Conclusive Experimental Demonstration of One-Way Einstein-Podolsky-Rosen Steering

Abstract

Einstein-Podolsky-Rosen steering is a quantum phenomenon wherein one party influences, or steers, the state of a distant party's particle beyond what could be achieved with a separable state, by making measurements on one-half of an entangled state. This type of quantum nonlocality stands out through its asymmetric setting and even allows for cases where one party can steer the other but where the reverse is not true. A series of experiments have demonstrated one-way steering in the past, but all were based on significant limiting assumptions. These consisted either of restrictions on the type of allowed measurements or of assumptions about the quantum state at hand, by mapping to a specific family of states and analyzing the ideal target state rather than the real experimental state. Here, we present the first experimental demonstration of one-way steering free of such assumptions. We achieve this using a new sufficient condition for nonsteerability and, although not required by our analysis, using a novel source of extremely high-quality photonic Werner states.

Network Quantum Steering

“…This follows from Ref. [39], as for any state ρ AB unsteerable from Alice to Bob, we have that 1 A ⊗ Ω B ½ρ AB is also unsteerable from A to B, for any channel Ω [40]. Note also that in the context of entanglement swapping, projecting two copies of ρ DEW ðη; ωÞ onto jψ − ihψ − j leads to ρ DEW ðη; ω 2 Þ (with probability η 2 =4), that is to a DEW state with squared visibility (see Supplemental Material Sec.…”

Quantum steering for continuous variable in de Sitter space

“…For the foregoing reasons, quantum steerability has recently attracted increasing interest both from theoretical [8][9][10][11][12][13][14][15][16][17] and experimental [18][19][20][21][22] perspectives. Most recently, Tischler et.al reported an experimental demonstration of unidirectional steering, which is free either of the restrictions on the type of allowed measurements or of assumptions about the quantum state at hand [23].…”

Necessary conditions for steerability of two qubits from consideration of local operations

“…As such, a characterization of the set of states which are able to demonstrate steering could be of great use for future quantum technologies. * travis.baker@griffithuni.edu.au Moreover, the question of proving non-steerability with respect to a given set of measurements is important in studying the phenomena of one-way steering [5][6][7][8][9][10], hidden steering [11], and joint measurability [12][13][14].…”