PURPOSE to examine the combined effect of cohabitation status and social participation, respectively, and socioeconomic position on onset of mobility limitations in a prospective study among older Danes. DESIGN AND METHODS logistic regression analyses with combined exposure variables were performed in a study population of 2,839 older men and women from the Danish Intervention Study on Preven...

The polynomial method and Ambainis’s lower bound method are two main quantum lower bound techniques. Recently Ambainis showed that the polynomial method is not tight. The present paper aims at studying the limitation of Ambainis’s lower bounds. We first give a generalization of the three known Ambainis’s lower bound theorems. Then it is shown that all these four Ambainis’s lower bounds have an ...

We show a simple example of a secret sharing scheme encoding classical secret to quantum shares that can realize an access structure impossible by classical information processing with limitation on the size of each share. The example is based on quantum stabilizer codes.

Noise in optical telecommunication fibers is an important limitation on optical quantum data transmission. Unfortunately, the classically successful amplifiers cannot be used in quantum communication because of the no-cloning theorem. We propose a simple method to reduce quantum noise: the insertion of phase shifters and/or beam splitters at regular distance intervals into a fiber. We analyze i...

We devise powerful algorithms based on differential evolution for adaptive many-particle quantum metrology. Our new approach delivers adaptive quantum metrology policies for feedback control that are orders-of-magnitude more efficient and surpass the few-dozen-particle limitation arising in methods based on particle-swarm optimization. We apply our method to the binary-decision-tree model for q...

The quantum internet holds promise for achieving quantum communication-such as quantum teleportation and quantum key distribution (QKD)-freely between any clients all over the globe, as well as for the simulation of the evolution of quantum many-body systems. The most primitive function of the quantum internet is to provide quantum entanglement or a secret key to two points efficiently, by usin...

The slow bimolecular recombination that drives three-dimensional lead-halide perovskites' outstanding photovoltaic performance is conversely a fundamental limitation for electroluminescence. Under electroluminescence working conditions with typical charge densities lower than 1015 cm-3, defect-states trapping in three-dimensional perovskites competes effectively with the bimolecular radiative r...

in this paper, based on the coupled-mode and carrier rate equations, a dynamic model and numerical analysis of a multi quantum well (mqw) chirped distributed feedback semiconductor optical amplifier (dfb-soa)  all-optical flip-flop is precisely derived. we have analyzed the effects of strains of qw and mqw and cross phase modulation (xpm) on the dynamic response, and rise and fall times of the ...

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