A new study from researchers at the Hebrew University of Jerusalem and Cornell University has revealed a new method to significantly suppress spin decoherence in alkali-metal gases, potentially revolutionizing quantum sensing and information technologies.
The findings, published in Physical Review Letters, demonstrate an order-of-magnitude reduction in spin relaxation rates at low magnetic fields.
The study was led by Mark Dikopoltsev and Avraham Berrebi, under supervision of Uriel Levy from the Hebrew University’s Institute of Applied Physics and Nano Center, and Or Katz from Cornell University.
Spin decoherence, the process by which quantum spin information is lost due to environmental interactions, is a key obstacle in the development of quantum technologies. This research specifically examined the decoherence of hot cesium spins, which are primarily affected by spin-rotation interactions during collisions with nitrogen molecules and through absorption of near-resonant light.
The team demonstrated that these decoherence effects can be dramatically suppressed by applying low magnetic fields—achieving an order-of-magnitude reduction in spin relaxation rates. This suppression extends beyond previously known regimes such as spin-exchange relaxation-free (SERF), showing that magnetic fields can also control mechanisms that relax electron spins, rather than just conserve them.
“Our results show that low magnetic fields are not just useful for avoiding decoherence from random, spin-conserving interactions,” said Dikopoltsev.
“They can actively suppress more damaging relaxation processes, giving us a powerful tool for preserving spin coherence.”
This discovery enhances fundamental understanding of spin dynamics and provides new strategies for controlling quantum states in hot atomic vapours. It lays the groundwork for future advancements in atomic clocks, quantum memory, magnetometry, and other technologies where long spin coherence times are critical.
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