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UChicago scientists discover way to make quantum states last 10,000 times longer:
A team of scientists at the University of Chicago's Pritzker School of Molecular Engineering announced the discovery of a simple modification that allows quantum systems to stay operational—or "coherent"—10,000 times longer than before.
[...] Quantum states need an extremely quiet, stable space to operate, as they are easily disturbed by background noise coming from vibrations, temperature changes or stray electromagnetic fields.
Thus, scientists try to find ways to keep the system coherent as long as possible. One common approach is physically isolating the system from the noisy surroundings, but this can be unwieldy and complex. Another technique involves making all of the materials as pure as possible, which can be costly. The scientists at UChicago took a different tack.
[...] In tandem with the usual electromagnetic pulses used to control quantum systems, the team applied an additional continuous alternating magnetic field. By precisely tuning this field, the scientists could rapidly rotate the electron spins and allow the system to "tune out" the rest of the noise.
"To get a sense of the principle, it's like sitting on a merry-go-round with people yelling all around you," Miao explained. "When the ride is still, you can hear them perfectly, but if you're rapidly spinning, the noise blurs into a background."
This small change allowed the system to stay coherent up to 22 milliseconds, four orders of magnitude higher than without the modification—and far longer than any previously reported electron spin system. [...] The system is able to almost completely tune out some forms of temperature fluctuations, physical vibrations, and electromagnetic noise, all of which usually destroy quantum coherence.
Journal Reference:
Kevin C. Miao, Joseph P. Blanton, Christopher P. Anderson, et al. Universal coherence protection in a solid-state spin qubit [$], Science (DOI: 10.1126/science.abc5186)
(Score: 0) by Anonymous Coward on Saturday August 15 2020, @09:12PM
(same poster).
A good example of resonance that I think of would be like a swing. You thrust yourself forward on a swing and then you get swung back and then as you go forward you apply more force again. If you time your force properly the force you apply to the prior forward motion will compound efficiently. With each iteration the force compounds with the prior forward force resulting in larger and larger swings each time.
That's resonance. The compounding effect of a force being applied during each periodic iteration of an event.
In stochastic resonance there doesn't appear to be a compounding effect after each iteration of an event. It just looks like ... constructive interference occurs just once to boost the signal past a threshold while the noise stays below the threshold so that you can detect the signal. but, as I said, I guess they call that resonance as well.