Lorentz transform Definition and 58 Threads

  1. cianfa72

    I Inertial reference frame and Bondi k-calculus

    Hi, I was reading the Bondi k-calculus as introduced in R. d'Inverno book and Bondi k-calculus. As far as I understand, in the context of SR, the radar time coordinate from an inertial observer/clock is basically the same as the coordinate time ##t## assigned to any event from an inertial frame...
  2. Physicsperson123

    I Why Do Some Events in My Lorentz Transformation Appear Incorrect?

    Here is the space-time diagram of an observer: Here is the diagram as seen by an observer travelling from left to right: I have attempted to represent the axis system of the moving observer on the axis system of the stationary observer in the following diagram: Event D seems to lie in...
  3. R

    Galilean transform and Lorentz transform questions

    I have a quick question about the Galilean transform. If I have Alice running and Bob stationary. The Galilean transform will tell me the position of Alice from Bob's stationary position. Also if I have Alice's position which is moving it will tell me Bob's stationary position. If I want Bob...
  4. B

    Question about the Lorentz transform

    Image below. Is the Lorentz transform just switching between a stationary frame and a moving frame? I forgot to write Alice's frame but I assume that is obvious.
  5. thaiqi

    I Lorentz Transform Deduction: Question Explained

    I read in one book about the deduction of Lorentz transform. It writes: ' $$ \begin{aligned} t^\prime & = \xi t + \zeta x (1) \\ x^\prime & = \gamma x + \delta t (2) \\ y^\prime & = y (3) \\ z^\prime & = z (4) \end{aligned} $$ from (2), it gives: $$ \begin{aligned} {dx \over dt} = -{ \delta...
  6. T

    Invariance of the Lorentz transform

    of course y and z terms are invariant but for the x and t terms I am getting an additional factor of 1/1-v^2/c^2
  7. 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...
  8. 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...
  9. 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...
  10. D

    Relativity With velocity of objects moving in different fram

    Homework Statement i)A police spaceship P is chasing another spaceship A. Both ships have velocities βP = βA = 3c/5 as measured along the x-axis in the Solar System reference frame O. The police ship is a distance L = 1 light-second (i.e. the distance traveled by light in one second) behind...
  11. D

    I Transpose and Inverse of Lorentz Transform Matrix

    Let ##\Lambda## be a Lorentz transformation. The matrix representing the Lorentz transformation is written as ##\Lambda^\mu{}_\nu##, the first index referring to the rows and the second index referring to columns. The defining relation (necessary and sufficient) for Lorentz transforms is...
  12. B

    A Spinor Lorentz Transform via Vectors - Cross Product Issue

    The Lorentz transformation operator acting on an undotted, i.e. right-handed, spinor can be expressed as $$e^{-\frac{1}{2} \sigma \cdot \mathbf{\phi} + i\frac{1}{2} \sigma \cdot \mathbf{\theta}}.$$ There is a very cool, almost childlike, derivation of this expression in Landau Vol. 4 S. 18 I've...
  13. Jonathan Densil

    B Using Lorentz Transformations vs Time Dilation/Length Contraction

    Hey guys, In what circumstance or scenario would you use Lorentz transformations as a opposed to time dilation or length contraction? The reason that I ask this is because in all of the problems that I have worked with, the observer is always stationary relative to the event. For example, if...
  14. G

    Imaginary Transverse Space of Superluminal Lorentz Transform

    I was reading this paper: http://dinamico2.unibg.it/recami/erasmo%20docs/SomeOld/RevisitingSLTsLNC1982.pdf It is on superluminal Lorentz transformations and is too advanced for me. :confused: But anyway, take a look at equation(s) (11). For the y' and z' transformations, there is an imaginary...
  15. Erland

    Assuming Lorentz transform is affine

    Alonso has in fact raised a relevant issue. Given any clock synchronization in the embankment frame, there is a unique pair of points at the embankment with coordinates x=a and x=b, and a unique time t=T, such that at t=T in the embankment frame, these points are next to the back end and the...
  16. B

    Can you use the Lorentz transform for a function of time?

    Reading Griffiths, he states that the Lorentz Transform is useful for describing where an 'event' occurs in a different inertial frame. What about describing the motion of a particle in this moving frame if I know its motion in my frame? Really, I'm looking at pickup ions in the solar wind. A...
  17. D

    Lorentz scalars - transformation of a scalar field

    When one considers a Lorentz transformation between two frames ##S## and ##S'##, such that the coordinates in ##S## are given by ##x^{\mu}## and the coordinates in ##S'## are given by ##x'^{\mu}##, with the two related by x'^{\mu}=\Lambda^{\mu}_{\;\;\nu}x^{\nu} then a scalar field ##\phi (x)##...
  18. D

    Consequences of space-/time-/light-like separations

    I'm trying to prove the following statements relating to space-like, time-like and light-like space-time intervals: 1. There exists a reference frame in which two space-time events are simultaneous if and only if the two events are space-like separated. 2. There exists a reference frame in...
  19. E

    Relative Velocity in Lorentz Transform: Agree or Disagree?

