While practical quantum computers are still far off, the field has crossed some significant milestones in recent months. IBM unveiled its 127-qubit Eagle processor , the largest general-purpose quantum computer to date, while Boston start-up QuEra showed off a 256-qubit device aimed at solving a more limited palette of problems. The industry is also showing increasing maturity, with two companies going public and hardware-maker Honeywell and quantum software developer Cambridge Quantum merging to create Quantinuum.
Chinese researchers confirm that we have reached the era of quantum primacy by demonstrating that two different quantum computers can outperform classical ones on much larger problems than the one Google tackled in its landmark 2019 experiment. The first concrete demonstration of a quantum speedup for machine learning also increased the hope that the field could have synergies with AI. And quantum computers made from the same silicon as conventional chips crossed an important accuracy threshold that makes it possible for them to run leading error correction codes.
More recently, Microsoft claims to have validated the underlying physics of an exotic new approach called topological quantum computing. The technology could be far more stable and reliable than alternatives and the tech giant says it has now demonstrated that it can produce the quasiparticles needed to build topological qubits. But the field has been beset by false promises, setbacks and retractions in recent years, so many experts are likely to reserve judgement.
While quantum computers tend to hog the headlines, other quantum technologies have also made significant progress. In September, China revealed that it had built a city-wide quantum communication network in Hefei connecting 40 computers at government buildings, banks and universities. With Ireland signed onto the EuroQCI Declaration, all 27 members of the EU are now committed to building a continent-spanning quantum network for secure communications. Last December, British researchers backed by the Ministry of Defence demonstrated the first use of a quantum gravity sensor to reliably detect underground structures in real world conditions. And in March 2022, the European Space Agency announced a program to use similar technology to create gravity maps and vehicle-based sensors for next generation navigation systems.
There was also an intriguing development in quantum physics that could lay the foundation for future technologies. When two quantum systems become entangled actions carried out on one instantly affect the other, and this attribute is at the heart of many quantum technologies. Typically this effect is only found in subatomic particles, but researchers have now shown that they can entangle two aluminium drums about 10 microns across -- colossal objects in quantum terms. Beyond rewriting our assumptions about the limits of quantum mechanics the breakthrough could have implications for both quantum sensing and communication.