Boosting Quantum Devices

MIT physicists, inspired by noise-canceling headphones, have advanced the coherence time of quantum bits by 20-fold, marking significant progress for quantum computing. The team used an “unbalanced echo” technique to counteract system noise, and they believe further improvements are possible. This breakthrough has vast potential, from quantum sensors in biology to advancements in quantum memory.



MIT researchers develop a protocol to extend the life of quantum coherence.

For years, researchers have tried various ways to coax quantum bits — or qubits, the basic building blocks of quantum computers — to remain in their quantum state for ever-longer times, a key step in creating devices like quantum sensors, gyroscopes, and memories.

A team of physicists from MIT have taken an important step forward in that quest, and to do it, they borrowed a concept from an unlikely source — noise-canceling headphones.


Led by Ju Li, the Battelle Energy Alliance Professor in Nuclear Engineering and professor of materials science and engineering, and Paola Cappellaro, the Ford Professor of Engineering in the Department of Nuclear Science and Engineering and Research Laboratory of Electronics, and a professor of physics, the team described a method to achieve a 20-fold increase in the coherence times for nuclear-spin qubits. 

The work is described in a paper published in Physical Review Letters. The first author of the study is Guoqing Wang PhD ’23, a recent doctoral student in Cappellaro’s lab who is now a postdoc at MIT.


“This is one of the main problems in quantum information,” Li says. “Nuclear spin (ensembles) are very attractive platforms for quantum sensors, gyroscopes, and quantum memory, (but) they have coherence times on the order of 150 microseconds in the presence of electronic spins … and then the information just disappears. 

What we have shown is that, if we can understand the interactions, or the noise, in these systems, we can actually do much better.”  READ MORE...