X-Nico

unusual facts about Spacetime


Timespace

Spacetime, any mathematical model that combines space and time into a single continuum


Construction of a complex null tetrad

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.

Counterpart theory

Sometimes, especially in the theory of relativity as it is expressed by Minkowski, the path traced by an object through spacetime.

Directed algebraic topology

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.

Event symmetry

American philosopher of physics John Stachel has used permutability of spacetime events to generalize Einstein's hole argument.

Geroch group

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.

Graham Harman

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.

Hyperbolic coordinates

In tribute to Wolfgang Rindler, the author of the standard introductory university-level textbook on relativity, hyperbolic coordinates of spacetime are called Rindler coordinates.

Karl-Henning Rehren

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.

Klaus Hasselmann

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.

Lorentz invariance in loop quantum gravity

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.

Minkowski diagram

Edwin F. Taylor and John Archibald Wheeler (1963) Spacetime Physics, pages 27 to 38, New York: W. H. Freeman and Company, Second edition (1992).

Quantum field theory in curved spacetime

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.

Richard Arnowitt

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.

Simplicial manifold

This notion of simplicial manifold is important in Regge calculus and Causal dynamical triangulations as a way to discretize spacetime by triangulating it.

Spacetime algebra

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,

Stanley Deser

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.

Tipler cylinder

John DeChancie's Starrigger series uses vertically-aligned Tipler cylinders (officially called Kerr-Tipler objects) to create spacetime gateways along an intergalactic highway.


see also