The Time Machine Factory [unspeakable, speakable] on Time Travel - TMF2024

Session

Session III. Space travel, wormholes

24 Sept 2024, 11:35

Vallauri Hall (INRiM historical building, Turin)

Conveners

Session III. Space travel, wormholes: Morning session

• David Kubiznak (Institute for Theoretical Physics, Charles University, Prague)

Session III. Space travel, wormholes: Afternoon session

• David Kubiznak (Institute for Theoretical Physics, Charles University, Prague)

114. Non-exotic modified gravity wormholes and closed timelike curves

Prof. Francisco S.N. Lobo (Institute of Astrophysics and Space Sciences - Departamento de Física da FCUL)

24/09/2024, 11:35

talk

The flaring-out condition at a wormhole’s throat is a fundamental aspect of wormhole physics, which, in the context of classical general relativity, leads to a violation of the null energy condition. In this work, we explore the broadest possible conditions under modified gravity, where the matter threading the wormhole throat satisfies the energy conditions. In fact, it is the higher-order...

104. Can one peek inside black holes using a wormhole?

Antonia Micol Frassino (Alcalá U. & ICCUB)

24/09/2024, 12:10

talk

In the extreme mass ratio limit, the evolution of the event horizon in a merging event between a large black hole and a small compact object can be computed exactly with elementary ray-tracing techniques. I will describe what happens when the small body is an Ellis-Bronnikov traversable wormhole. A double-mouth wormhole within the same universe is obtained by gluing two such geometries --- in...

95. Improvements on Casimir Wormholes

Remo Garattini (Università degli Studi di Bergamo)

24/09/2024, 14:10

talk

We describe the connection between a traversable wormhole and the Casimir effect. With the help of an equation of state we also discuss different forms of solutions related to the Casimir source. The effect of including an electromagnetic field, temperature and rotations to the original energy density are also discussed.

92. Nucleation of Wormholes and Topology Changes in Lorentzian Geometry.

Mr Alessandro Pisana (Brock University)

24/09/2024, 14:45

talk

The possibility that the topology of space can change even at a classical level in General Relativity necessitates abandoning either the causality conditions or the equivalence principle. If the causal structure is regarded as fundamental, topology changes are possible by allowing singularities, degenerate tetrads, or gravitational instantons, i.e., Riemannian solutions of the Einstein...

112. Z-machine, Levi-Civita Solution and Wormholes

Claudio Maccone (Istituto Nazionale di Astrofisica (INAF))

24/09/2024, 15:10

talk

In 1917 Tullio Levi-Civita exactly solved the Einstein-Maxwell equations for the artificial and very tiny gravitational field created by the energy of a static and extremely intense magnetic or electric field.
In 1995 Claudio Maccone extended that Levi-Civita solution so as to check its validity by virtue of the Z_machine existing at Sandia Labs in the USA.
In 2000 Dr. Slutz’s reply from...

86. Inaccessibility of traversable wormholes

Daniel Terno (Macquarie University)

24/09/2024, 15:35

talk

Wormhole solutions in general relativity have some spectacular local and global properties. An invariant characterisation of a wormhole's throat presents it as an outer marginal trapped surface subject to additional conditions. The requirement that this trapped surface forms within a finite time from the perspective of a distant observer leads to unusual properties of black and white holes and...