bell theorem

quantum states

multipartite entanglement

quantum state

entanglement

quantum mechanical

remote state preparation

quantum discord

entangled states

bell inequalities

Physical review

We give strong analytic and numerical evidence that, under mild measurement\nassumptions, two qubits cannot both be recycled to generate Bell nonlocality\nbetween multiple independent observers on each side. This is surprising, as\nunder the same assumptions it is possible to recycle just one of the qubits an\narbitrarily large number of times [P. J. Brown and R. Colbeck, Phys. Rev. Lett.\n125, 090401 (2020)]. We derive corresponding 'one-sided monogamy relations'\nthat rule out two-sided recycling for a wide range of parameters, based on a\ngeneral tradeoff relation between the strengths and maximum reversibilities of\nqubit measurements. We also show if the assumptions are relaxed to allow\nsufficiently biased measurement selections, then there is a narrow range of\nmeasurement strengths that allows two-sided recycling for two observers on each\nside, and propose an experimental test. Our methods may be readily applied to\nother types of quantum correlations, such as steering and entanglement, and\nhence to general information protocols involving sequential measurements.\n

Limitations on sharing Bell nonlocality between sequential pairs of observers