As loyal readers know, here at Discovery News World Headquarters we like to keep a little light reading in the break room, next to the quantum espresso machine. So we were excited to see this item in the open-access journal npj Quantum Information.
It seems that an international team of scientists has published new research that suggests quantum computers could potentially address intractable mathematical problems - by sending data back in time.
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Yeah, it gets complicated, but here goes: The time-traveling quantum computer model would create a batch of information that - through the weirdness of quantum physics - could be sent though a "closed timelike curve."
From the news release accompanying the paper's publication: "These are paths through the fabric of spacetime that loop back on themselves. General relativity allows such paths to exist through contortions in spacetime known as wormholes."
But closed timelike curves present problems of causality. It's the old time-travel dilemma - if you go back in time and kill your grandfather, would you exist to time travel in the first place?
With quantum physics in play, however, these packets of information, or messages, can be "entangled" with another system in the laboratory. Entanglement, an effect only possible in the quantum realm, would create correlations between the traveling message and the laboratory system. Those correlations, in turn, can power new kinds of quantum computation.
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Furthermore, the quantum computing system would skirt the causality problem by creating an "open timelike curve" that does not allow direct interaction between the message's past and present. The message sent back in time would be locked and could never be opened. But the very sending of the message triggers the entanglement phenomenon, which provides the computing power used to solve the problem.
Something like that. It took us a few cups of quantum espresso to really get a handle on things, but you can read all about it at the npj Quantum Information page.
In any case, the research team has an impressive list of credentials. The paper was co-authored by eight scientists from the following institutions: the National University of Singapore; Tsinghua University in China; the University of Oxford; the Australian National University in Canberra; the University of Queensland in St Lucia, Australia; and QKD Corp in Toronto, Canada.