According to the ER=EPR hypothesis, entangled particles are connected by quantum wormholes. The work shows that if we allow part of a charged particle's electric field to leak into such a wormhole, it will change the hyperfine structure of a hydrogen atom. In the case of non-traversable wormholes, it also predicts a nonzero total effective charge for the atom. Comparing these predictions with high-precision measurements of hyperfine splitting and hydrogen neutrality yields strict constraints on the amplitude of the hypothetical effect. Precision atomic physics thus serves as a tool to test the fundamental connection between quantum information and spacetime geometry.
Two water droplets tremble in sync — because they're connected by a straw. So it is with entangled particles: their unity may be held together by a microscopic wormhole. Juan Maldacena and Leonard Susskind called this conjecture ER=EPR: Einstein-Rosen bridges (ER) equal the Einstein-Podolsky-Rosen paradox (EPR).
If such a wormhole exists, a charged particle could lose part of its electric field into the tunnel. For the simplest atom — hydrogen — this would result in a frequency shift of the famous 21 cm line, its 'radio voice'. Spectral analysis could detect a change of billionths of a percent. But more importantly: an impassable wormhole would lock away some charge inside, making the atom slightly charged.
Yet hydrogen is exceptionally neutral. Measurements give zero down to 10⁻²¹ of the electron charge — like looking for a single grain of sand on all the beaches of Earth.
Precision experiments within ordinary physics are valuable because they can test the boldest hypotheses about the geometry of the universe.
🎯 The 21 cm radio line is the voice of the universe's most abundant element. Using it, astronomers map invisible hydrogen and hunt for dark matter.
🎬 In 'Interstellar', wormholes are colossal portals between stars; this new work brings those bridges to the subatomic level, inside the hydrogen atom.