Search results
Results from the WOW.Com Content Network
familiar from quantum mechanics but interpreted in this context as coordinates of a quantum space or spacetime. These relations were proposed by Roger Penrose in his earliest spin network theory of space. It is a toy model of quantum gravity in 3 spacetime dimensions (not the physical 4) with a Euclidean (not the physical Minkowskian) signature.
Similarly, in Thermal quantum field theory a compactification of the euclidean time dimension leads to the Matsubara frequencies and thus to a discretized thermal energy spectrum. However, Klein's approach to a quantum theory is flawed [citation needed] and, for example, leads to a calculated electron mass in the order of magnitude of the ...
The implication is that a quantum field theory on noncommutative spacetime can be interpreted as a low energy limit of the theory of open strings. Two papers, one by Sergio Doplicher , Klaus Fredenhagen and John Roberts [ 5 ] and the other by D. V. Ahluwalia, [ 6 ] set out another motivation for the possible noncommutativity of space-time.
An objection to the practicality of building a Tipler cylinder was discovered by Stephen Hawking, who argued that according to general relativity it is impossible to build a time machine in any finite region that satisfies the weak energy condition, meaning that the region contains no exotic matter with negative energy.
In a similar way that gravity is the manifestation of the intrinsic curved geometry of spacetime in general relativity, the quantum properties here are the manifestation of another property of spacetime at small scales, its intrinsic non-differentiability. [6]
The causal sets program is an approach to quantum gravity.Its founding principles are that spacetime is fundamentally discrete (a collection of discrete spacetime points, called the elements of the causal set) and that spacetime events are related by a partial order.
In theoretical physics, quantum field theory in curved spacetime (QFTCS) [1] is an extension of quantum field theory from Minkowski spacetime to a general curved spacetime. This theory uses a semi-classical approach; it treats spacetime as a fixed, classical background, while giving a quantum-mechanical description of the matter and energy ...
The phenomenon of dimensional reduction has now been reported in a number of different approaches to quantum gravity. String theory, [2] causal dynamical triangulations, [3] renormalization group approaches, [4] noncommutative geometry, [5] loop quantum gravity [6] and Horava-Lifshitz gravity [7] all find that the dimensionality of spacetime appears to decrease from approximately 4 on large ...