Decreasing the number of dimensions from three to two to one dramatically influences the physical behaviour of a system, causing different states of matter to emerge. In recent years, physicists have been using optical quantum gases to study this phenomenon.

In the new study, conducted in the framework of the collaborative research centre OSCAR, a team led by Frank Vewinger of the Institute of Applied Physics (IAP) at the University of Bonn looked at how the behaviour of a photon gas changed as it went from being 2D to 1D. The researchers prepared the 2D gas in an optical microcavity, which is a structure in which light is reflected back and forth between two mirrors. The cavity was filled with dye molecules. As the photons repeatedly interact with the dye, they cool down and the gas eventually condenses into an extended quantum state called a Bose–Einstein condensate.

Encoding an image into the quantum correlations of photon pairs makes it invisible to conventional imaging techniques.

Integer quantum Hall effect allows to gauge the resistance standard up to more than one part in a billion. Combining it with the speed of light, one obtains the.

Quantum squeezing is a concept in quantum physics where the uncertainty in one aspect of a system is reduced while the uncertainty in another related aspect is increased. Imagine squeezing a round balloon filled with air. In its normal state, the balloon is perfectly spherical. When you squeeze one side, it gets flattened and stretched out in the other direction. This represents what is happening in a squeezed quantum state: you are reducing the uncertainty (or noise) in one quantity, like position, but in doing so, you increase the uncertainty in another quantity, like momentum. However, the total uncertainty remains the same, since you are just redistributing it between the two. Even though the overall uncertainty remains the same, this ‘squeezing’ allows you to measure one of those variables with much greater precision than before.

This technique has already been used to improve the accuracy of measurements in situations where only one variable needs to be precisely measured, such as in improving the precision of atomic clocks. However, using squeezing in cases where multiple factors need to be measured simultaneously, such as an object’s position and momentum, is much more challenging.

In a research paper published in Physical Review Research (“Squeezing-induced quantum-enhanced multiphase estimation”), Tohoku University’s Dr. Le Bin Ho explores the effectiveness of the squeezing technique in enhancing the precision of measurements in quantum systems with multiple factors. The analysis provides theoretical and numerical insights, aiding in the identification of mechanisms for achieving maximum precision in these intricate measurements.