The Elements of Innovation Discovered
The Elements of Innovation Discovered
Metal Tech News - February 22, 2025
Quantum computing leverages the Schrödinger's cat principle through qubits, the quantum realm equivalent of computer bits.
Left to right: Quantum computing researchers Benjamin Wilhelm, Xi Yu, Andrea Morello and Danielle Holmes with a cat that has a greater than 50-50 chance of still being alive.
Antimony is a heavy metalloid, an element with both metal and non-metal properties.
Quantum engineers at the University of New South Wales (UNSW) have achieved a breakthrough in quantum computing by creating a real-world version of Schrödinger's cat inside a silicon chip. Using an antimony atom's unique spin properties, the team has developed a more resilient method for quantum error correction – bringing the dream of stable, scalable quantum computers closer to reality.
Schrödinger's cat is a famous thought experiment in quantum mechanics that illustrates the concept of superposition – the idea that a quantum system can exist in multiple states at once until it is observed. In the experiment, a cat is placed in a sealed box with a radioactive atom that has a 50% chance of decaying and triggering a deadly poison. According to quantum theory, until the box is opened and the cat is observed, it exists in a superposition of both alive and dead states simultaneously. This paradox highlights the strange and counterintuitive nature of quantum mechanics.
"No one has ever seen an actual cat in a state of being both dead and alive at the same time, but people use the Schrödinger's cat metaphor to describe a superposition of quantum states that differ by a large amount," says UNSW Professor Andrea Morello, who led a study on antimony qubits published in Nature Physics.
In quantum computing, the Schrödinger's cat principle is leveraged through qubits, the quantum realm equivalent of the bits that store and transfer data in classical computers.
Unlike classical computers, where each bit represents either a zero (off) or one (on), qubits exist in superposition – both zero and one and neither of these states at the same time. However, qubits are highly susceptible to errors from environmental interference.
"If the qubit is a spin, we can call 'spin down' the '0' state, and 'spin up' the '1' state. But if the direction of the spin suddenly changes, we have immediately a logical error: 0 turns to 1 or vice versa, in just one go. This is why quantum information is so fragile," Benjamin Wilhelm, a quantum engineer and co-author of the study.
Left to right: Quantum computing researchers Benjamin Wilhelm, Xi Yu, Andrea Morello and Danielle Holmes with a cat that has a greater than 50-50 chance of still being alive.
The team of UNSW quantum scientists decided to leverage the complexities of an antimony atom to provide Schrödinger's cat with multiple lives.
"In our work, the 'cat' is an atom of antimony," says Xi Yu, lead author of the paper.
Antimony was chosen because it has a heavy atom that has eight different spin directions, which means a single error is not enough to scramble the quantum code.
Antimony is a heavy metalloid, an element with both metal and non-metal properties.
"The spin of antimony can take eight different directions, instead of just two. This may not seem much, but in fact it completely changes the behaviour of the system," Yu said. "A superposition of the antimony spin pointing in opposite directions is not just a superposition of 'up' and 'down', because there are multiple quantum states separating the two branches of the superposition."
Because it takes multiple consecutive errors to corrupt data, this approach significantly improves error correction – one of the biggest hurdles in developing reliable quantum computers.
"As the proverb goes, a cat has nine lives. One little scratch is not enough to kill it. Our metaphorical 'cat' has seven lives: it would take seven consecutive errors to turn the '0' into a '1'!" the study's lead author added.
To make their technology easier to adopt by a sector built around classical computers, the UNSW scientists embedded their antimony cat inside a silicon quantum chip that is similar to the ones we have in our computers and smartphones.
The chip was fabricated by Danielle Holmes, a postdoctoral quantum computing engineer at UNSW, the atom of antimony was inserted in the chip by colleagues at the University of Melbourne.
"By hosting the atomic 'Schrödinger cat' inside a silicon chip, we gain an exquisite control over its quantum state – or, if you wish, over its life and death," says Holmes. "Moreover, hosting the 'cat' in silicon means that, in the long term, this technology can be scaled up using similar methods as those we already adopt to build the computer chips we have today."
The much harder-to-corrupt qubit inserted into a silicon chip similar to what is already widely used opens the door to a new way to perform quantum computations.
"A single, or even a few errors, do not immediately scramble the information. If an error occurs, we detect it straight away, and we can correct it before further errors accumulate," Prof. Morello says. "To continue the 'Schrödinger cat' metaphor, it's as if we saw our cat coming home with a big scratch on his face. He's far from dead, but we know that he got into a fight; we can go and find who caused the fight, before it happens again and our cat gets further injuries."
With more than 17 years of covering mining, Shane is renowned for his insights and in-depth analysis of mining, mineral exploration, and technology metals.
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