Physicists Find No Material Can Be Perfectly Transparent
Researchers show that quantum effects cause even the clearest light-bending materials to absorb some light.
Updated on Nov. 7, 2026 in Physics
Theoretical physicists calculated that no light-bending material can ever be fully transparent, as photons lose energy to atomic nuclei through a quantum process. The findings were posted as an arXiv preprint on October 8.
Why it matters
The result sets a physical limit on how transparent optical materials can become, which bears on the design of lenses and other light-manipulating devices. Researchers expect other materials to follow similar rules to the superfluid model used in the analysis.
The analysis is a theoretical calculation posted as a preprint, and a perfect superfluid would transmit light across roughly Earth's diameter before fading. How closely real materials such as Ivan Smalyukh's gels match this limit remains unverified by independent measurement.
The players
Ivan Smalyukh
Ivan Smalyukh is a physicist at the University of Colorado Boulder whose lab developed gels that bend light almost as little as air does.
Borna Salehian
Borna Salehian is a physicist at ETH Zurich who was not involved with the project and commented on the findings.
Angelo Esposito
Angelo Esposito is a physicist who realized the same energy-loss process that could detect dark photons in superfluid helium would also affect normal photons.
The details
Light is lost when a photon transfers energy to an atomic nucleus, producing a quantum mechanical sound wave, and repeated interactions gradually drain its energy until it becomes undetectable. Ivan Smalyukh's lab at the University of Colorado Boulder developed gels that bend light almost as little as air does, while the physicists' superfluid model describes frictionless flow that is coordinated by quantum mechanics.
Timeline
October 8, 2026: Physicists post their findings as an arXiv preprint.
November 7, 2026: Scientific American publishes an article on the work.
The Big Picture
The work builds on the known clarity of liquid helium, which absorbs x-rays yet has shown no measured effect on visible light. It extends superfluid research by showing that the energy-loss process developed for detecting dark photons also applies to normal photons.
Clearer optical materials depend on these quantum limits, so designers of lenses and light-based tools must account for the small amount of light every transparent material absorbs. Practical transparency will be bounded by these physical constraints regardless of how carefully a material is made.
The takeaway
No material can transmit light perfectly, because quantum interactions with atomic nuclei always drain a small amount of energy from photons. Designers of optical systems should treat this physical limit as a fixed boundary when planning transparent components.
Further reading
Explore more on Physics to see how quantum effects shape the behavior of light and matter.
More information
Read the physicists' preprint on transparent materials posted on arXiv.org.
Source note: This article includes information reported by Scientific American.
