973 research outputs found
An All-But-One Entropic Uncertainty Relation, and Application to Password-based Identification
Entropic uncertainty relations are quantitative characterizations of
Heisenberg's uncertainty principle, which make use of an entropy measure to
quantify uncertainty. In quantum cryptography, they are often used as
convenient tools in security proofs. We propose a new entropic uncertainty
relation. It is the first such uncertainty relation that lower bounds the
uncertainty in the measurement outcome for all but one choice for the
measurement from an arbitrarily large (but specifically chosen) set of possible
measurements, and, at the same time, uses the min-entropy as entropy measure,
rather than the Shannon entropy. This makes it especially suited for quantum
cryptography. As application, we propose a new quantum identification scheme in
the bounded quantum storage model. It makes use of our new uncertainty relation
at the core of its security proof. In contrast to the original quantum
identification scheme proposed by Damg{\aa}rd et al., our new scheme also
offers some security in case the bounded quantum storage assumption fails hold.
Specifically, our scheme remains secure against an adversary that has unbounded
storage capabilities but is restricted to non-adaptive single-qubit operations.
The scheme by Damg{\aa}rd et al., on the other hand, completely breaks down
under such an attack.Comment: 33 pages, v
The demand for health: differences between the native Dutch and immigrants in the Netherlands
This paper estimates the demand for health by using a health capital model for different population groups (native Dutch, Surinamese/Antillean, Moroccan, and Turkish) in the Netherlands. Also the effect of overweight on health utility is investigated. We found a decrease in the demand for health for age, overweight, and smoking, we found an increase in the demand for health for level of education and marital status. The analyses show a strong effect of gender. Being female in all groups is negatively related to health utility. Turkish and Moroccan ethnicity is negatively related to health status.demand for health, health production, ethnicity, overweight, food habits, Health Economics and Policy, C24, C25, I10, I12,
The effects of food habits and socioeconomic status on overweight. Differences between the native Dutch and immigrants in the Netherlands
Overweight is a worldwide growing epidemic. The Netherlands is among the countries with the highest prevalence for overweight, together with the USA, UK, and Germany. This paper investigates differences in overweight between native Dutch and three immigrant groups in the Netherlands, and the effects of food habits and socioeconomic status on overweight. The results show that all immigrant groups have a higher prevalence for overweight than the Dutch, apart from Moroccans. Males are overweight more frequently than females. Takeaway food, eating out, and fresh vegetables decrease BMI, while convenience food, ready-to-eat meals, and delivery food (in some cases) increase BMI. In all groups, BMI increases with age. For Surinamese/Antilleans and Turks BMI increases with children living at home, whereas for native Dutch BMI decreases with children living at home. The national health expenditures due to overweight is 200 million to 4 billion Euro per year, which is 1 to 5 percent of the national health expenditures. The government and health insurance companies should try to prevent overweight and encourage healthy behavior.overweight, ethnicity, food habits, Food Consumption/Nutrition/Food Safety, C20, D12, I12,
Entropic uncertainty relations and entanglement
We discuss the relationship between entropic uncertainty relations and
entanglement. We present two methods for deriving separability criteria in
terms of entropic uncertainty relations. Especially we show how any entropic
uncertainty relation on one part of the system results in a separability
condition on the composite system. We investigate the resulting criteria using
the Tsallis entropy for two and three qubits.Comment: 8 pages, 3 figures, v2: small change
Quantum Zeno effect in the Cooper-pair transport through a double-island Josephson system
Motivated by recent experiments, we analyze transport of Cooper pairs through
a double-island Josephson qubit. At low bias in a certain range of gate
voltages coherent superpositions of charge states play a crucial role. Analysis
of the evolution of the density matrix allows us to cover a wide range of
parameters, incl. situations with degenerate levels, when dissipation strongly
affects the coherent eigenstates. At high noise levels the so-called Zeno
effect can be observed, which slows down the transport. Our analysis explains
certain features of the I-V curves, in particular the visibility and shape of
resonant peaks and lines
Long spin relaxation times in wafer scale epitaxial graphene on SiC(0001)
We developed an easy, upscalable process to prepare lateral spin-valve
devices on epitaxially grown monolayer graphene on SiC(0001) and perform
nonlocal spin transport measurements. We observe the longest spin relaxation
times tau_S in monolayer graphene, while the spin diffusion coefficient D_S is
strongly reduced compared to typical results on exfoliated graphene. The
increase of tau_S is probably related to the changed substrate, while the cause
for the small value of D_S remains an open question.Comment: 16 pages, 3 figures, 1 tabl
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