Lorentz Definition and 1000 Threads

  1. P

    Why Does t' Include vx/c² in Lorentz Transformations?

    I understand x' = λ(x - vt) but why does t' = λ(t - vx/c^2)? where does the vx/c^2 come from? and honestly I don't understand what t' is. because from what I understand is that t' is the length of time t as observed from the reference frame S'. which means t' = t*λ?
  2. TobilobaEinstein

    B Deriving the Lorentz transformations

    I have tried to derive the lorentz transformations but there is a part of it that requires substitution into two equations when t=0. How do I do that
  3. N

    B Understanding Final Form of Lorentz Transformations

    In my last post I asked about the general form of the Lorentz Transformation for time. Now I am trying to understand the final form of it, and how it makes sense based on what's happening physically. The final form for t is: t = γt1 + (γv/c2/)x1 It's the second part of this equation, the...
  4. Pencilvester

    I Lorentz Transformation Derivation: Assumptions Req'd?

    In deriving the Lorentz transformation, is it required to assume that the transformation to get from coordinate system ##\bf {x}## to ##\bf {x’}## should be the same as that to get from ##\bf {x’}## to ##\bf {x}## (with the simple correction of flipping the velocity)? If no, could someone...
  5. Wein_Sim

    Reaction Force of Lorentz Force

    Hi everyone, in school we recently learned about the Lorentz Force, which says that when charged particles move through an electric field (perpendicular to the field lines), a force is excerted on them (called the Lorentz Force), which goes perpendicular to both the magnetic field lines and the...
  6. S

    Detecting Lorentz Force: Experiment with Strong Neodymium Magnet

    I setup an experiment to detect a magnetic field due to the Lorentz force acting on a current. It is a hollow conducting cylinder with a magnet at one end. With current flowing in the cylinder I approach the negative end with the north pole of the magnet. Using the left hand rule I expected the...
  7. M

    How Do Lorentz Group Commutation Relations Apply to Spin Matrices?

    Homework Statement Prove that the sets ##(S_{\mu\nu})_L## and ##(S_{kl})_R##, where $$ \left( S _ { k \ell } \right) _ { L } = \frac { 1 } { 2 } \varepsilon _ { j k \ell } \sigma _ { j } = \left( S _ { k \ell } \right) _ { R } \quad\text{and}\quad \left( S _ { 0 k } \right) _ { L } = \frac {...
  8. N

    B Trying to understand Lorentz Transformations

    I am trying to understand the general form of the Lorentz Transformations before I even get into the long process of deriving that into the specific equations. In Taylor and Wheeler's, Spacetime Physics book they give this as the general form: t= Bx1 + Dt1 x= Gx1 + Ht1 In the equation for t...
  9. H

    I Confusion about the quantum field Lorentz transformation

    On page 59 of Peskin & Schroeder, there's a section on the lorentz transformation of field operators which I've attached. I'm confused about the part towards the end where he does a change of variable on the integration measure; it seems like he's only rewriting the lorentz-invariant integration...
  10. A

    Is the Lorentz magnetic force verified?

    Can someone provide me with some original experiments conducted which verified the Lorentz magnetic force : F = q(v X B). Google does not give me any links except to explanations of the Lorentz force law.
  11. wafelosek

    A Killing vectors corresponding to the Lorentz transformations

    Hi everyone! I have a problem with one thing. Let's consider the Lorentz group and the vicinity of the unit matrix. For each ##\hat{L}## from such vicinity one can prove that there exists only one matrix ##\hat{\epsilon}## such that ##\hat{L}=exp[\hat{\epsilon}]##. If we take ##\epsilon^{μν}##...
  12. K

    I Is this answer about Lorentz transforms correct?

    User Jack Fraser says that both ##X## and ##\Lambda## on his post are tensors. Is this right? Post: https://www.quora.com/While-deriving-the-Lorentz-transformation-how-do-you-know-that-the-transformation-will-be-linear
  13. M

    Prove that these terms are Lorentz invariant

    Homework Statement Prove that $$\begin{align*}\mathfrak{T}_L(x) &= \frac{1}{2}\psi_L^\dagger (x)\sigma^\mu i\partial_\mu\psi_L(x) - \frac{1}{2}i\partial_\mu \psi_L^\dagger (x) \sigma^\mu\psi_L(x) \\ \mathfrak{T}_R(x) &= \frac{1}{2}\psi_R^\dagger (x)\bar{\sigma}^\mu i\partial_\mu\psi_R(x) -...
  14. B

    I Can the Lorentz factor be modified for non-inertial frames?

