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Four-vectors
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Combined spacetime vectors invariant under boosts.
Four-component vectors (ct, x, y, z), (E/c, p) whose lengths are invariant under Lorentz transformations. They make relativistic equations covariant.
The four-momentum norm gives the mass.
Used in particle physics.
In more detail
Four-vectors combine time and space components, such as the four-momentum (E/c, p). They transform as a unit under Lorentz transformations, which simplifies relativistic calculations.
Real-world uses
- Four-vectors are used throughout particle physics.
- They provide compact notation for relativistic equations.
- Physicists write relativistic equations in four-vector form so that they look the same in all inertial frames.
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Frequently asked questions
What is the four-momentum?
The vector of energy divided by c, and the three-momentum.
Why are they useful?
They keep equations covariant, meaning they have the same form in all frames.
What is a four-vector?
A set of four components, including time and space, that transforms in a consistent way between frames.
Related topics in Relativity
Massless particles · Relativistic Doppler effect · Aberration of light · Relativistic collisions · Particle accelerators and relativity · Mass–energy in nuclear reactions