6 research outputs found
Interfacing a quantum dot spin with a photonic circuit
A scalable optical quantum information processor is likely to be a waveguide
circuit with integrated sources, detectors, and either deterministic
quantum-logic or quantum memory elements. With microsecond coherence times,
ultrafast coherent control, and lifetime-limited transitions, semiconductor
quantum-dot spins are a natural choice for the static qubits. However their
integration with flying photonic qubits requires an on-chip spin-photon
interface, which presents a fundamental problem: the spin-state is measured and
controlled via circularly-polarised photons, but waveguides support only linear
polarisation. We demonstrate here a solution based on two orthogonal photonic
nanowires, in which the spin-state is mapped to a path-encoded photon, thus
providing a blue-print for a scalable spin-photon network. Furthermore, for
some devices we observe that the circular polarisation state is directly mapped
to orthogonal nanowires. This result, which is physically surprising for a
non-chiral structure, is shown to be related to the nano-positioning of the
quantum-dot with respect to the photonic circuit
ARTICLE DNA methylation signatures link prenatal famine exposure to growth and metabolism
Periconceptional diet may persistently influence DNA methylation levels with phenotypic consequences. However, a comprehensive assessment of the characteristics of prenatal malnutrition-associated differentially methylated regions (P-DMRs) is lacking in humans. Here we report on a genome-scale analysis of differential DNA methylation in whole blood after periconceptional exposure to famine during the Dutch Hunger Winter. We show that P-DMRs preferentially occur at regulatory regions, are characterized by intermediate levels of DNA methylation and map to genes enriched for differential expression during early development. Validation and further exploratory analysis of six P-DMRs highlight the critical role of gestational timing. Interestingly, differential methylation of the P-DMRs extends along pathways related to growth and metabolism. P-DMRs located in INSR and CPT1A have enhancer activity in vitro and differential methylation is associated with birth weight and serum LDL cholesterol. Epigenetic modulation of pathways by prenatal malnutrition may promote an adverse metabolic phenotype in later life