If a person travels back in time and kills her own mother, well that’s pretty sinister—but it also creates for her an existential paradox. How does she exist if her mother doesn’t give birth to her?
Quantum computing theory was plagued by a similar paradox. It could be used to solve very complex mathematical problems, but to do so could seriously mess with time.
An international team of scientists has developed a way, however, for quantum computing to use time travel without breaking causality. They published their study Nov. 24 in the journal Quantum Information.
The key is using open timelike curves (OTCs) instead of closed timelike curves (CTCs). Both are time-loops, which are made possible within Albert Einstein’s General Relativity theory by traveling through wormholes.
The CTCs create causal paradoxes, similar to the woman killing her mother in the past. This happens because an object entering a wormhole can interact with causal factors in its own past. But, in the case of OTCs, the object cannot interact with those factors.
