The wormholes are theoretical portals through space-time that could create shortcuts for long journeys across our Universe. They have entered modern physics soon after the discovery of black holes. In both cases it took decades to understand their rich physical content and to realize that they may play a role in Nature. However, while there is increasing evidence for the existence of astrophysical black holes, the traversable wormholes remain an interesting possibility.
Blázquez-Salcedo et al. constructed a specific example of a class of traversable wormholes in four space-time dimensions. Image credit: NASA / G. Bacon, STScI.
“In theory, space-time could be bent and curved without massive objects,” said Dr. Jose Luis Blázquez-Salcedo, a researcher in the Departamento de Física Teórica and IPARCOS at the Universidad Complutense de Madrid.
“In this scenario, a wormhole would be an extremely curved region in space-time that resembles two interconnected funnels and connects two distant points in space, like a tunnel.”
“From a mathematical perspective such a shortcut would be possible, but no one has ever observed a real wormhole,” he said.
“Moreover, such a wormhole would be unstable. If for example a spaceship were to fly into one, it would instantly collapse into a black hole.”
“The connection it provided to other places in the Universe would be cut off.”
Previous models suggested that the only way to keep the wormhole open is with an exotic form of matter that has a negative mass.
In the new study, Dr. Blázquez-Salcedo and his colleagues from the Universität Oldenburg and the Universidade de Aveiro demonstrated that the wormholes could be traversable without such exotic matter.
They combined elements of relativity theory with elements of quantum theory and classic electrodynamics theory.
In their model, the researchers consider certain elementary particles such as electrons and their electric charge as the matter that is to pass through the wormhole.
As a mathematical description, they chose the Dirac equation, a formula that describes the probability density function of a particle according to quantum theory and relativity as a so-called Dirac field.
“It’s the inclusion of the Dirac field into our model that permits the existence of a wormhole traversable by matter, provided that the ratio between the electric charge and the mass of the wormhole exceeds a certain limit,” they said.
“In addition to matter, signals — for example electromagnetic waves — could also traverse the tiny tunnels in space-time.”
“The microscopic wormholes postulated by our team would probably not be suitable for interstellar travel,” they added.
“Moreover, the model would have to be further refined to find out whether such unusual structures could actually exist.”
The team’s paper was published in the journal Physical Review Letters.
Jose Luis Blázquez-Salcedo et al. 2021. Traversable Wormholes in Einstein-Dirac-Maxwell Theory. Phys. Rev. Lett 126 (10): 101102; doi: 10.1103/PhysRevLett.126.101102