Profile
José Natário
mathematician and relativist, Instituto Superior Técnico, University of Lisbon
Natário studies the mathematics of general relativity and spacetime geometry. His 2002 paper specifies a warp geometry with zero expansion, showing that expansion behind a moving region and contraction ahead are not essential features of every such mathematical model. It also examines how light travels through these geometries and their global structure. The result broadens the geometries researchers can compare; it describes a spacetime model rather than a mechanism for constructing a drive.
Affiliations
- Instituto Superior Técnico, Universidade de Lisboa
Channels
Bibliography
A bibliography listing does not establish authorship. Credits appear under attribution.
Published bibliography entries: 2. Showing 1–2 of 2.
Listed work
Paper · 2002
Warp Drive With Zero Expansion
- José Natário(Author)
José Natário revisits the common explanation that Alcubierre's warp drive works by contracting space ahead of the bubble and expanding it behind. He shows this contraction and expansion is only a side effect of Alcubierre's particular choice, and builds a similar warp drive with no contraction or expansion at all. Describing warp spacetimes by a vector field on flat 3-space, he shows they always violate some energy condition and that the volume expansion is the field's divergence. Choosing a divergence-free field gives a volume-preserving warp drive. Simple examples show horizons and infinite blueshifts, and he also discusses the global and optical properties of these spacetimes.
Listed work
Paper · 2006
Newtonian limits of warp drive spacetimes
- José Natário(Author)
José Natário notes that the warp drive spacetime illuminates general relativity, but its meaning as a gravitational field is unclear. Newtonian limits are a standard tool for understanding and interpreting relativistic spacetimes. He therefore seeks a Newtonian limit of the warp drive spacetime. He defines Newtonian spacetimes with a potential function and shows they closely mirror their counterparts in Newtonian theory, especially with a dust source and cosmological constant. Such spacetimes always have a Newtonian limit with the same potential. He finds a class of warp drive spacetimes with Newtonian limits and applies the same method to the Schwarzschild solution and flat Friedmann-Robertson-Walker cosmologies.