Lorentz Definition and 1000 Threads

  1. A

    Understanding the Lorentz Equation: Clarifying the Confusion

    I am confused of how to derive the Lorentz equation x = vt+x'/γ...if x' is the distance to an event according to O' and x is the distance to that same event according to O, then shouldn't the last term be x'γ not x'/γ, since x' is already contracted according to O, so to relate it to x, we would...
  2. A

    Derivation of lorentz transformation?

    I would like to know a simple way of understanding how to derive the Lorentz transformation equations. My book states them without proof and on websites I only see complicated proofs that I am not mathematically ready for yet. Ok so I think i understand x'=γ(x-vt), but let me say it in my own...
  3. Z

    Does a stationary electron in magnetic field experience Lorentz force?

    Homework Statement If an electron is stationary in a magnetic field, will it experience a Lorentz force? Homework Equations The Attempt at a Solution The total vector force (Lorentz force - F) is F = Fe + Fm = Q(E + u X B) The Lorentz force can also be written in terms of...
  4. K

    Time dilation - Lorentz transformation using light clock

    Homework Statement I am trying to derive the time dilation formula using Pythagorean theorem: L = ct (in clocks rest frame) D = ct'(in observer's frame, the clock moving with velocity u) The Attempt at a Solution So D^2 = L^2 +v^2t^2 c^2{t'}^2=c^2t^2+u^2t^2 Sot'=t*\sqrt{1+v^2/c^2}...
  5. D

    Axial anomaly and broken Lorentz invariance

    I had a look at Jackiws article on axial anomaly in scholarpedia: http://www.scholarpedia.org/article/Axial_anomaly Apparently, axial anomaly also breaks Lorentz invariance. Even if this effect would be very weak, doesn't this pull the plug on relativity?
  6. N

    Difference between Lorentz and Einstein

    For Dalespam: The difference between Lorentz and Einstein is that the transformation is only applicable to one frame and must be fully inverse for the moving frame. Lorentz transform into the moving frame but invert the calculation to arrive back at the stationary one. The transformation is...
  7. J

    Lorentz Vs. Einstein Who Wins?

    Lorents and Einstein both made equations to describe time dialation. One of these equations was used in quantum mechanics, the other equation was then used in cosomology. These equations then made two new areas in physics. One describes one area of physics and the other describes an area of...
  8. K

    Lorentz Transform Derivation questions

    I'm trying to follow along with Simple Derivation of the Lorentz Transformation, but am having some hurdles. I'll be referring to step (5) which states: x'=ax-bct ct'=act-bx In paragraph marked 6, I see that the author tries to get eqn (5) to describe motion of the K' frame. This is an...
  9. K

    Is math valid in step 5 of Simple Derivation of the Lorentz Transformation

    I started to study Simple Derivation of the Lorentz Transformation In this derivation, I gather that there are two rays of light being tracked--one going to the right of the origin and one going to the left of the origin. The right-going light is described by x=ct and x'=ct'. The...
  10. H

    Special Relativity (1-dimensional Lorentz Transformation)

    Homework Statement During class today, I was told that: x' = γ(x-vt) y' = y z' = z t' = γ[t-(v/c2)x], where γ=(1-v2/c2)-1/2 (This is just the standard Lorentz transformation.) Then I was told that we could find dx/dt, the inertial velocity, by finding dx' and dt' and dividing...
  11. A

    Special Relativity. How to use the Lorentz Transformation?

    γHomework Statement Stan is at rest on the Earth while Mary is moving away from the Earth at a constant speed of 0.600c. Stan and Mary start their timers when Mary passes Stan (in other words, t = t' = x = x' = 0 at that instant). (a) When Mary has traveled a distance of 0.900 *108m...
  12. J

    Plot Real & Imaginary Dielectric Function: Lorentz Model

    Plot the real & imaginary parts of dielectric function.
  13. H

    Covariant and noncovariant Lorentz invariants

    It recently came to my attention that there exists two "kinds" of Lorentz invariants: the covariant and the noncovariant ones. The covariant ones would be Lorentz scalars e.g. fully contracted Lorentz tensors. If one applies the Lorentz transformation to a covariant Lorentz scalar, one would...
  14. S

