Quantum sensors can measure extremely small changes in an environment by taking advantage of quantum phenomena like entanglement, where entangled particles can affect each other, even when separated by great distances. Ultimately, say the researchers, they hope to be able to create and use these sensors in applications such as detecting and diagnosing disease, predicting volcanic eruptions and earthquakes, or exploring underground without digging.
Now, by harnessing a unique physics phenomenon, the researchers say they have calculated a way to develop a sensor that has a sensitivity that increases exponentially as it grows, without using more energy.
"This could even help improve classical sensors," says Prof. Aashish Clerk, co-author of a paper on the research. "It's a way to build more efficient, powerful sensors for all kinds of applications."
Quantum sensors use atoms and photons as measurement probes by manipulating their quantum state. Increasing the sensitivity of these sensors - and traditional sensors - often means developing a bigger sensor or using more sensing particles. Even so, say the researchers, such moves only increase the sensitivity of quantum sensors equal to the number of particles that are added.
Wondering if there was a way to increase the sensitivity even more, the researchers say they imagined creating a string of photonic cavities, where photons can be transported to adjacent cavities. Such a string could be used as a quantum sensor. This then brought up the question, if they created a longer and longer chain of cavities, would the sensitivity of the sensor be greater?
In systems like this, say the researchers, photons could dissipate - leak out of the cavities and disappear. But by harnessing a physics phenomenon called non-Hermitian dynamics , where dissipation leads to interesting consequences, they were able to calculate that a string of these cavities would increase the sensitivity of the sensor much more than the number of cavities added. In fact, they say, it would increase