Simplifying assumptions about the behavior of the stress–energy tensor in general relativity
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In relativistic classical field theories of gravitation, particularly general relativity, an energy condition is a generalization of the statement "the energy density of a region of space cannot be negative" in a relativistically phrased mathematical formulation. There are multiple possible alternative ways to express such a condition such that can be applied to the matter content of the theory. The hope is then that any reasonable matter theory will satisfy this condition or at least will preserve the condition if it is satisfied by the starting conditions.
Energy conditions are not physical constraints per se, but are rather mathematically imposed boundary conditions that attempt to capture a belief that "energy should be positive".[1] Many energy conditions are known to not correspond to physical reality—for example, the observable effects of dark energy are well known to violate the strong energy condition.[2][3]
In general relativity, energy conditions are often used (and required) in proofs of various important theorems about black holes, such as the no hair theorem or the laws of black hole thermodynamics.
^Curiel, E. (2014). "A Primer on Energy Conditions". arXiv:1405.0403.
^Farnes, J.S. (2018). "A Unifying Theory of Dark Energy and Dark Matter: Negative Masses and Matter Creation within a Modified ΛCDM Framework". Astronomy & Astrophysics. 620: A92. arXiv:1712.07962. Bibcode:2018A&A...620A..92F. doi:10.1051/0004-6361/201832898. S2CID 53600834.
^Visser, Matt; Barceló, Carlos (2000). "Energy Conditions and Their Cosmological Implications". Cosmo-99. pp. 98–112. arXiv:gr-qc/0001099. doi:10.1142/9789812792129_0014. ISBN 978-981-02-4456-9. S2CID 119446302.
gravitation, particularly general relativity, an energycondition is a generalization of the statement "the energy density of a region of space cannot be negative"...
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of the averaged null energycondition. Quantum effects such as the Casimir effect cannot violate the averaged null energycondition in any neighborhood...
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various energy conditions, such as the null energycondition along with the weak, strong, and dominant energy conditions. However, it is known that quantum...
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quantum states that violate the averaged null energycondition (i.e. have negative renormalized energy spread over a sufficiently large region). This...
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concept is named after Augustin-Louis Cauchy. Under the averaged weak energycondition (AWEC), Cauchy horizons are inherently unstable. However, cases of...
possible. In particular, he assumed that all matter satisfies the weak energycondition. Oldham, L. J.; Auger, M. W. (March 2016). "Galaxy structure from multiple...
The word energy derives from Greek ἐνέργεια (energeia), which appears for the first time[when?] in the 4th century BCE works of Aristotle (OUP V, 240,...
spacetime. The condition of (M, g) having nonnegative scalar curvature is equivalent to the spacetime obeying the dominant energycondition. This inequality...
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electronics, condition monitoring, and wireless sensor networks. Energy harvesters usually provide a very small amount of power for low-energy electronics...
illumination, heating and air conditioning, and communication, for industrial, commercial, and domestic purposes. Energy resources may be classified as...
length. Chemical energy – energy contained in molecules Electrical energy – energy from electric fields Electro-centric energy – energy sustaining the continuous...
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