Measure the fine structure constant with your eyes !

Picture from Nair et al., Fine Structure Constant Defines Visual Transparency of Graphene, Science (2008).



Have you ever wondered about the hidden "cosmic code" of our universe? The fine structure constant, α, is a mind-bending number that’s captivated physicists for over a century. Introduced by Arnold Sommerfeld in 1916 to explain the hiperfine splitting of atomic spectra, α is a universal, dimensionless constant, representing an interplay of fundamental properties like the electron charge, Planck’s constant, and vacuum permittivity.



What’s amazing? Its inverse is eerily close to the number 137—a figure shrouded in scientific mystery and fascination.
A very interesting introduction to the fine structure constant can be found on the NIST american office of standards website at this address.

Measuring α usually requires sophisticated setups and advanced quantum effects, like the quantum Hall effect.

But what if I told you that a material could help you "see" this constant with your own eyes?

In a groundbreaking 2008 discovery, Nobel Laureates K.S. Novoselov and A. Geim found that a single layer of graphene absorbs exactly 2.3% of incoming light, a value connected to the fine structure constant via the irrational number π, namely π α ≈ 2.3%.
In fact, when you look at a single layer of graphene, you’re witnessing a direct, visible measurement of a fundamental constant of nature!
The precision of this result over a wide range of light frequencies is as close as you’ll get to nature performing quantum mechanics in front of you.

Take a closer look at the picture in panel (A): a circular spot of white light illuminates sample composed of air (leftmost part), a single layer graphene (center) and a bilayer graphene (rightmost part). While 100% of light passes through air, 97.7% passes through the central part (single layer graphene), and about 95% through the rightmost part (bilayer graphene).

The right panel B shows that, indeed, the opacity of graphene is 2.3% over a broad range of incoming photon wavelengths.

This real-life optical experiment mirrors the precision of atomic spectrometers, bringing theory and observation stunningly close.

Curious about how this all connects to quantum mechanics?

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Read this famous 1-page long paper cited more than 11000 times by clicking here (Require subscription to Science Journal)

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