Phase-modulated single-photon nonreciprocal transport and directional router in a waveguide-cavity-emitter system beyond the chiral coupling

We propose a potentially practical scheme for the controllable single-photon transport via waveguides which are coupled to a microcavity-emitter system. The microcavity-emitter system consists of a V-type three-level emitter and two or one single-mode microcavity. A driving field is used to drive a hyperfine transition between two upper excited states of the V-type three-level emitter. Beyond chiral coupling between waveguides and microcavity-emitter system, we show that the perfectly nonreciprocal single-photon transport in a single waveguide and the single-photon router with 100% routing probability in two waveguides can be achieved. Interesting enough, whether the nonreciprocal single-photon transport or the single-photon router can be switched periodically by adjusting the phase associated with microcavity-emitter coupling strength and the driving field. The complete physical explanation of the underlying mechanism is presented.

Lost photon enhances superresolution

Quantum imaging can beat classical resolution limits, imposed by the diffraction of light. In particular, it is known that one can reduce the image blurring and increase the achievable resolution by illuminating an object by entangled light and measuring coincidences of photons. If an n-photon entangled state is used and the nth-order correlation function is measured, the point-spread function (PSF) effectively becomes $$\sqrt{n}$$ n times narrower relatively to classical coherent imaging. Quite surprisingly, measuring n-photon correlations is not the best choice if an n-photon entangled state is available. We show that for measuring (n − 1)-photon coincidences (thus, ignoring one of the available photons), PSF can be made even narrower. This observation paves a way for a strong conditional resolution enhancement by registering one of the photons outside the imaging area. We analyze the conditions necessary for the resolution increase and propose a practical scheme, suitable for observation and exploitation of the effect.

DNA-based data storage via combinatorial assembly

Persistent data storage is the basis of all modern information systems. The long-term value and volume of data are growing at an accelerating rate and pushing extant storage systems to their limits. DNA offers exciting potential as a storage medium, but no practical scheme has been proposed to date that can scale beyond narrow-band write rates. Here, we demonstrate a combinatorial DNA data encoding scheme capable of megabits per second write speeds. The system relies on rapid, combinatorial assembly of multiple smaller DNA parts that are dispensed through inkjet printing. To demonstrate this approach, we wrote approximately 25 kB of information into DNA using our system and read the information back out with commercially available nanopore sequencing. Moreover, we demonstrate the ability to replicate and selectively access the information while it is in DNA, opening up the possibility of more sophisticated DNA computation.

Creating a Republican Executive

This chapter refers to the Articles of Confederation, which governed the new United States until the adoption of the Constitution in 1788. It elaborates how the national government had no executive branch, only a Congress and a tiny judiciary for maritime cases under the Articles of Confederation. It also talks about executive functions that were carried out by Congress, committees of Congress, or ministers appointed by and accountable to Congress. The chapter recounts the development of a new constitution that includes a real executive by the late 1780s. It mentions the framers, who had long experience in colonial legislatures, making it relatively easy for them to draft a practical scheme for the legislative branch.

Anonymous, Attribute Based, Decentralized, Secure, and Fair e-Donation

E-cash and cryptocurrency schemes have been a focus of applied cryptography for a long time. However, we acknowledge the continuing need for a cryptographic protocol that provides global scale, decentralized, secure, and fair delivery of donations. Such a protocol would replace central trusted entities (e.g., charity organizations) and guarantee the privacy of the involved parties (i.e., donors and recipients of the donations). In this work, we target this online donation problem and propose a practical solution for it. First, we propose a novel decentralized e-donation framework, along with its operational components and security definitions. Our framework relies on a public ledger that can be realized via a distributed blockchain. Second, we instantiate our e-donation framework with a practical scheme employing privacy-preserving cryptocurrencies and attributebased signatures. Third, we provide implementation results showing that our operations have feasible computation and communication costs. Finally, we prove the security of our e-donation scheme via formal reductions to the security of the underlying primitives.

Assessment of Dehydration in Children with Acute Gastroenteritis: A Review of International Guidelines

Background: Acute Gastroenteritis (AGE) is a major cause of presentation to hospital in children. Detection and classification of the degree of dehydration are vital for proper treatment. Methods: The authors reviewed six international guidelines on AGE in children. The aim was to equip clinicians working in a hospital setting with practical and readily applicable clinical handles to assist them in detecting and classifying dehydration. Results: Published international guidelines on AGE vary in their recommendations on the assessment of dehydration as well as their classification of dehydration severity. Nevertheless, a practical scheme utilizing a combination of these guidelines could be devised. Conclusion: In addition to the World Health Organization classification of dehydration in children, several clinical handles were suggested. Key words: acute gastroenteritis, children, dehydration, diarrhea