    Do two inertial observers in relative motion agree on their relative velocity? Velocity is distance per unit time and they don’t agree on the distance or the elapsed time. If the apparent distance in the prime system is shorter and the elapsed time is longer, then it seems that the apparent...
  20. abrogard

    How To Understand This Lorentz Transform?

    Prof Ramamurti Shankar has this Youtube video 'Introduction to Relativity' at And in it he derives the Lorentz Transforms something like this, at about 58 minutes into it. |------------------------- t ----------------------| time |-----ut---------------|---------- x' -------------|...
  21. D

    Understand Relativity & Lorentz Transformation - Aaron

    Hi all,I am trying to understand relativity and Lorentz Transformation more clearly but I have some problems. Assume that we have frame F' which is moving at velocity v with respect to F. Now assume we have an object, O, moving at velocity, w, with respect to F. Frame F has its own time, t, and...
  22. B

    Lorentz Transform on Covariant Vector (Lahiri QFT 1.5)

    Homework Statement Given that ##x_\mu x^\mu = y_\mu y^\mu## under a Lorentz transform (##x^\mu \rightarrow y^\mu##, ##x_\mu \rightarrow y_\mu##), and that ##x^\mu \rightarrow y^\mu = \Lambda^\mu{}_\nu x^\nu##, show that ##x_\mu \rightarrow y_\mu = \Lambda_\mu{}^\nu x_\nu##. Homework Equations...
  23. T

    Solving Lorentz Transform problem using only length contraction

    Homework Statement A traveler in a rocket of length 2d sets up a coordinate system S' with origin O' anchored at the exact middle of the rocket and the x' axis along the rocket’s length. At t' = 0 she ignites a flashbulb at O'. (a) Write down the coordinates t'_F, x'_F, and t'_B, x'_B for...
  24. A

    Determination of Lorentz transform from euclid geometry

    A first stage of the determination. We have a body of length L = AB, which moves along the x-axis with velocity v, say that coming to us. A -------- B v <--- | | h - vertical distance | ./ - a light converges to us with the speed eq. c | / O ---------> x At some time t = 0, we see the point A...
  25. matt_crouch

    Lorentz Transform of Radial & Longitudinal Dependent Magnetic Field

    Basically I am trying to lorentz transform the magnetic field along θ of a bunch particles which have a gaussian distribution to the radial electric field. However the magnetic field in θ is dependent on the longitiudinal distribution. Now initially i thought we would just use the standard LT...
  26. P

    Detailed working out Lorentz contraction from the Lorentz transform

    We have a few posters struggling with this, I thought I'd post a step by step guide, to see if it would help. That seems easier than trying to untangle the confused threads we have. We'll see if it works... Setup and notation: We have a rocket, which has a front and a back. We have a...
  27. fluidistic

    Infinitesimal Lorentz transform and its inverse, tensors

    Homework Statement The problem can be found in Jackson's book. An infinitesimal Lorentz transform and its inverse can be written under the form ##x^{'\alpha}=(\eta ^{\alpha \beta}+\epsilon ^{\alpha \beta})x_{\beta}## and ##x^\alpha = (\eta ^{\alpha \beta}+\epsilon ^{'\alpha \beta})...
  28. fluidistic

    Wave equation invariance under Lorentz transform

    Homework Statement I must show that the one dimensional wave equation ##\frac{1}{c^2} \frac{\partial u}{\partial t^2}-\frac{\partial ^2 u}{\partial x^2}=0## is invariant under the Lorentz transformation ##t'=\gamma \left ( t-\frac{xv}{c^2} \right )## , ##x'=\gamma (x-vt)##Homework Equations...
  29. G

    Lorentz transform low velocity limit

    Why do we say that t'=t for Galilean transformation, when the low velocity limit of the Lorentz transformation is t'=t+vx/c2? If x is really big, then doesn't time cease to be absolute, no matter how small v/c is?
  30. thrush

    Confusion about Lorentz Transform

    Hi! I am new here, thought to join as I am trying to learn Relativity, in this case Special Relativity. I have solved a bunch of problems already but ... The Lorentz Transform formulation I am dealing with is a 4x4 matrix. I understand the invariance of the spacetime interval and have...
  31. G

    Derive lorentz transform for energy

    Homework Statement Derive the relation: E' = \gamma (E + \beta p c)Homework Equations p' = \gamma p \\ E^{2} = p^{2} c^{2} + M^{2}c^{4}The Attempt at a Solution start off with stationary frame S E=mc^{2} then in moving frame S' E'^{2} = p'^{2} c^{2} + E^{2}: lorent transform momentum: E'^{2} =...
  32. Dale