    The term "Lorentz transformations" only refers to transformations between inertial frames. However, if we differentiate velocity with respect to time, we obtain acceleration. The Lorentz factor says: t(0 reference frame observer at rest) / t(moving) = 1 / Sqrt[1–(v/c)^2] t0 / tm =...
  15. A

    I Why Do Lorentz Transforms Look Like This?

    We have all seen Lorentz transformations being written like this ##\Lambda ^\mu\;_\nu##, but why are they never written as ##\Lambda _\nu\;^\mu##?
  16. H

    A Derivation of the Noether current - Lorentz Transformation

    We make an infinitesimal Lorentz transformation of the Lagrangian and require it to be invariant. We then arrive at the following expression. $$\epsilon^{\mu\nu}j_{\mu\nu} = P_{\mu}\epsilon^{\mu\nu}X_{\nu}$$ which can be written as $$\epsilon^{\mu\nu}j_{\mu\nu} =...
  17. T

    I Lorentz Transformation in One-Dimensional Space

    If space only had one dimension would Einstein's speed of light postulate still lead to Lorentz transformation for motion along that one dimension? Relativity of simultaneity can obviously be demonstrated in one dimension (lightning bolts hitting opposite ends of stationary and moving train)...
  18. J

    B Is the Lorentz transformation about observers?

    From a previous, now closed thread (Perok): "Technically, the Lorentz Transformation is not about observers but about reference frames." Sorry, I still don't get this. In frame A with observer A at the origin, x is the distance of the event X he sees measured on his rod, i.e. as...
  19. J

    B Learning Lorentz Derivation: Solving x=vt+γx' vs. x=vt+x'/γ

    From a previous thread, Nugatory: "If the answers already supplied are not enough for the original poster to work out for themself why x=vt+x'/γ, and not x=vt+γx′, is the correct expression, we can have another thread devoted to only that question." Here it is. Either Wiki is wrong or I am. In...
  20. Sorcerer

    I Lorentz Transform of E and B: Considerations by DJ Juggernaut

    Obviously in the title I mention the user that recently got banned, but the reason I do is because s/he was having some trouble accepting that a B field transforms into a mixture of E and B fields per the Lorentz transformation (and other assorted quackery), so it got me thinking about why this...
  21. J

    B Basic Lorentz transformation derivation

    The Lorentz transformations are mathematically simple. I had always imagined they could be easily derived. I however just found out from another PF thread that this is not so. Their originators Lorentz and Poincaré simply stated them without derivation. And the "proofs" I have seen to date have...
  22. tomdodd4598

    I Exploring Direct Sums of Lorentz Group Representations

    Hey there, I've suddenly found myself trying to learn about the Lorentz group and its representations, or really the representations of its double-cover. I have now got to the stage where the 'complexified' Lie algebra is being explored, linear combinations of the generators of the rotations...
  23. snoopies622

    B Lorentz Invariant Paths in Spacetime

    Last night I was pleasantly surprised to discover that, given a particle trajectory x^2 - c^2t^2 = a^2 when viewed through a Lorentz transformation x' = \gamma (x-vt) t' = \gamma (t - vx/c^2) produces exactly the same shape x'^2 - c^2t'^2 = a^2 . I suppose this is equivalent to the...
  24. gasar8

    Canonical invariance vs. Lorentz invariance

    Homework Statement I have an assignment to prove that specific intensity over frequency cubed is Lorentz invariant. One of the main tasks there is to prove the invariance of phase space d^3q \ d^3p and I am trying to prove it with symplectic geometry. I am following Jorge V. Jose and Eugene J...
  25. gasar8

    A Lorentz Invariant Phase Space: Symplectic Geometry

    I have an assignment to show that specific intensity over frequency cubed \frac{I}{\nu^3}, is Lorentz invariant and one of the main topics there is to show that the phase space is Lorentz invariant. I did it by following J. Goodman paper, but my professor wants me to show this in another way...
  26. Arman777

    What is the velocity of observer O' in the Lorentz Transformation problem?

