Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Conclusive quantum steering with superconducting transition-edge sensors



Devin H. Smith, Marcelo de Almeida, Gillett Geoff, Branciard Cyril, Allesandro Fedrizzi, Weinhold J. Till, Adriana Lita, Brice R. Calkins, Thomas Gerrits, Wiseman H, Sae Woo Nam, Andrew G. White


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 s.d.s. Our results provide a clear path to practical applications of steering and to a photonic loophole-free Bell test.
Physical Review Letters


steering, transition edge sensors, entanglement


Smith, D. , de Almeida, M. , Geoff, G. , Cyril, B. , Fedrizzi, A. , Till, W. , Lita, A. , Calkins, B. , Gerrits, T. , H, W. , Nam, S. and White, A. (2012), Conclusive quantum steering with superconducting transition-edge sensors, Physical Review Letters, [online],, (Accessed April 15, 2024)
Created January 9, 2012, Updated October 12, 2021