Empty space appears silent, but at the quantum level, it hums with faint, unavoidable noise. A team of international researchers has now found a way to harness that noise to strengthen superconductivity, the phenomenon in which a material conducts electric current with zero resistance.
In a new study, the team demonstrated that carefully engineered vacuum fluctuations can raise the superconducting transition temperature of niobium diselenide (NbSe₂). “This represents the first experimental observation of vacuum-fluctuation-enhanced superconductivity,” said study author Guanghui Cheng, a professor at the Chinese Academy of Sciences.
The finding suggests that empty space itself could become a new tool for manipulating quantum matter, joining a broader push to expand the limits of superconducting materials.
Turning the Quantum Vacuum Into a Control Knob
The central challenge is that vacuum fluctuations are normally far too weak to meaningfully influence the collective behaviour of a macroscopic material. Quantum mechanics dictates that even a system’s lowest-energy state retains unavoidable fluctuations in its fields, effects such as the Lamb shift and the Casimir effect have already confirmed these fluctuations are physically real, not merely theoretical.
The researchers set out to ask whether such fluctuations could instead be amplified and put to work controlling superconductivity. Their solution was a terahertz split-ring resonator, a structure engineered to confine and reshape electromagnetic fields. The team placed a six-layer NbSe₂ device inside this so-called dark cavity, creating a system in which the material’s electronic behaviour could interact directly with the cavity’s fluctuating electromagnetic modes.
