Communicating over adversarial quantum channels using quantum list codes

We study quantum communication in the presence of adversarial noise. In this setting, communicating with perfect fidelity requires using a quantum code of bounded minimum distance, for which the best known rates are given by the quantum Gilbert-Varshamov (QGV) bound. By asking only for arbitrarily high fidelity and allowing the sender and reciever to use a secret key with length logarithmic in the number of qubits sent, we achieve a dramatic improvement over the QGV rates. In fact, we find protocols that achieve arbitrarily high fidelity at noise levels for which perfect fidelity is impossible. To achieve such communication rates, we introduce fully quantum list codes, which may be of independent interest.Comment: 6 pages. Discussion expanded and more details provided in proofs. Far less unclear than previous versio

Maximal Privacy Without Coherence

Privacy lies at the fundament of quantum mechanics. A coherently transmitted quantum state is inherently private. Remarkably, coherent quantum communication is not a prerequisite for privacy: there are quantum channels that are too noisy to transmit any quantum information reliably that can nevertheless send private classical information. Here, we ask how much private classical information a channel can transmit if it has little quantum capacity. We present a class of channels N_d with input dimension d^2, quantum capacity Q(N_d) <= 1, and private capacity P(N_d) = log d. These channels asymptotically saturate an interesting inequality P(N) <= (log d_A + Q(N))/2 for any channel N with input dimension d_A, and capture the essence of privacy stripped of the confounding influence of coherence.Comment: 6 pages. Proof of Eq.(13) slightly revise

The Prisoners in German Concentration Camps

The term Holocaust comes from the Hebrew word olah, meaning burnt sacrifice. In the Greek translation of the Old Testament, this word became holokauston. Today, the word Holocaust is used to denote the Nazi persecution of the Jews, resulting in the extermination of some six million men, women, and children in concentration and extermination camps. The term should bring to mind horrible images of torture, death, and destruction. Yet, in most cases, this does not happen. Although many people are familiar with The Diary of Anne Frank, The Hiding Place, and The Holocaust, even in today\u27s highly educated society, there is an appalling lack of knowledge concerning this tragic event. Some people claim that the Holocaust never existed. Arthur Butz, in his book The Hoax of the Twentieth Century, said that there were no records of the Holocause, therefore it could never have occurred. Dozens and dozens of pamphlets were circulated after the television showing of Gerald Green\u27s book, The Holocaust, warning people against this Jewish propaganda. They say that the Holocause was and is a fraud perpetrated by the Jews. How should one react to such statements? Elie Wiesel answers this in an article written for Social Education magazine.... Wiesel goes on to say in the article that anyone not involved in keeping those memories alive is an accomplice to the killers, and, in this writer\u27s opinion, he is correct. Studying such an event forces one to try and understand how human beings could allow such a tragedy to transpire. This paper is designed to be informative: to answer questions about what led to the event we call the Holocaust, to give the facts about what happened in the camps themselves, to explain how life in the camps affected the prisoners psychologically, and to tell some of what has happened to them since the Holocaust ended

Designing Backwards from College to High School: Practical Insights about Teaching Threshold Concepts

“Scholarship is a Conversation,” involves mastering disciplinary ways of thinking and communicating including using nuances in syntax, specialized vocabulary and subject-appropriate evidence to convey ideas in an appropriate medium or genre, shaped for a particular audience and context. We asked ourselves: What developmentally appropriate sequence could we craft to teach this concept that might serve as a model for other teaching librarians across institutions? How could students learn a rhetorically-nuanced inquiry process that would enable them to weigh and weave source ideas into a multicolored tapestry in their own voices? We will share our initial work to introduce “Scholarship is a Conversation” in the context of the humanities, the sciences, and the social sciences and invite you to think about ways to translate this to your own teaching

Can closed timelike curves or nonlinear quantum mechanics improve quantum state discrimination or help solve hard problems?

We study the power of closed timelike curves (CTCs) and other nonlinear extensions of quantum mechanics for distinguishing nonorthogonal states and speeding up hard computations. If a CTC-assisted computer is presented with a labeled mixture of states to be distinguished--the most natural formulation--we show that the CTC is of no use. The apparent contradiction with recent claims that CTC-assisted computers can perfectly distinguish nonorthogonal states is resolved by noting that CTC-assisted evolution is nonlinear, so the output of such a computer on a mixture of inputs is not a convex combination of its output on the mixture's pure components. Similarly, it is not clear that CTC assistance or nonlinear evolution help solve hard problems if computation is defined as we recommend, as correctly evaluating a function on a labeled mixture of orthogonal inputs.Comment: 4 pages, 3 figures. Final version. Added several references, updated discussion and introduction. Figure 1(b) very much enhance

Typical entanglement of stabilizer states

How entangled is a randomly chosen bipartite stabilizer state? We show that if the number of qubits each party holds is large the state will be close to maximally entangled with probability exponentially close to one. We provide a similar tight characterization of the entanglement present in the maximally mixed state of a randomly chosen stabilizer code. Finally, we show that typically very few GHZ states can be extracted from a random multipartite stabilizer state via local unitary operations. Our main tool is a new concentration inequality which bounds deviations from the mean of random variables which are naturally defined on the Clifford group.Comment: Final version, to appear in PRA. 11 pages, 1 figur