    Confused by proof of Lorentz properties from invariance of interval

    I've seen a few short proofs that if that some transformation \Lambda preserves the spacetime interval, then \Lambda^\top g \Lambda = g where g is the spacetime metric. They have all relied on an argument using some simple algebra to show that (\Lambda^\top g \Lambda) x \cdot x = g x...
  15. W

    Generators for Lorentz transformations

    Consider Minkowski spacetime with signature (-+++) and coordinates (ct,x,y,z) with respect to the standard orthogonal basis. I'm looking for the smallest set of matrices that can generate any Lorentz transformation with respect to this basis. I came up with 8 matrices (see below). Am I missing...
  16. C

    Time Contraction in Lorentz Transforms?

    The question I have is to do with the Relativity of Simultaneity of the type described by Einsten; whereby two light emitters are placed pulsing once every millisecond on board a spaceship traveling at the speed of light. One of these lights faces forward and the other faces aft. If time dilates...
  17. J

    How Do Lorentz Transformations Affect Light Signal Velocities?

    Homework Statement Consider a light signal propagating in some arbitrary direction, with vx \neq 0 vy \neq 0 vz \neq 0 and vx2 + vy2 + vz2 = c2 Use the Lorentz transformation equations for the components of velocity to show that v'x2 + v'y2 + v'z2 = c2 Homework...
  18. S

    Lorentz Law field equation applied in a field

    Homework Statement An electron is traveling at 5.0 × 106 m s−1 directly into the page at the point P shown in Figure 3. P is 4.0 cm from O. Again, D = 10 cm and the current i in each wire has magnitude of 1.0 A with the directions that you found in part (c). Find the magnitude and direction of...
  19. W

    Poincare vs Lorentz Group

    The words Poincare and Lorentz sound pretty elegant. I think they are French words like Loreal Or Laurent. I know Poincare has to do with spacetime translation and Lorentz with rotations symmetry. But how come one commonly heard about Lorentz symmetry in Special Relativity and General...
  20. 1

    Can Lorentz force be expressed as a function of z in a static electromagnetic field?

    Hi, I have a particle moving in a static electromagnetic field in which E and B have the following components: E=(Ex, 0, 0) B=(-Bx, 0, 0) and both depend on z, namely Ex(z) and Bx(z). The particle is moving along z with constant velocity v=(0, 0, vz). If I want to express Lorentz force...
  21. R

    Direct observation of lorentz length contraction

    There is a train(think of having only two boggie for a claer visualization ) in which two rod which are attached to the front and rear end of the train(say, the length between these rod is the length of the train). These are lowered by a single lever to touch the ground. These rods are at...
  22. S

    Lorentz Contraction: Gaining Mass & Shrinking

    Hi all, modern physics student here. If the Lorentz contraction occurs at relativistic speeds, how does it gain mass yet get shorter? The best I can think of is that it has to depend in which reference frame one is in at the time. Does anyone know any useful links where I can read about this?
  23. E

    Lorentz Boosts in Group Representation (from Weinberg)

    Alright, so excuse my ignorance, but I have no idea why the choice he uses for boosts is "convenient" Just to make sure everyone is on the same metric etc etc. Weinberg uses (-,+,+,+) with gamma defined traditionally and God-given units He requires that transformations..(oh my,,,how...
  24. J

    Quick question about Ampere's Law and Lorentz force law

    Btw I am obtaining all these equations from chapter 5 of Griffiths text. Lorentz force law is: Fmag = ∫I(dI x B) Does this give the force on a current carrying wire due to an external magnetic field? (i.e. has nothing to do with own wires magnetic field) I think the answer is yes since the...
  25. A

    Lorentz Contraction/ Simultan Problem

    Hi all, this is not a HW problem but one I made up myself, (so you won't find it in any txtbooks or solutions etc.). It also is much more advanced than for someone on the physics HW site, as I can see, so I thought it best to put here. I'm having trouble working out simultaneity and Lorentz...
  26. S

