Conclusive quantum steering with superconducting transition edge sensors

TL;DR

This paper demonstrates conclusive quantum steering using high-efficiency superconducting sensors, closing the detection loophole and enabling practical quantum communication applications.

Contribution

It presents the first conclusive quantum steering demonstration with superconducting transition edge sensors, achieving high detection efficiency and minimal measurement settings.

Findings

Achieved ~62% detection efficiency of entangled photons.

Violated a steering inequality by 48 standard deviations.

Closed the detection loophole in quantum steering experiments.

Abstract

Quantum steering allows two parties to verify shared entanglement even if one measurement device is untrusted. A conclusive demonstration of steering through the violation of a steering inequality is of considerable fundamental interest and opens up applications in quantum communication. To date all experimental tests with single photon states have relied on post-selection, allowing untrusted devices to cheat by hiding unfavourable events in losses. Here we close this "detection loophole" by combining a highly efficient source of entangled photon pairs with superconducting transition edge sensors. We achieve an unprecedented ~62% conditional detection efficiency of entangled photons and violate a steering inequality with the minimal number of measurement settings by 48 standard deviations. Our results provide a clear path to practical applications of steering and to a photonic loophole-free Bell test.