Quantum advance cuts qubit needs from 1000 to 5, brings practical computing closer Caltech researchers reduce qubit needs, speeding up path to fault-tolerant quantum computers Scientists at California Institute of Technology and startup Oratomic have developed a method to drastically cut the number of qubits needed for fault-tolerant quantum computing, potentially accelerating the arrival of practical machines. The team says a fully functional quantum computer could operate with as few as 10,000 to 20,000 qubits, far below the millions previously believed necessary. The advance comes from a new quantum error-correction architecture that reduces the number of redundant qubits required to fix errors, one of the biggest challenges in building reliable quantum systems. Quantum computers rely on qubits, which are highly sensitive and prone to errors. Existing methods often require about 1,000 physical qubits to create a single logical qubit, making large-scale systems difficult to build. Fewer qubits, faster future The researchers tackled this problem using neutral atom systems, where atoms act as qubits and are arranged using laser beams known as optical tweezers. Unlike other platforms, these atoms can be moved and connected across long distances. “Unlike other quantum computing platforms, neutral atom qubits can be directly connected over large distances,” said Manuel Endres. “Optical tweezers can shuttle one atom to the other end of the array and directly entangle it with another atom.” This flexibility allows for high-rate error-correction codes, where each physical qubit can support multiple logical qubits. As a result, a single logical qubit could be built using as few as five physical qubits. “It’s actually very surprising how well this works. It’s what we call ultra-efficient error correction,” Endres said. The approach builds on rapid advances in neutral atom systems, including arrays with more than 6,000 qubits already demonstrated in laboratories. The architecture also takes advantage