of spacetime in the real physical world is Lorentzian?" The follow this up with two answers, neither of which appears to have much to do with the question...