Underground Italian lab searches for signals of quantum gravity
Dec 16, 2022
For decades physicists have been hunting for a quantum-gravity model that would unify quantum physics, the laws that govern the very small, and gravity. One major obstacle has been the difficulty in testing the predictions of candidate models experimentally. But some of the models predict an effect that can be probed in the lab: a very small violation of a fundamental quantum tenet called the Pauli exclusion principle, which determines, for instance, how electrons are arranged in atoms. An FQxI-funded project carried out at the INFN underground laboratories under the Gran Sasso mountains in Italy, has been searching for signs of radiation produced by such a violation, in the form of atomic transitions forbidden by the Pauli exclusion principle. In two papers appearing in the journals Physical Review Letters (published on 19th September 2022) and Physical Review D (accepted for publication on 7th December 2022) the team reports that no evidence of violation has been found, thus far, ruling out some quantum-gravity models.
Mini-engine exploits noise to convert information into fuel
Nov 14, 2022
Too much background noise is usually guaranteed to disrupt work. But FQxI-funded physicists have developed a micro-scale engine–made from a glass bead–that can not only withstand the distracting influence of noise, but can harness it to run efficiently. Their experiment is reported in the journal Physical Review Letters and was selected by the journal as a research highlight.
Master equation to boost quantum technologies
Aug 26, 2022
As the size of modern technology shrinks down to the nanoscale, weird quantum effects–such as quantum tunneling, superposition, and entanglement–become prominent. This opens the door to a new era of quantum technologies, where quantum effects can be exploited. Many everyday technologies make use of feedback control routinely; an important example is the pacemaker, which must monitor the user’s heartbeat and apply electrical signals to control it, only when needed. But physicists do not yet have an equivalent understanding of feedback control at the quantum level. Now, FQxI-funded physicists have developed a “master equation” that will help engineers understand feedback at the quantum scale. Their results are published in the journal Physical Review Letters.
A ‘beyond-quantum’ equivalence principle for superposition and entanglement
May 1, 2022
The physics of the microrealm involves two famous and bizarre concepts: The first is that prior to observation, it is impossible to know with certainty the outcome of a measurement on a particle; rather the particle exists in a ‘superposition’ encompassing multiple mutually exclusive states. So a particle can be in two or more places at the same time, and you can only calculate the probability of finding it in a certain location when you look. The second involves ‘entanglement,’ the spooky link that can unite two objects, no matter how far they are separated. Both superposition and entanglement are described mathematically by quantum theory. But many physicists believe that the ultimate theory of reality may lie beyond quantum theory. Now, a team of physicists and mathematicians has discovered a new connection between these two weird properties that does not assume that quantum theory is correct. Their FQxI-funded study appears in Physical Review Letters and has been selected as an Editors’ Suggestion by the journal.
Is the ‘fine-tuned universe’ an illusion?
Feb 7, 2022
For decades physicists have been perplexed about why our cosmos appears to have been precisely tuned to foster intelligent life. It is widely thought that if the values of certain physical parameters, such as the masses of elementary particles, were tweaked, even slightly, it would have prevented the formation of the components necessary for life in the universe — including planets, stars, and galaxies. But recent studies, detailed in a new report by the Foundational Questions Institute, FQxI, propose that intelligent life could have evolved under drastically different physical conditions. The claim undermines a major argument in support of the existence of a multiverse of parallel universes.