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Bugs in quantum computers are the biggest obstacle to their widespread use. But now, a team of scientists claims that, using an antimony atom and the Schrödinger’s Cat thought experiment, they could have found a way to stop them.
Scientists used the famous thought experiment of “Gato de Schrödinger” to find a way to solve the big problem of future quantum computers: the error elimination.
The new method, revealed this Wednesday in a study at Nature Physicsencodes quantum information in a antimony atom.
As explained by , an antimony atom has eight possible states, which allows data to be stored more securely than in a two-state quantum bit (qubit).
A vital step has thus been taken to reduce the likelihood of errors occurring in quantum systems and, when they do occur, make them more easily detectable and correctable – a fundamental obstacle to the development of functional quantum computers.
First conceived by physicist Erwin Schrödinger in 1925, his thought experiment describes the strange rules of the quantum world.
Schrödinger imagined a cat inside a box with a vial of poison with an opening mechanism controlled by radioactive decay – a completely random quantum process.
Until the box is opened and the cat observed, the rules of quantum mechanics theorize that the mythical feline will exist in a superposition of states: i.e, simultaneously dead and alive.
In the case of a qubit, as Live Science explains, quantum information relating to the 0 or 1 states of a classical computer can be encoded in the “’spin up”’ and “’spin down”’ states of an atom.
If noise inside a quantum computer causes this spin to change suddenly (as often happens), the quantum state is lost, producing an error and destroying the information contained therein.
Here comes antimony
To get around this problem, the researchers behind the new study incorporated a antimony atom (which has eight different rotation directions), inside a silicon quantum chip.
The antimony atom’s six additional spin directions (achieved by the composite nature of the atom adding several individual spins) mean that, unlike a system of two spin states, a single error is no longer enough to destroy the encoded information.
“As the proverb says, a cat has seven lives. A small scratch is not enough to kill you. Our metaphorical ‘cat’ really has seven lives: in other words, it would take seven consecutive errors to transform the ‘0’ into a ‘1’!”, said the co-author of the study Benjamin Wilhelmfrom the University of New South Wales (UNSW), in Australia, in .
With this system in place, the researchers now intend to demonstrate a method of detecting and correcting errors on their chip, a feat that is considered an “Holy Grail” in the field of quantum computing.
“If an error occurs, we detect it immediately and can correct it before more errors accumulate,” began explaining Andrea Morello, another author of the study, from UNSW, cited by Live Science.
“To continue with the ‘Schrödinger’s Cat’ metaphor, it’s as if we see our cat coming home with a big scratch on its face. It’s far from dead, but We know he was involved in a fight; We can go look for whoever caused the fight, before it happens again and our cat suffers more injuries,” he concluded.
