Google and NASA tackle Quantum Supremacy
Quantum supremacy is the idea, so far not demonstrated, that a sufficiently powerful quantum computer will be able to complete certain mathematical calculations that classical supercomputers cannot. Proving it would be very important because it could kick-start a market for devices that might one day crack previously unbreakable codes, boost AI, improve weather forecasts, or model molecular interactions and financial systems in great detail.
The agreement, signed in July, calls on NASA to “analyze results from quantum circuits run on Google quantum processors, and … provide comparisons with classical simulation to both support Google in validating its hardware and establish a baseline for quantum supremacy.”
Google confirmed that the agreement covered its latest 72-qubit quantum chip, called Bristlecone. While classical computers store information in binary bits that represent either 1 or 0, quantum computers use qubits that exist in an undefined state between 1 and 0. Using qubits could quickly provide solutions to some problems that could take classical computers much longer to compute.
Physicist John Martinis, who leads Google’s quantum computing effort, thinks that Bristlecone is capable of achieving quantum supremacy. However, not everyone agrees. In May, researchers from Alibaba’s Data Infrastructure and Search Technology Division published a paper suggesting that classical computers running simulations could match its performance, and that quantum chips with lower error rates might be needed.
Daniel Lidar, director of the Center for Quantum Information Science and Technology at the University of Southern California, also has some doubts. “It would seem that some additional form of error suppression would be necessary,” he told. “In addition, classical simulation methods have raised the bar several times over the past couple of years, and it is quite likely this trend will continue. Nevertheless, I would not rule out a quantum supremacy demonstration using Google’s Bristlecone system.”
The new collaboration between Google and NASA will work in this way: because Bristlecone requires superconducting circuits maintained at a temperature close to absolute zero, it cannot be moved from Google’s labs. Instead, researchers from the Quantum Artificial Intelligence Laboratory (QuAIL) at NASA’s Ames Research Center in Silicon Valley will connect to Bristlecone online, via Google’s Cloud API service. Google will also share its current software, which allows classical computers to simulate quantum circuits, so that NASA can develop and improve it.
Together, the two organizations will work out how to map “a diverse array of optimization and sampling problems” on Bristlecone’s gate-model quantum computing system. Early next year, when they have agreed on the problems and initial targets for simulation, NASA will code the software necessary to run those simulations on its petaflop-scale Pleiades supercomputer, which is also located at Ames. Pleiades is NASA’s most powerful supercomputer, currently ranked in the top 25 worldwide.
Around July of next year, 12 months from the signing of the contract, NASA will “compare results from classical simulation of quantum circuits to results from Google hardware.”
If things don’t go as planned, Google’s agreement has a five-year term within which “NASA will provide further mappings, improved circuit simulation techniques, more efficient compilations and results from circuit simulations.” Google will give QuAIL access to its quantum processor and software until at least 2023.