    Basic Lorentz Transform widget

    I have recently found that Mathematica has a "reader" which allows interactive calculations and plots to be shared. Here is a simple example, please let me know if there is interest in more such widgets.
  33. F

    Applying Lorentz transform to current 4 vector

    Homework Statement Consider an infinite line of charge with density λ per unit length lying along the z-axis. If the line of charge is stationary in frame S, use the Lorentz transform to find the current and charge densities in a frame S' which is moving with velocity v parallel to the...
  34. S

    How to get time dilation & length contraction from Lorentz transform?

    OK, I've found a great explanation of the derivation of the Lorentz transformation, with x' = γ [ x - v t ] t' = γ [ t - ( v / c2 ) x ] so if I take the other term as 0, there is x'( t = 0 ) = γ x t'( x = 0 ) = γ t but the problem is that the time dilation & length...
  35. G

    Lorentz transform of a scalar in QM

    If you Lorentz transform a scalar: U^{-1}(\Lambda)\phi(x)U(\Lambda)=\phi(\Lambda^{-1}x) If you now perform another Lorentz transform, would it it look like this: U^{-1}(\Lambda')U^{-1}(\Lambda)\phi(x)U(\Lambda)U(\Lambda')=\phi(\Lambda'^{-1}\Lambda^{-1}x) ? But isn't this wrong...
  36. 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...
  37. B

    What Is psi_PRIME in the Lorentz Transform of a Wavepacket?

    Homework Statement see attached .pdf. all parts of problem statement are italicized. Homework Equations see attached .pdf The Attempt at a Solution see attached .pdf Actually: my question is pretty qualitative. You can look at everything I've done with this problem so far...
  38. D

    Deriving Length Contraction From Lorentz Transform

    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...
  39. K

    Easy Lorentz Transform Problem

    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...
  40. maverick_starstrider

    Derivation of space-time interval WITHOUT Lorentz transform?

    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...
  41. B

    Lorentz transform on the Dirac equation

    Homework Statement Show that a Lorentz transformation preserves the sign of the energy of a solution to the Dirac equation. The Attempt at a Solution I'm not sure how to approach this. So I apply the Lorentz transform to the Dirac equation, and work through it to obtain the energy...
  42. A

    When and where is the signal received according to different reference frames?

    Homework Statement A spaceship of proper length Lp = 400 m moves past a transmitting station at a speed of v = 0.76c. At the instant that the nose of the spaceship passes the transmitter, clocks at the transmitter and in the nose of the spaceship are synchronized to t = t' = 0. The instant...
  43. K

    Derivation of Dirac equation using Lorentz transform

    Hi..I was studying Ryder, Chapter 2[Quantum Field Theory]...he derives the Dirac eq using Lorentz transformations..I found the approach fascinating..but there is one part I do not really understand... Just a few lines before he writes down the Dirac equation, he identifies \varphi_{R}(0) with...
  44. I

    S,S' in the Lorentz transform.

    When we use the Lorentz transform. We must have S,S' frame. How can we choose S,S' frame?
  45. I

    How to Derive the Lorentz Transformation for the x Component of Momentum?

    Homework Statement Derive the Lorentz transformation for the x component of momentum, i.e. Px' = \gamma (Px - vE/(c^{}2)) I've used Px = x component of momentum (not very good with latex, sorry!) Homework Equations I thought the best place to start was the Lorentz transformation...
  46. E

    Which Nova Happened First in Relation to an Aircraft's Speed?

    Homework Statement Astronomers on the Earth (regarded as an inertial reference frame) see two novas flare up simultaneously. One of the novas is at a distance of 1.0x10^3 lightyears in the constelation Draco; the other nova is at an equal distance in the constellation Tucana in a direction (as...
  47. M

    Exploring the Validity of Lorentz Transform and Discrete Space-Time Models

    If we impose that under no force or gravitational field Lorentz transform must hold, my question is if the validity of Lorentz transform means that space time must be continous, or on the other hand if there may be a discrete model of space-time that preserves Lorentz transform. For example...
  48. A

    Lorentz Transform in Non-Minkowski Spaces

    What is the equivalent of the Lorentz Transform when the metric is not Minkowski? How do you do a coordinate transform with a metric that has non-diagonal terms?
  49. G

    Lorentz Transform Homework: Particle Motion Toward Origin

    Homework Statement Suppose that a particle of mass m and energy E is moving toward the origin of a system S such that its velocity u makes an angle alpha with the y-axis (approaches origin from upper right). Using the Lorentz transformations for energy and momentum, determine the energy E' of...
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