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Delft experiment closes two major loopholes in tests of entanglement

Aug 24, 2015

Ronald Hanson's team tests entangled electron spins in diamond defects 1.3 km apart, closing the detection and locality loopholes in a Bell test. The result is reported in an August 2015 preprint and published in Nature that October.

Why it matters

Tests of this kind can help certify quantum connections and secure communications without relying on trust in the devices' internal workings.

Ronald Hanson · Bas Hensen · QuTech

See it on the timeline

Physics Nobel goes to Aspect, Clauser and Zeilinger for entanglement experiments (Oct 4, 2022)

Sources (3)

arXiv (Hensen et al.) Experimental loophole-free violation of a Bell inequality using entangled electron spins separated by 1.3 km
Primary sourceAug 24, 2015

“Here we report on a Bell experiment that is free of any such additional assumption”
Nature Loophole-free Bell inequality violation using electron spins separated by 1.3 kilometres
Primary sourceOct 21, 2015

“Here we report a Bell experiment that is free of any such additional assumption and thus directly tests the principles underlying Bell’s inequality.”
Physics World Physicists claim 'loophole-free' Bell-violation experiment
Independent coverageSep 2, 2015

“Ronald Hanson and colleagues have eliminated the locality and detection loopholes in the same Bell violation experiment.”

Added Oct 19, 2026 · Updated Oct 24, 2026. Spotted an error? Tell us and we will review it.

Delft experiment closes two major loopholes in tests of entanglement

Why it matters

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