Experimental Quantum Key Distribution in an Indefinite Causal Order
Researchers posted an experimental demonstration of quantum key distribution in an indefinite causal order to arXiv. The work uses a quantum switch to create a superposition of causal orders for quantum channels instead of a fixed sequence.
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What this could mean
- 0–2 yearsPlausible
If the setup can be translated to telecom-wavelength components, this could enable head-to-head field tests of indefinite-causal-order QKD against ordered QKD on existing metropolitan fibre links within two years.
Photonic quantum-switch demonstrations already operate at single-photon level; converting to 1550 nm and integrating with standard QKD receivers is engineering work rather than requiring new physics.
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