    Does the Lorentz Force Account for Radiation Loss in Charged Particles?

    when a charge particle is moving in electric and magnetic field, a force exert on this particle is Lorentz force. when this force apply to this particle, it accelerate and we know accelerated charge particle radiate. when a particle radiate an electromagnetic wave ( photon ) lose it's...
  27. E

    Find Generators of Lorentz Group: Jackson's List & K Matrix

    Hi! I'm trying to find the generators of the Lorentz group. Jackson lists them all, for example, the generator of a boost along x is: K=\left( \begin{array}{c} 0\;1\;0\;0 \\ 1\;0\;0\;0 \\ 0\;0\;0\;0 \\ 0\;0\;0\;0 \end{array} \right) Now, what I don't understand is: this matrix is a...
  28. Y

    Lorentz Transformations For Particle In Uniform Electromagnetic Field

    Homework Statement A charge q is released from rest at the origin, in the presence of a uniform electric field and a uniform magnetic field \underline{E} = E_0 \hat{z} and \underline{B} = B_0 \hat{x} in frame S. In another frame S', moving with velocity along the y-axis with respect...
  29. Z

    Lorentz Length Contraction Derivation

    In this video: Special Relativity: Length contraction in more detail http://www.youtube.com/watch?v=s3ZqBt8KWVQ&feature=mfu_in_order&list=UL for the derivation of Lorentz contraction equation at 2.48 the guy says, "I won't bore you with the details". I'd appreciate is someone would...
  30. S

    Inhomogeneous (poincare) lorentz transormation

    I'm reading a physics book and in the section on relativity they are using the Einstein summation convention, with 4vectors and matrices. They say that the transformations take the form: x^{\prime\mu}=x^{\nu}\Lambda^{\mu}_{\nu}+C^{\mu} where it is required that \Lambda^{\mu}_{\nu} satisfy the...
  31. O

    Representations of lorentz group and transformations IN DETAIL

    From Peskin and Schroeder: The finite-dimentional representations of the rotation group correspond precisely to the allowed values for the angular momentum: integers or half integers. From the Lorentz commutation relations: \left[J^{\mu \nu},J^{\rho \sigma}\right]=i \left(g^{\nu \rho}J^{\mu...
  32. G

    Exploring the Lorentz Force: Its Origin and Effects

    hi i was wondering whether the lorentz force is just caused by the fact, that moving charges produce a magnetic field, just like every current does, and this magnetic field interacts with the magnetic field in the environment, that causes the force or whether the lorentz force has nothing to...
  33. R

    General form of a Lorentz transformation

    I got the general form of a Lorentz transformation in a GR book, {\textbf{x'}} = {\textbf{x}} + (γ-1)\frac{{\textbf{x}•\textbf{v}}}{v^2}\textbf{v}-γ\textbf{v}t t' = γ(t-\frac{{\textbf{x}•\textbf{v}}}{c^2}) from frame S to frame S' moving with relative velocity \textbf{v}. How to...
  34. J

    Mini black hole not Lorentz invariant?

    Let's say that we have a particle flying through space, at a collision course with a planet. As seen from an observer on this planet, the particle has an enormous energy, and its wavelength is just slightly bigger than the Planck length. As the particle falls down the gravitational well of the...
  35. Demon117

    The set of Lorentz boosts and space rotations form a group

    Ok. I understand that the set of Lorentz boosts and space rotations is equivalent to the set of Lorentz transformations. I understand that they form a group, but what I cannot seem to grasp is this. What the explicit form of such 4x4 matrices? One needs to know this in order to show that the...
  36. O

    Verifying Lorentz Algebra with Clifford/Dirac Algebra

    Paraphrasing Peskin and Schroeder: By repeated use of \left\{ \gamma^{\mu} , \gamma^{\nu} \right\}= 2 g^{\mu\nu} \times \textbf{1}_{n \times n} (Clifford/Dirac algebra), verify that the n-dimensional representation of the Lorentz algebra, S^{\mu...
  37. T

