Search results
Results from the WOW.Com Content Network
The energy and momentum of an object measured in two inertial frames in energy–momentum space – the yellow frame measures E and p while the blue frame measures E ′ and p ′. The green arrow is the four-momentum P of an object with length proportional to its rest mass m 0.
The stress–energy tensor, sometimes called the stress–energy–momentum tensor or the energy–momentum tensor, is a tensor physical quantity that describes the density and flux of energy and momentum in spacetime, generalizing the stress tensor of Newtonian physics. It is an attribute of matter, radiation, and non-gravitational force fields.
The Abraham–Minkowski controversy is a physics debate concerning electromagnetic momentum within dielectric media. [1] [2] Two equations were first suggested by Hermann Minkowski (1908) [3] and Max Abraham (1909) [4] [5] for this momentum. They predict different values, from which the name of the controversy derives. [6]
The stress–energy tensor of a relativistic pressureless fluid can be written in the simple form T μ ν = ρ 0 U μ U ν . {\displaystyle T^{\mu \nu }=\rho _{0}U^{\mu }U^{\nu }.} Here, the world lines of the dust particles are the integral curves of the four-velocity U μ {\displaystyle U^{\mu }} and the matter density in dust's rest frame is ...
If the energy–momentum tensor T μν is zero in the region under consideration, then the field equations are also referred to as the vacuum field equations. By setting T μν = 0 in the trace-reversed field equations , the vacuum field equations, also known as 'Einstein vacuum equations' (EVE), can be written as R μ ν = 0 . {\displaystyle R ...
The element of the stress–energy tensor represents the flux of the component with index of the four-momentum of the electromagnetic field, , going through a hyperplane. It represents the contribution of electromagnetism to the source of the gravitational field (curvature of spacetime) in general relativity .
With respect to classical physics, conservation laws include conservation of energy, mass (or matter), linear momentum, angular momentum, and electric charge. With respect to particle physics, particles cannot be created or destroyed except in pairs, where one is ordinary and the other is an antiparticle.
In such universes Mach's principle can be stated as the distribution of matter and field energy-momentum (and possibly other information) at a particular moment in the universe determines the inertial frame at each point in the universe (where "a particular moment in the universe" refers to a chosen Cauchy surface). [7]: 188–207