    Homework Statement According to observer ##O##, a blue flash occurs at ##x_b =10.4m## when ##t_b =0.124 μs##, and a red flash occurs at ##x_r =23.6m## when ##t_r =0.138 μs##. According to observer ##O'##, who is in motion relative to ##O## at velocity ##u##, the two flashes appear to be...
  27. D

    A Lorentz invariance from Dirac spinor

    I have a really naive question that I didn't manage to explain to myself. If I consider SUSY theory without R-parity conservation there exist an operator that mediates proton decay. This operator is $$u^c d^c \tilde d^c $$ where ##\tilde d## is the scalar superpartner of down quark. Now...
  28. J

    A Hardy's Paradox and lorentz invariant realist interpretation

    Does Hardy's paradox show that all realist interpretations cannot be made lorentz invariant? Or is it just realist hidden variable theories?
  29. Celso

    Nullifying Lorentz Force on Proton Moving in Parallel Direction

    Homework Statement A proton moves with a speed ##v = 3 \cdot 10^5 \frac{m}{s}## in the parallel direction to ##i+k##. A magnetic field of ##1T##, in the ##i+j+k## acts over it. Which electric field must we apply in this region so that the Lorentz force over the proton is null? Homework...
  30. zox00

    I Deriving Lorentz from time dilation and length contraction

    Is it possible to derive the Lorentz transformation from time dilation and length contraction? If so, how should I start? I know how to derive it while considering 4 scenarios finding values of A, B,D,E in x'=Ax+Bt t'=Dx+Et and the transformation is: x'=(x-vt)/sqrt(1-v^2/c^2)...
  31. D

    I Lorentz Transformation: Explaining Invariance of c?

    Please tell me if Lorentz Transformation would be altered in any way if the invariance of c is explained, instead of postulated.
  32. K

    Vector representation of Lorentz group

    Homework Statement In this problem, we'll construct the ##(\frac{1}{2},\frac{1}{2})## representation which acts on "bi-spinors" ##V_{\alpha\dot{\alpha}}## with ##\alpha=1,2## and ##\dot{\alpha}=1,2##. It is convential, and convenient, to define these bi-spinors so that the first index...
  33. G

    B Prove Lorentz Factor w/o Speed of Light

    The Lorentz factor shows how fast one frame will judge speeds in another frame to be taking into account the relative motion between the two frames. The speed of light is a factor in the Lorentz factor but I have heard that this is not because the speed of light is fundamental to it. So...
  34. Sorcerer

    I Easiest possible way to derive the Lorentz transformation

    I put the level for this thread as I, but anything from B to A is acceptable here. I'm hoping this isn't too imprecise, but what are the easiest or simplest (or fastest) ways to derive the Lorentz transformation equations you know? I am not after blatant corner cutting here, by the way. Just...
  35. CharlieCW

    General Irreducible Representation of Lorentz Group

    This one may seem a bit long but essentially the problem reduces to some matrix calculations. You may skip the background if you're familiar with Lorentz representations. 1. Homework Statement A Lorentz transformation can be represented by the matrix...
  36. Kaguro

    I Solving Lorentz Contraction Question: What went Wrong?

    Hello all. I am having some small trouble with applying the lorentz transformations to calculate lorentz contraction. Here's what I did: Let O be the rest system and O' be the system moving with velocity v w.r.t O along x axis. Consider a rod lying in the O' system with ends x1' and x2'...
  37. Arman777

    I Deriving Lorentz Transformation

    How can we derive Lorentz Transformation ? I used one approach using the length contraction and time dilation and simultaneity but my prof wasnt much happy about it. Is there any other way to derive it ?
  38. Milsomonk

    I Lorentz Symmetry at Black Hole Event Horizon

    Hello people, I have been thinking about a concept that I was taught whilst learning GR, If I understand correctly it is that Lorentz symmetry becomes local when we consider GR. This makes sense to me as then the metric is generally speaking not Minkowski, only for a...
  39. Arman777

    Deriving Lorentz Transformation

    Homework Statement How can we derive Lorentz Transformation using the length contraction and time dilation equations of relativity ? Homework Equations ##γ = 1/ (\sqrt{1-u^2/c^2})## ##t = t_0γ## ##L = L_0/γ## The Attempt at a Solution [/B] In position Lorentz Transformation calculations...
  40. J

    A Are Modal interpretations emprically Lorentz invariant?

