A recent collaboration between the National Institute of Optics of the National Research Council (CNR-INO), the Department of Physics of the University of Trento, Tifpa – National Centre of the National Institute for Nuclear Physics (INFN) – and a team of researchers led by cosmologist Ian Moss of the University of Newcastle could shed new light on the mechanisms that determine the stability of our universe.
According to modern physics, our universe is the result of interaction between particles and fields and could be in an equilibrium configuration, known as false vacuum, i.e. a partially “stable” state with a level of energy higher than the absolute minimum. This allows transition towards lower energy levels, triggered by quantum or thermal fluctuations that could “decay” to the lowest energy state, known as true vacuum. This process could take place on very different time scales with the formation of “bubbles” of true vacuum within false vacuum.
This phenomenon has very important implications on cosmological processes, so much so that the scientific community keeps on asking: in which type of vacuum is our universe immersed?
An answer to this question comes from the Pitaevskii Center for Bose-Einstein Condensation laboratories in Trento where researchers have prepared a “cloud” of ultracold sodium atoms which stimulates a state of false vacuum. Under different experimental conditions, they measured the time it takes atoms to change their configuration and reach the true vacuum state.
In addition to verifying that the behaviour of atoms was compatible with the numerical simulations of the system, the researchers ensured that the most established false vacuum decay theories were compatible with experimental observations.
The result, said Alessandro Zenesini, CNR-INO researcher who first worked on this study with his colleagues Giacomo Lamporesi and Alessio Recati, is that “once again, ultracold atoms prove to be an ideal platform for quantum simulation of both the extremely small and the extremely large: in this case, we used the magnetic properties of atoms to create artificial false and true vacuum states in an ultra-stable and controllable environment. This exquisite control of the degenerate atomic cloud allows us to study false vacuum decay in different experimental conditions and to compare our results with theoretical predictions”. Gabriele Ferrari, University of Trento, added that the results from this study, recently published in the latest issue of Nature Physics, are highly innovative. This discovery is a first step towards the validation of theories which were only on paper, and paves the road to new lines of research in the field of biochemistry and quantum computation.