Chinese scientists at the University of Science and Technology of China (USTC) have made groundbreaking strides in the field of quantum computing by successfully achieving near-physical limit coherence times for room-temperature solid-state quantum systems. This important development was published on March 1, 2025, under the title "Solid-state spin coherence time approaching the physical limit" in the journal Science Advances.
The team, based within the USTC's Key Laboratory of Micro-Nano Magnetic Resonance, employed high-purity diamond quantum materials and characterized their solid-state spin systems using comprehensive noise spectra techniques. This innovative approach not only revealed new noise mechanisms dominated by non-local spin-lattice interactions but also allowed the researchers to overcome known coherence time limits, marking substantial progress for quantum systems operating at room temperature.
For many years, researchers have strived to create quantum systems with ultra-long coherence times, as such systems are foundational to quantum science and technology. Within the past few decades, significant progress has been made thanks to advancements in material synthesis and noise suppression techniques. Nevertheless, existing solid-state systems consistently failed to surpass the empirical coherence time limit of T2 = T1/2, where T2 refers to the spin coherence time, and T1 pertains to relaxation times—phenomena leading to limitations imposed by thermal dissipation within quantum systems.
To tackle this complex challenge, the research team began innovatively developing technologies aimed at producing high-purity diamond quantum systems and performing full-frequency characterization of quantum noise. Their combined use of material synthesis and physical control methods unveiled previously undiscovered noise spectra. This fresh insight offers new physical understandings of the coherence time limits experienced within solid-state electronic spin systems.
Notably, they uncovered non-local spin-lattice interactions as the primary contributor restricting electronic spin coherence time from achieving optimal physical limits, which contrasts with traditional theories positing local spin-lattice interactions as dominant. Their breakthrough offers a fundamental re-evaluation of prevailing conceptions within the field.
By implementing noise suppression techniques developed from their discoveries, the researchers enabled the coherence time of diamond single-spin quantum systems to exceed historical empirical limits. They achieved this remarkable feat with the longest coherence time currently recorded at room temperature, clocking in at 4.34 milliseconds.
This achievement not only propels forward the potential for solid-state quantum technologies but also establishes new avenues for exploring the rich mechanisms underlying interactions within solid materials. The results are significant for optimizing various solid-state quantum systems, which could lead to broader applications across quantum computing and information science.
Shuo Han, Xiangyu Ye, and doctoral student Xu Zhou are recognized as the joint first authors of the paper, with Professor Ya Wang serving as the corresponding author. This research was supported by funding from the National Natural Science Foundation and the Ministry of Science and Technology, among other entities.
These advances emerge as part of the USTC's commitment to leading innovation within quantum technology, as global interest and competition within the quantum computing sector intensify. This concerted focus on developing cutting-edge facilities and fostering collaboration, coupled with diligent investment, positions China to potentially remain at the forefront of quantum science and its applications.
The scientific community is closely monitoring these developments, as they stand to impact not only the theoretical aspects of quantum research but also practical implementations. The study’s conclusions could pave the way for novel applications across quantum teleportation, secure communication, and beyond, reinforcing the nation's growing influence on the global scientific stage.
Room-temperature quantum coherence systems hold immense promise for making quantum computing more viable and accessible. Scientists worldwide anticipate the continued breakthroughs from USTC and other institutions, as researchers strive to push the boundaries of what is technologically possible.
To access the research findings, visit the published work at here.