Caltech Finds Quantum Computers Need Far Fewer Qubits

Researchers at the California Institute of Technology theorize that a functional quantum computer may require far fewer qubits than previously thought, making it feasible for the first quantum computer to be deployed before the end of the decade. 

Caltech researchers, working with a Caltech-linked start-up, Oratomic, said that by reducing the errors that “riddle today’s rudimentary quantum computers,” a functional quantum computer could be built with as few as 10,000 to 20,000 qubits. 

It was previously thought that millions of qubits were necessary for a quantum computer to function properly, said Caltech. A qubit is the basic unit of a quantum computer and the equivalent of a bit in a classical computer to encode information in binary.

“The need for fewer qubits means that quantum computers could, in theory, be operational by the end of the decade,” Caltech said. 

Moving atoms with optical tweezers

The theoretical innovation is a proposed error-correction architecture that leverages “neutral-atom systems,” in which atoms can be physically moved and connected across large distances using lasers called “optical tweezers.” 

“We are developing new architectures for neutral-atom quantum processors that dramatically reduce the resource estimates for fault-tolerant quantum computing,” said Caltech theoretical physicist John Preskill on Tuesday, adding: 

Related: Quantum computers need fewer qubits to crack crypto than thought: Google

Manuel Endres, a professor of physics at Caltech who recently created the largest qubit array ever assembled, said: 

The new tech allows each logical qubit to be encoded with as few as five physical qubits instead of around a thousand required by conventional methods, said Caltech.

“It’s actually very surprising how well this works. It’s what we call ultra-efficient error correction,” Endres said. 

Quantum frontiers closer than they appear

Oratomic said it will work in close collaboration with Caltech’s Advanced Quantum Computing Mission, with ongoing research into quantum information processing and the goal of building the world’s first utility-scale fault-tolerant quantum computer.

The research comes just a day after Google released a paper claiming that quantum computers could potentially break Bitcoin’s cryptography in nine minutes, needing much less computing power than originally thought.  

Meanwhile, Google urged crypto developers in its paper this week to transition blockchains to post-quantum cryptography, or PQC, now rather than waiting for real threats to emerge.

Last week, the internet giant set a 2029 timeline for its PQC migration, warning that “quantum frontiers” could be closer than they appear.

Magazine: Nobody knows if quantum secure cryptography will even work