A qualitative assessment of women’s sourcing and appraisal of maternal nutritional information: a pilot study

A qualitative assessment of women’s sourcing and appraisal of maternal nutritional information: a pilot study. By M. Hanson, D. Smith and R. Gregg, Department of Health Professionals, Manchester Metropolitan University, 53 Bonsall Street, Manchester, M15 6GX Susceptibility to obesity and certain non-communicable diseases (NCDs) stem from pre-conception and foetal development in-utero(1). There is also a growing body of evidence to suggest that diet quality (DQ) is significantly important throughout pregnancy, irrespective of maternal BMI(2). However, healthcare professionals (HCPs) and guidelines from the National Institute for Health and Care Excellence (NICE) maintain focus on sustaining a normal BMI(3). This study aimed to assess where and how women source and appraise nutritional information during pregnancy, to understand further the nutritional needs of the mother, and the role of HCPs in providing nutritional support. Women were recruited via social media and from community maternity services. Four focus groups were carried out, and halted due to data saturation. In total, 13 participants were included (pregnant n=3, up to 12-months post-partum n=10). Focus groups were transcribed, subjected to thematic analysis and categorised into four central themes (Attitudes, Acquisition, Barriers and Knowledge) grounded in the theory, which were presented in a thematic map. Firstly, regarding the Attitudes reported by women, there was an awareness of supplementation requirements and “unsafe” foods to avoid during pregnancy, yet this was usually inaccurate. Beyond foods to avoid women reported higher intakes of “chocolate”, “cake” and “stodge”, as shown in figure 1. They saw this as compensation for having to avoid the “unsafe” foods as they felt there were few consequences beyond displeasing aesthetics. Secondly, Acquisition of nutrition information was both active (mainly internet) and passive (mainly HCPs, friends and family). Participants displayed self-confidence and an ‘expert opinion’ due to the accessibility of information on the internet. Women sought this information due to uncertainties and a feeling of unmet nutritional needs: one woman found that both her midwife and doctor could not advise on non-dairy sources of calcium, as shown in figure 2. Thirdly, Barriers included the trustworthiness of differing sources: most women reported difficulties in appraising the available information, as shown in figure 3. Moreover, women reported HCPs made the assumption that women were already knowledgeable about the constituents of a “healthy diet” and therefore did not explain further, resulting in confusion and a lack of knowledge among the participants. Finally, Knowledge surrounding guidelines and the importance of DQ in this group was found to be poor, as shown in figure 4 and participants reported that HCPs did not follow-up the initial weigh-in with any further weigh-ins, nutritional support or guidance, irrespective of their BMI, despite NICE stipulating all three for overweight/obese expectant mothers. In conclusion, the themes presented are in support of wider research demonstrating both the need and difficulty in providing detailed, individualised nutritional support for expectant mothers. Moreover, a revision of NICE guidelines may be required to recognise not only maternal BMI but the importance of DQ and methods for safe weight loss throughout pregnancy as well, to mirror the current literature(2) (3). With the hope to reduce NCD prevalence in the future; in line with the World Health Organsiation Agenda for Sustainable Development. 1. Baird J, Jacob C et al. Healthcare. 2017;5(1):14. 2. Shapiro A, Kaar J et al. IJO. 2016;40(7):1056-1062. 3. Brown A, Avery A. J Hum Nutr Diet. 2012;25(4):378-387

Obstetrician-assessed maternal health at pregnancy predicts offspring future health

Background: We aimed to examine the association between obstetrician assessment of maternal physical health at the time of pregnancy and offspring cardiovascular disease risk.&lt;p&gt;&lt;/p&gt; Methods and Principal Findings: We examined this association in a birth cohort of 11,106 individuals, with 245,000 person years of follow-up. We were concerned that any associations might be explained by residual confounding, particularly by family socioeconomic position. In order to explore this we used multivariable regression models in which we adjusted for a range of indicators of socioeconomic position and we explored the specificity of the association. Specificity of association was explored by examining associations with other health related outcomes. Maternal physical health was associated with cardiovascular disease: adjusted (socioeconomic position, complications of pregnancy, birthweight and childhood growth at mean age 5) hazard ratio comparing those described as having poor or very poor health at the time of pregnancy to those with good or very good health was 1.55 (95%CI: 1.05, 2.28) for coronary heart disease, 1.91 (95%CI: 0.99, 3.67) for stroke and 1.57 (95%CI: 1.13, 2.18) for either coronary heart disease or stroke. However, this association was not specific. There were strong associations for other outcomes that are known to be related to socioeconomic position (3.61 (95%CI: 1.04, 12.55) for lung cancer and 1.28 (95%CI:1.03, 1.58) for unintentional injury), but not for breast cancer (1.10 (95%CI:0.48, 2.53)).&lt;p&gt;&lt;/p&gt; Conclusions and Significance: These findings demonstrate that a simple assessment of physical health (based on the appearance of eyes, skin, hair and teeth) of mothers at the time of pregnancy is a strong indicator of the future health risk of their offspring for common conditions that are associated with poor socioeconomic position and unhealthy behaviours. They do not support a specific biological link between maternal health across her life course and future risk of cardiovascular disease in her offspring.&lt;p&gt;&lt;/p&gt