Wireless carriers invest a lot of technology to overcome the problem of noise. For a team of scientists exploring the atomic realm, measuring small fluctuations in noise could be the key to discovery.
Physicists can learn a lot by studying noise, even though it's thought of as a nuisance. They can learn a lot from measuring the noise in a material. It's hard to measure the noise in space or time.
A team of researchers at the University of Wisconsin-Madison have developed a technique to measure noise in a material using diamonds, and they can use this information to learn the spatial structure and time-varying nature of the noise. This technique, which relies on tracking tiny fluctuations in magnetic fields, is an improvement over previous methods.
De Leon is a leader in the fabrication of nitrogen-vacancy centers. The diamond's lattice of carbon atoms in which a carbon is replaced by a nitrogen atom is referred to as a diamond's lattice. One of the few tools that can measure changes in magnetic fields at the scale and speed needed for critical experiments is diamonds.
When de Leon's team worked out a way to harness multiple NV centers at the same time, they could measure the spatial structure of noise in a material. De Leon said that this opens the door to understanding the properties of materials with bizarre quantum behaviors that until now have been analyzed only theoretically.
De Leon said it was a fundamentally new technique. From a theoretical point of view, it would be very powerful to be able to do this. The audience that I think is most excited about this work is the theorists of Condensed Matter.
A material first explored in theories nearly 50 years ago is a quantum spin liquid. The stability of a magnetic material when cooled to a certain temperature is different to that of a quantum spin liquid.
It's difficult to map out a magnetic field in a quantum spin liquid because there's no static magnetic ordering. There isn't a way to directly measure the two-point magnetic field correlation, and what people are doing is trying to find complicated proxies for that measurement.
Researchers can detect how electrons and their spins are moving in a material by measuring magnetic fields at multiple points. The team applied a laser to a diamond and then detected two spikes of photon counts from a pair of centers at the same time. It was impossible to distinguish the magnetic field signals generated by a material of interest from the noise of the diamond when previous techniques were used.
There's no way to tell the difference between the two spikes because one is a signal and the other is from the local environment. One correlation is from the signal we're applying and the other is not. We can measure that, which is something people have never been able to do before.
They have been in touch a lot since they met at Harvard. De Leon said that long-distance collaboration became more attractive as most interactions took place over the internet.
The study's lead author was a research associate in de Leon's group. De Leon said that contributions by the team were crucial to designing the experiments. The paper's authors included two of de Leon's interns, Laura Futamura and Ahmed Abdalla, who were both interns in the QURIP program.
The article is in Science.
There is more information about the study by Rovny and his colleagues. There is a science.ade9858
Journal information: Science
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