Relativistic quantum mechanics

Quantum mechanics taking into account particles near or at the speed of light

In physics, relativistic quantum mechanics (RQM) is any Poincaré-covariant formulation of quantum mechanics (QM). This theory is applicable to massive particles propagating at all velocities up to those comparable to the speed of light c, and can accommodate massless particles. The theory has application in high-energy physics, particle physics and accelerator physics, as well as atomic physics, chemistry and condensed matter physics.

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