Spacetime, any mathematical model that combines space and time into a single continuum
spacetime | spacetime algebra | Spacetime | Maxwell's equations in curved spacetime | Doraemon: Nobita in the Wan-Nyan Spacetime Odyssey |
At some typical boundary regions such as null infinity, timelike infinity, spacelike infinity, black hole horizons and cosmological horizons, null tetrads adapted to spacetime structures are usually employed to achieve the most succinct Newman-Penrose descriptions.
Sometimes, especially in the theory of relativity as it is expressed by Minkowski, the path traced by an object through spacetime.
Its applications deal with domains where privileged directions appear, like concurrent processes, traffic networks, spacetime models, noncommutative geometry, rewriting systems and the modelling of biological systems.
American philosopher of physics John Stachel has used permutability of spacetime events to generalize Einstein's hole argument.
It is generated by two non-commuting subgroups: the Matzner–Misner group (after Richard Alfred Matzner and Charles W. Misner) of linear combinations (with constant coefficients) of the two Killing vector fields associated with the spacetime's axisymmetry and stationarity, and the Ehlers group.
According to Harman, everything is an object, whether it be a mailbox, a gas, the Commonwealth of Nations, Popeye, spacetime, a shadow or an eclipse.
In tribute to Wolfgang Rindler, the author of the standard introductory university-level textbook on relativity, hyperbolic coordinates of spacetime are called Rindler coordinates.
He became notable outside his field, especially among string theorists, in 1999 when he discovered the Algebraic holography (also called Rehren duality), a relation between quantum field theories AdSd+1 and conformal quantum field theories on d-dimensional Minkowski spacetime, which is similar in scope to the Holographic principle.
He was also considering reformulating his theory in four dimensional spacetime, since the properties associated with the higher dimensions are oscillatory and can be represented as fiber bundles over a 4D Minkowski manifold.
Of interest in this connection would be to see whether the LQG analogue of Minkowski spacetime breaks or preserves global Lorentz invariance, and Carlo Rovelli and coworkers have recently been investigating the Minkowski state of LQG using spin-foam techniques.
Edwin F. Taylor and John Archibald Wheeler (1963) Spacetime Physics, pages 27 to 38, New York: W. H. Freeman and Company, Second edition (1992).
Since the end of the eighties, the local quantum field theory approach due to Rudolf Haag and Daniel Kastler has been implemented in order to include an algebraic version of quantum field theory in curved spacetime.
In the context of general relativity, he is best known for his development (with Stanley Deser and Charles Misner) of the ADM formalism, roughly speaking a way of describing spacetime as space evolving in time, which allows a recasting of Einstein's theory in terms of a more general formalism used in physics to describe dynamical systems, namely the Hamiltonian formalism.
This notion of simplicial manifold is important in Regge calculus and Causal dynamical triangulations as a way to discretize spacetime by triangulating it.
Lasenby, Doran, and Gull of Cambridge University have proposed a new formulation of gravity, termed gauge theory gravity (GTG), wherein spacetime algebra is used to induce curvature on Minkowski space while admitting a gauge symmetry under "arbitrary smooth remapping of events onto spacetime" (Lasenby, et al.); a nontrivial proof then leads to the geodesic equation,
In the context of general relativity, he is best known for his development (with Richard Arnowitt and Charles Misner) of the ADM formalism, roughly speaking a way of describing spacetime as space evolving in time, which allows a recasting Einstein's theory in terms of a more general formalism used in physics to describe dynamical systems, namely the Hamiltonian formalism.
John DeChancie's Starrigger series uses vertically-aligned Tipler cylinders (officially called Kerr-Tipler objects) to create spacetime gateways along an intergalactic highway.