Experimental realisation of 2 out of 4 quantum state elimination

Author / Creator

Bristol Quantum Information Technologies Workshop (2021)

Conferences

Bristol Quantum Information Technologies Workshop Poster session 1 & networking on Gathertown (2021)

Available as

Online

Summary

Quantum measurements lie at the heart of experimental quantum science and quantum information processing. Traditionally, these measurements take the form of projecting a state intoa certain basis w...

Quantum measurements lie at the heart of experimental quantum science and quantum information processing. Traditionally, these measurements take the form of projecting a state intoa certain basis which tells us information about what the state is. Quantum state elimination (QSE) has recently garnered attention as an alternative approach where the outcomes tells uswhat the state is not. QSE plays a role in foundational physics about what is the nature ofa quantum state established by Pusey, Barrett and Rudolph (PBR). Recently, J. Crickmore, etal (Phys. Rev. Res., 2, 013256) proposed a new protocol for two-out-of-four state elimination extending QSE to a multiqubit setting. Specifically, the authors introduced a non-trivial set off our states that cannot be resolved by projective measurements on each qubit, instead requiring entangled measurement operators. These entangled measurements take the form of POVMs. States are encoded into pathmodes while the POVM is implemented interferometrically. We employ a beam displacer type interferometry for passive path mode stability. Specific detection events correspond to a POVM element which, along with a certain prepared state, results in two-out-of-four states being eliminated. Beyond being a proof of principle demonstration, useful quantum communication andcryptography schemes will be investigated.

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