IBM challenges Google’s quantum superiority claim

The Sycamore quantum processor from Google relies on a rectangular lattice work of 54 qubits, with each connected with couplers to its four neighbors. (Google)

Google researchers claimed a breakthrough with a quantum computer in a paper published in Nature on Wednesday, stating the device had performed a calculation not achievable with existing computers.

The researchers in Santa Barbara, California, said their quantum computer with its Sycamore processor finished a mathematical calculation in 3 minutes, 20 seconds, which would take the world’s supercomputers 10,000 years to complete.

The Google scientists called the calculation by its Sycamore processor “an experimental realization of quantum supremacy for this specific computational task, heralding a much-anticipated computing paradigm.”

While the feat is arguably revolutionary, it has already been called into question by Google competitor IBM. IBM argued that a “classical” computer system can perform the same mathematical task that Google undertook in 2.5 days and “with far greater fidelity.”

IBM’s reaction to Google’s work, posted online Monday, was based on a leaked preprint of Google’s paper that was widely reported in September.

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In quantum computing, quantum bits are known as qubits, and they can represent both zeroes and ones at the same time. When qubits are put in sequence they can represent different states of matter, making it possible to complete computations quickly—exponentially faster than many conventional machines.

IBM said it has a 53-cubit processor that is similar to the processor used by Google. Using the original meaning of the term “quantum supremacy” that was proposed in 2012—that quantum computers can do things that classical computers can’t—“this threshold has not been met.” The IBM team urged the quantum computing community to treat claims of quantum supremacy “with a large dose of skepticism.”

The research into quantum computing has reached a furious pace, partly because national security experts worry it could be used to break powerful encryption to achieve cyber attacks. The U.S. and China have research work underway and consider the technology a matter of national security. The U.S. announced a $1.2 billion National Quantum Initiative in 2019, while China has been building a national quantum lab and  has been racking up patents

For the private sector—including IBM, Google, Intel and Microsoft—quantum computers can potentially be used to make extremely fast calculations that will be useful in artificial intelligence work.

Google said its Sycamore processor consists of a two-dimensional array of 54 qubits, where each qubit is coupled to its neighbors in a rectangular lattice. “A key systems engineering advance of this device is achieving high-fidelity single- and two-qubit operations with simultaneous gate operations on many qubits,” the Google researchers said.