Imagine that a person takes time travel and kills his mother (yes, that sounds terrible). A paradox arises: how can he exist if his mother could not give birth to him?
There is a similar paradox in quantum computing theory. This theory is used to solve complex mathematical problems. But it can seriously disrupt the question of timing.
An international team of scientists has developed a way to solve quantum equations without breaking causation. They published their research in the journal Quantum Information.
The scientists decided to use an open time-like curve instead of a closed time-like curve. Both time loops are possible within Albert Einstein's General Relativity and allow travel through wormholes.
The closed timelike curve creates a causal paradox, as in the example where a man killed his mother in the past. This is because an object that has entered the wormhole can interact with causal factors from its own past.
But in the case of an open timelike curve, the object does not interact with these factors.
"He is completely isolated from any factors that influence his past during time travel," the study says. "This happens naturally in cases where the entrances to the wormholes are spatially separated."
Fundamental limitations of quantum theory have been violated, such as the uncertainty principle, the study explains. Scientists adapted the rules, which allowed them to solve equations that at first glance did not have a solution.
Promotional video:
In the case of an open time-like curve, "a time-traveling particle has the potential to break causation, but its complete isolation ensures that causality is never broken," the study said. The rules are modified to solve equations, avoiding the paradox of broken causation.