Specifically, they suggested that wormholes are each pairs of black holes that are entangled with one another.

Entangled black holes could be generated in a number of ways. For instance, a pair of black holes could in principle be made simultaneously, and these would automatically be entangled. Alternatively, radiation given off by a black hole could be captured and then collapsed into a black hole, and the resulting black hole would be entangled with the black hole that supplied the ingredients for it.

Maldacena and Susskind not only suggested that wormholes are entangled black holes, but they argued that entanglement in general was linked to wormholes. They conjectured that entangled particles such as electrons and photons were connected by extraordinarily tiny wormholes.

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Jensen and Karch found that if one imagined entangled pairs in a universe with four dimensions, they behaved in the same way as wormholes in a universe with an extra fifth dimension. Essentially, they discovered that entanglement and wormholes may be one and the same.

“Entangled pairs were the holographic images of a system with a wormhole,” Jensen said. Independent research from theoretical physicist Julian Sonner at the Massachusetts Institute of Technology supports this finding.