    Lorentz Transformation with Two Moving Frames

    Homework Statement Essentially, a particle is moving downward from the top of a tower at 0.98c, and the tower is moving up at 0.98c. I am to find the apparent height of the tower from the perspective of the particle Homework Equations Δx=γ(Δx′+vΔt′) Δt=γ(Δt′+vΔx′/c2)...
  38. S

    Lorentz Transformation of Fields

    I am reading Quantum Field Theory by Michio Kaku, and I have come across some equations that I can't quite make sense of. I am hoping somebody can help me out. Please see attached. Thanks.
  39. L

    Lorentz Force: Opposite Currents and Positive Charge Carriers

    'One example of the Lorentz force is that, if two parallel wires are carrying current in the same direction, the wires will be pulled toward each other. The Z-pinch uses this same effect; the entire plasma can be thought of as many current-carrying wires, all carrying current in the same...
  40. A

    Lorentz Transformations Acceleration: A simple problem

    Hi all, I came up with the following problem myself and am trying to solve myself. I haven't seen it in any txtbook, grad or undergrad. Suppose you have the ground frame (Earth). Earth sees ship1 start at t=0, v=vo1, at x=xo1. Earth sees ship2 start at t=0, v=vo2, at x=xo2 All...
  41. S

    Relevance of Local Lorentz Invariance Violations

    What is the relevance of Local Lorentz Invariance Violations if they would be detected in any future experiments? Does it mean there is absolute space and time in the microscopic sector below where current experiments can't probe or other absolute parameters since there would be preferred frame...
  42. W

    Noob question about lorentz factor

    Hello So i saw this video on youtube explaining some basics of general relativity and they used example with 2 rockets moving paralelly with laser pointed from rocket A to mirror on rocket B. Heres my picture of it :D Where we are stationary observer watching those two rockets A and B...
  43. Q

    Charge Invariance & Mass Dependence: Lorentz Transformations

    Why is it that charge is Lorentz invariant (it's a scalar, independent of the frame of reference) whereas mass is not? Does this mean that the gravitational force a body exerts depends on the frame of reference, whereas the electric force doesn't?
  44. C

    Gamma5 x d^2 Lorentz invariant?

    is \overline{\Psi} γ5 \partial2 \Psi Lorentz Invariant? How does this term transform under Lorentz transformations? Here \Psi is a Dirac field. Thanks
  45. C

    EPR and Lorentz transformation

    Hello I have been thinking at EPR experiment during some time. It is very suggestive for me that the entanglement effects travel faster than ligth between the positions of 'Alice' and 'Bob'. I understand this is not contradictory with special relativity, due there is a not real exchange of...
  46. J

    Proving the Lorentz invariance of an integration measure? QFT related?

    So, first off, I'm thinking Lorentz invariant quantities are the same in any inertial frames S and S' regardless of their relative velocity. I'm thinking I need to show that \frac{d^3k}{(2\pi)^32E(\vec{k})} = \frac{d^3k'}{(2\pi)^32E'(\vec{k'})} where the primed & unprimed quantities denote...
  47. L

    Galilean and Lorentz transformation

    1. What is the limitation of the Galilean transformation? 2. What are difference between Lorentz transformation and Galilean transformation?
  48. B

    Does the Magnetic Field Affect the Dielectric Constant in the Lorentz Model?

    Hi I read in text for calculation dielectric constant in Lorentz model, we only regard electric field that coupled with each oscillator. So the magnetic field of input wave has no effect in calculation of dielectric constant in this model?
  49. A

    The Lorentz Transformations and a Few Concerns

    The derivation of the Lorentz transformations is based on the homogeneity[of space and time] and the isotropy of space. Could one derive the same transformations wrt space which is not homogeneous or[not] isotropic? You may consider a few chunks of dielectric strewn here and there. I am...
  50. C

    Relative length and velocities using Lorentz transformations

    Homework Statement Space ships A and B, each having a proper length of 100m, pass each other moving in opposite directions. According to the clocks on ship A, the front end of B takes 1.5 x 10^(-6) s to pass the entire length of A. a) what is the relative velocity of the two ships? b)...
Back
Top