The structure of degradable quantum channels

Degradable quantum channels are among the only channels whose quantum and private classical capacities are known. As such, determining the structure of these channels is a pressing open question in quantum information theory. We give a comprehensive review of what is currently known about the structure of degradable quantum channels, including a number of new results as well as alternate proofs of some known results. In the case of qubits, we provide a complete characterization of all degradable channels with two dimensional output, give a new proof that a qubit channel with two Kraus operators is either degradable or anti-degradable and present a complete description of anti-degradable unital qubit channels with a new proof. For higher output dimensions we explore the relationship between the output and environment dimensions ($d_B$ and $d_E$ respectively) of degradable channels. For several broad classes of channels we show that they can be modeled with a environment that is "small" in the sense $d_E \leq d_B$. Perhaps surprisingly, we also present examples of degradable channels with ``large'' environments, in the sense that the minimal dimension $d_E > d_B$. Indeed, one can have $d_E > \tfrac{1}{4} d_B^2$. In the case of channels with diagonal Kraus operators, we describe the subclass which are complements of entanglement breaking channels. We also obtain a number of results for channels in the convex hull of conjugations with generalized Pauli matrices. However, a number of open questions remain about these channels and the more general case of random unitary channels.Comment: 42 pages, 3 figures, Web and paper abstract differ; (v2 contains only minor typo corrections

Having a Conversation About Health Care Wishes and Goals in Vermont

Research has shown that people think talking with family and friends about end-of-life care is important, but they do not actually have this conversation. The majority of adults do not have any form of advance care planning in place. In the state of Vermont if you are 18 years of age or older there is no default person to make decisions for you (such as a spouse or next of kin) in the event that you would be unable to do so, which can result in a complicated ethical dilemma. The goal of this project is to improve conversation rates between patients and their friends and families about their health care wishes and goals.https://scholarworks.uvm.edu/fmclerk/1347/thumbnail.jp

New method forms bond line free of voids

A new bonding method using vacuum, pressure and heat, which produces a bond line free of voids, is described. This method is very successful in bonding ablation shields to a magnesium structural component in simulated reentry tests involving great heat and air turbulence

Sensory Transduction and Subjective Experience: Expression of eight genes in three senses suggests a radical model of consciousness

Recent research into whole genome mapping of the mouse brain has made possible direct investigation of the brain expression of unusual genes. A search of the Allen Brain Atlas database has provided genetic and neuro-anatomical evidence for widespread specific expression in the brain of eight genes specific to sensory transduction, in vision, hearing and touch. A novel biophysical model is proposed for the function of these proteins, in generating the internal model of experiential reality

Presumptuous aim attribution, conformity, and the ethics of artificial social cognition

Imagine you are casually browsing an online bookstore, looking for an interesting novel. Suppose the store predicts you will want to buy a particular novel: the one most chosen by people of your same age, gender, location, and occupational status. The store recommends the book, it appeals to you, and so you choose it. Central to this scenario is an automated prediction of what you desire. This article raises moral concerns about such predictions. More generally, this article examines the ethics of artificial social cognition—the ethical dimensions of attribution of mental states to humans by artificial systems. The focus is presumptuous aim attributions, which are defined here as aim attributions based crucially on the premise that the person in question will have aims like superficially similar people. Several everyday examples demonstrate that this sort of presumptuousness is already a familiar moral concern. The scope of this moral concern is extended by new technologies. In particular, recommender systems based on collaborative filtering are now commonly used to automatically recommend products and information to humans. Examination of these systems demonstrates that they naturally attribute aims presumptuously. This article presents two reservations about the widespread adoption of such systems. First, the severity of our antecedent moral concern about presumptuousness increases when aim attribution processes are automated and accelerated. Second, a foreseeable consequence of reliance on these systems is an unwarranted inducement of interpersonal conformity