The Harvard team has for the first time implemented all the key elements of scalable quantum computing and quantum error correction in an integrated quantum system, a decisive step towards building practical large-scale quantum computers. The latest results are published in a new issue of the journal Nature.
Physicists have unveiled a system that could solve a long-standing obstacle to a new generation of supercomputers. Image: physicist organization network
Quantum computers can encode information at the single-atom level, but have long been limited by the key bottleneck of quantum error correction. The new quantum system, built by the Harvard team, can detect and clean up errors below critical performance thresholds. According to many performance indexes, these experiments reach the highest level of any quantum platform so far, which provides a new way to break through the bottleneck of quantum error correction.
Quantum error correction is regarded as a key threshold for the development of quantum computing. Unlike traditional computers, which use 0 and 1 to encode information, quantum computers rely on the properties of quantum superposition and entanglement to store exponential information in a very small number of qubits. A system of about 300 qubits has more information capacity than the total number of particles in the known universe. However, quantum bits are prone to decoherence and loss of information, so reducing the error rate becomes the premise of developing large-scale quantum systems.
The team demonstrated a“Fault-tolerant” system of 448 neutral atomic qubits that can detect and correct errors in real time through mechanisms such as physical entanglement, logical entanglement and entropy removal, the contactless transmission of quantum states is realized by using“Quantum teleportation” and other techniques.
To test the scalability of the system, the team designed a deep quantum circuit with dozens of error-correcting steps to lower the error rate below the critical threshold. In this threshold range, further increase of qubits will not introduce additional errors, but will further suppress errors. The results are seen as an important advance in the field of quantum error correction over the past 30 years.
Hartmut Nevin, Google’s vice president of Engineering for the quantum AI team, said the results came at a“Very exciting” stage of the global qubit platform competition, “An important step toward building large-scale, practical quantum computers.”.