Instead, the first hint of the boson was inspired by studies of superconductors – a special class of metals that, when cooled to very low temperatures, allow electrons to move without resistance. The discovery of the Higgs boson verified the Standard Model, which predicted that particles gain mass by passing through a field that slows down their movement through the vacuum of space. Now a team of physicists has brought that work full circle, by reporting the first-ever observations of the Higgs mode in superconducting materials.
And they didn't need an $8 billion machine, they did it in a regular laboratory at relatively low cost.
“Just as the CERN experiments revealed the existence of the Higgs boson in a high-energy accelerator environment, we have now revealed a Higgs boson analog in superconductors,” says Prof. Aviad Frydman, a member of Bar-Ilan University’s Department of Physic. “Ironically, while the discussion about this ‘missing link’ in the Standard Model was inspired by superconductor theory, the Higgs mode was never actually observed in superconductors because of technical difficulties – difficulties that we’ve managed to overcome.”
In their paper, Frydman and his colleagues describe a new method for conducting Higgs physics experiments. “The high energy required to excite a Higgs mode in superconductors tends to break apart the electron pairs serving as this type of material’s basic charge. This causes rapid decay into particle-hole pairs, and suppresses the material’s superconducting nature. We solved this problem by using disordered and ultra-thin superconducting films of Niobium Nitrite (NbN) and Indium Oxide (InO) near the superconductor-insulator critical point – a state in which recent theory predicted the rapid decay of the Higgs would no longer occur. This created the conditions to excite a Higgs mode at relatively low energies.”
According to Frydman, observation of the Higgs mechanism in superconductors is significant because it reveals how a single type of physical process behaves under drastically different energy conditions.
“Exciting the Higgs mode in a particle accelerator requires enormous energy levels – measured in giga-electronvolts, or 109 eV,” Frydman says. “The parallel phenomenon in superconductors occurs on a different energy scale entirely – just one-thousandth of a single electronvolt. What’s exciting is to see how, even in these highly disparate systems, the same fundamental physics is at work.”
Moreover, the robust nature of the newly-observed Higgs mode in superconductors could make it easier for scientists to study the still-controversial “God particle” – the elusive “missing link” in the Standard Theory of particle physics believed responsible for imparting mass to all the matter in the universe.
Thanks to this new approach, they believe it may soon be possible to solve long-standing mysteries of fundamental physics, through experiments conducted on a laboratory tabletop.
Published in Nature Physics.