^{(Left) the trapped quantum fluid as seen under a microscope and (right) the shapes of the individual harmonic oscillation states of the quantum fluid when the fluid is trapped in a dip in the intensity of the laser beams (dashed line). Credit: Nature Communications (2022). DOI: 10.1038/s41467-022-34440-0}

^{By Dr. Inés Urdaneta, Physicist at Resonance Science Foundation}

We are used to the notion of classical harmonic oscillators; these are oscillators fluctuating coherently -this is, symmetrically- around their equilibrium position, experiencing a restoring force F proportional to the displacement x (as F = -kx, being k a positive constant commonly known in the mechanics of ideal springs).  

If F is the only force acting on the system (which means there is no friction with the environment) the system is called a simple harmonic oscillator, and it undergoes a sinusoidal oscillations about the equilibrium point, with a constant amplitude and a constant frequency that does...