In a first, transmon qubit achieves a coherence time of one millisecond

Researchers at Aalto University in Finland have achieved a breakthrough in quantum computing by extending the coherence time of a superconducting transmon qubit to over one millisecond, with a median coherence time of about 0.5 milliseconds. This marks a new world record, significantly surpassing the previous best echo coherence times of around 0.6 milliseconds. The team accomplished this by using ultra-clean superconducting films, precise electron-beam lithography, and meticulous fabrication of Josephson junctions, all performed in a highly controlled cleanroom environment. Cooling the chip to near absolute zero and employing specialized low-noise amplifiers further preserved the qubit’s fragile quantum state. This advancement is crucial because longer coherence times allow qubits to perform more quantum operations before errors occur, enhancing the reliability and practicality of quantum computers. While this milestone is promising for the development of quantum sensors, simulators, and computers, scaling the technology to many qubits on a single chip with similar coherence remains a significant challenge. To