Improving Measurements by Reducing Quantum Noise

Researchers from Vienna University of Technology have built a new interferometer for trapped, ultracold atomic gases. By strongly suppressing the quantum noise, which ultimately limits the performance of interferometers, they were able to curb the effect of atomic interactions, and increase the interrogation time of their interferometer. This should yield more precise measurements. If you want to measure something very precisely, such as slight variations of a length, then you are very likely to use light waves. However, many effects, such as variations of gravity, or surface forces, can only be measured using particles that have a mass. Since, according to the rules of quantum mechanics, massive particles also behave like waves, interferometers can be built in which single atoms or even entire atomic clouds are used instead of light. A team from the Vienna University of Technology has now been able to develop a Mach-Zehnder interferometer for Bose-Einstein condensates containing about a thousand atoms trapped by an atom chip.