    Modal interpretations are a class of realist non local hidden variable theories. However, they cannot be made fundamentally lorentz invariant. However, neither can bohmian mechanics but BH is still emprically lorentz invariant. So are modal interpretation empirically lorentz invariant as well?
  41. E

    I Lorentz invariance and equation of motion for a scalar field

    Hi there, I just saw some lectures where they claim that the Klein Gordon equation is the lowest order equation which is Lorentz invariant for a scalar field. But I could easily come up with a Lorentz invariant equation that is first order, e.g. $$ (M^\mu\partial_\mu + m^2)\phi=0 $$ where M is...
  42. D

    I Index placement -- Lorentz transformation matrix

    Hi. I came across the following statement , which seems wrong to me. Λμρ = ( ΛT )ρμ I have it on good authority (a previous post on this forum) that (ΛT)μν = Λνμ so I am hoping that the first equation is wrong ? It looks like the inverse not the transpose ? The equation Λμρ η μνΛνσ = ηρσ is...
  43. F

    Show that a matrix is a Lorentz transformation

    Homework Statement Given the matrix $$ \Omega = \begin{pmatrix} 0 & -\psi & 0 & 0 \\ -\psi & 0 & 0 & 0 \\ 0 & 0 & 0 & 0 \\ 0 & 0 & 0 & 0 \end{pmatrix}$$ show that ## e^{\Omega}## is a Lorentz transformation along the x-axis with ## \beta = tanh(\psi)## Homework Equations During the lesson we...
  44. I

    I Does the Invariance of Proper Time Lead to the Lorentz Transformation?

    Hi, I've seen several explanations for sr on youtube. But they all start off explaining from a different perspective. I was wondering how the fundamental postulates of sr lead to the invariance of proper time between frames, and also what "order" everything is derived in. For example, does the...
  45. S

    B Calculating Lorentz Factor with V=0

    How do I calculate the Lorentz factor with v=0. Or do I not calculate it since it can be said that the observer is in the same frame of reference?
  46. T

    I Understanding Lorentz Transform Outputs

    Good afternoon, Not sure if this should be in the homework section or not but in any case... I'm having difficulty understanding the outputs from the Lorentz transform. Example problem. The Earth and sun are 8.3 light-minutes apart. Ignore their relative motion for this problem and assume...
  47. T

    Magnetic Lorentz Force: Questions & Answers

    Magnetic Lorentz force is the force experienced by any charged particle moving in a magnetic field.i want to clarify some doubts regarding this topic of Magnetic Lorentz force.some of them are: 1. Is it the Lorentz force that is actually responsible for the phenomenon of electromagnetic...
  48. DatLemonDoe

    B Deriving Lorentz Factor: An Analysis of Jimmy360's Method

    Hello! This is my first post on this forum, so make sure to tell me if I am doing something wrong :) I was trying to derive the Lorentz factor today, and I used the following page as a guide. The top answer by Jimmy360 is what I followed...
  49. P

    I Index notation for inverse Lorentz transform

    Hi all, just had a question about tensor/matrix notation with the inverse Lorentz transform. The topic was covered well here, but I’m still having trouble relating this with an equation in Schutz Intro to GR... So I can use the following to get an equation for the inverse...
  50. Chris Miller

    B Can the Lorentz Factor Approach 0i as v Exceeds c for FTL Reference Frames?

    As v approaches c, the Lorentz factor approaches infinity. The math and physics is well understood and observed. Is it true that, just mathematically, as v exceeds c the Lorentz factor approaches 0i for imaginary time constriction?
Back
Top