Researchers in China have made a significant breakthrough in preserving quantum entanglement at room temperature. A team led by Shuo Ren and Rui-Jian Liang at the University of Science and Technology of China in Hefei successfully extended the lifetime of entanglement in a solid-state system by up to 240 times. They achieved this by transferring entangled states from the electron spins of atomic defects in a material to the spins of surrounding atomic nuclei, which are more resistant to environmental disturbances. The study was published in Physical Review Letters, a leading journal in physics. Quantum entanglement is a phenomenon in which two or more quantum particles become so deeply connected that the state of one instantly influences the state of the other, no matter the distance. This property is central to emerging fields like quantum computing and sensing, where entangled particles can perform tasks beyond the capabilities of classical systems. However, maintaining entanglement is challenging because quantum information is easily disrupted by environmental noise, such as thermal fluctuations. While cooling systems to near absolute zero can reduce this noise, researchers are now exploring more practical methods that allow qubits—quantum bits—to be more resilient to their environment. One promising approach involves "spin defects," which are atomic-scale imperfections in solid materials. These defects can store quantum information in the spin states of their electrons. For instance, "color centers" in silicon carbide—defects that absorb and emit light at specific wavelengths—are being studied for quantum sensing. When placed near the surface of a material, these defects interact strongly with external signals, making them ideal for sensing. However, their proximity to the surface also makes them more vulnerable to noise, causing the entanglement to decay quickly. To overcome this, Ren and Liang's team developed a method to transfer entanglement from the electron spins of color centers to the nuclear spins of nearby silicon atoms. Specifically, they used a "SWAP-gate" protocol, a sequence of control pulses that exchanges quantum states between two qubits. By transferring entanglement to silicon-29 nuclei—known for their resilience to noise—the team preserved the entangled state for much longer. The process allowed the electron to be used for fast control, while the nuclei acted as a memory for storing the entangled state. This technique increased the entanglement lifetime from just over 1 microsecond to over 240 microseconds, demonstrating a significant improvement in stability.