What is Energy-momentum: Definition and 103 Discussions

In physics, the energy–momentum relation, or relativistic dispersion relation, is the relativistic equation relating total energy (which is also called relativistic energy) to invariant mass (which is also called rest mass) and momentum. It is the extension of mass–energy equivalence for bodies or systems with non-zero momentum. It can be written as the following equation:

This equation holds for a body or system, such as one or more particles, with total energy E, invariant mass m0, and momentum of magnitude p; the constant c is the speed of light. It assumes the special relativity case of flat spacetime. Total energy is the sum of rest energy and kinetic energy, while invariant mass is mass measured in a center-of-momentum frame.
For bodies or systems with zero momentum, it simplifies to the mass–energy equation



E
=

m

0



c

2




{\displaystyle E=m_{0}c^{2}}
, where total energy in this case is equal to rest energy (also written as E0).
The Dirac sea model, which was used to predict the existence of antimatter, is closely related to the energy–momentum relation.

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  1. H

    A Derivation of energy-momentum tensor in "QFT and the SM" by Schwartz

    My question is about this step in the derivation: When the ##\partial_\nu \mathcal L## in 3.33 moves under the ##\partial_\mu## in 3.34 and gets contracted, I'd expect it to become ##\delta_{\mu \nu} \mathcal L##. Why is it rather ##g_{\mu \nu} \mathcal L## in the 3.34? (In this text, ##g_{\mu...
  2. alan123hk

    B Algebraic Operations on Energy-Momentum Relationships

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  3. C

    B Robert Wald's General Relativity: Energy-Momentum Relation

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  4. C

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  5. Ranku

    I Energy-momentum tensor as energy density

    Can the energy-momentum tensor of matter and energy be cast in terms of energy density of matter and energy, similar to how the energy-momentum tensor of vacuum energy can be cast in terms of the energy density of vacuum energy?
  6. F

    Energy-momentum tensor for a relativistic system of particles

    I think it is quite simple as an exercise, following the two relevant equations, but at the beginning I find myself stuck in going to identify the lagrangian for a relativistic system of non-interacting particles. For a free relativistic particle I know that lagrangian is...
  7. Diracobama2181

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  8. Pouramat

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  9. B

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  10. Diracobama2181

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  11. MattGeo

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  12. JD_PM

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  13. S

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  14. George Keeling

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  15. M

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  16. K

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  17. sergiokapone

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  18. T

    I Looking for more accurate energy-momentum transformations for photons

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  19. A

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  20. G

    I Is energy-momentum invariant and/or conserved?

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  21. G

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  22. P

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  23. K

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  24. binbagsss

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  25. e2m2a

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  26. S

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  27. A

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  28. davidge

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  29. A

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  30. D

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  31. haushofer

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  32. M

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  33. F

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  34. S

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  35. S

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  36. T

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  37. Alain De Vos

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  38. U

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  39. D

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  40. bcrowell

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  41. G

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  42. binbagsss

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  43. U

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  44. D

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  45. R

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  46. F

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  47. S

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  48. L

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  49. Spinnor

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  50. WannabeNewton

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