enow.com Web Search

Search results

  1. Results from the WOW.Com Content Network
  2. Lambdavacuum solution - Wikipedia

    en.wikipedia.org/wiki/Lambdavacuum_solution

    In general relativity, a lambdavacuum solution is an exact solution to the Einstein field equation in which the only term in the stress–energy tensor is a cosmological constant term. This can be interpreted physically as a kind of classical approximation to a nonzero vacuum energy .

  3. Vacuum - Wikipedia

    en.wikipedia.org/wiki/Vacuum

    As a result, QED vacuum contains vacuum fluctuations (virtual particles that hop into and out of existence), and a finite energy called vacuum energy. Vacuum fluctuations are an essential and ubiquitous part of quantum field theory. Some experimentally verified effects of vacuum fluctuations include spontaneous emission and the Lamb shift. [15]

  4. Negative energy - Wikipedia

    en.wikipedia.org/wiki/Negative_energy

    The negative-energy particle then crosses the event horizon into the black hole, with the law of conservation of energy requiring that an equal amount of positive energy should escape. In the Penrose process , a body divides in two, with one half gaining negative energy and falling in, while the other half gains an equal amount of positive ...

  5. Zero-point energy - Wikipedia

    en.wikipedia.org/wiki/Zero-point_energy

    A vacuum can be viewed not as empty space but as the combination of all zero-point fields. In quantum field theory this combination of fields is called the vacuum state, its associated zero-point energy is called the vacuum energy and the average energy value is called the vacuum expectation value (VEV) also called its condensate.

  6. Cosmological constant problem - Wikipedia

    en.wikipedia.org/wiki/Cosmological_constant_problem

    The calculated vacuum energy is a positive, rather than negative, contribution to the cosmological constant because the existing vacuum has negative quantum-mechanical pressure, while in general relativity, the gravitational effect of negative pressure is a kind of repulsion.

  7. Vacuum energy - Wikipedia

    en.wikipedia.org/wiki/Vacuum_energy

    The field strength of vacuum energy is a concept proposed in a theoretical study that explores the nature of the vacuum and its relationship to gravitational interactions. The study derived a mathematical framework that uses the field strength of vacuum energy as an indicator of the bulk (spacetime) resistance to localized curvature.

  8. Casimir effect - Wikipedia

    en.wikipedia.org/wiki/Casimir_effect

    Each energy level E n depends on the shape, and so one should write E n (s) for the energy level, and E(s) for the vacuum expectation value. At this point comes an important observation: The force at point p on the wall of the cavity is equal to the change in the vacuum energy if the shape s of the wall is perturbed a little bit, say by δs, at ...

  9. De Sitter space - Wikipedia

    en.wikipedia.org/wiki/De_Sitter_space

    More specifically, de Sitter space is the maximally symmetric vacuum solution of Einstein's field equations with a positive cosmological constant (corresponding to a positive vacuum energy density and negative pressure).