The concept of 'steering' was introduced in 1935 by Schrödinger as a generalization of the EPR (Einstein-Podolsky-Rosen) paradox. It has recently been formalized as a quantum-information task with ...arbitrary bipartite states and measurements, for which the existence of entanglement is necessary but not sufficient. Previous experiments in this area have been restricted to an approach that followed the original EPR argument in considering only two different measurement settings per side. Here we demonstrate experimentally that EPR-steering occurs for mixed entangled states that are Bell local (that is, that cannot possibly demonstrate Bell non-locality). Unlike the case of Bell inequalities, increasing the number of measurement settings beyond two-we use up to six-significantly increases the robustness of the EPR-steering phenomenon to noise.
The investigation of hyperspectral data from the Mars Reconnaissance Orbiter Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) and the Observatoire pour la Minéralogie, L'Eau, les Glaces ...et l'Activitié (OMEGA) on Mars Express has revealed an increasingly diverse suite of minerals present on the Martian surface. A revised set of 60 spectral parameters derived from corrected spectral reflectance at key wavelengths in CRISM targeted observations and designed to capture the known diversity of surface mineralogy on Mars is presented here as “summary products.” Some of the summary products have strong heritage to OMEGA spectral parameter calculations; this paper also presents newly derived parameters that highlight locations with more recently discovered spectral signatures. Type locations for the diversity of currently identified mineral spectral signatures have been compiled into a library presented in this work. Our analysis indicates that the revised set of summary products captures the known spectral diversity of the surface, and successfully highlights and differentiates between locations with differing spectral signatures. The revised spectral parameter calculations and related products provide a useful tool for scientific interpretation and for future mission landing site selection and operations.
Key Points
A revised set of 60 CRISM summary products captures Mars' spectral diversity
A library of 30 surface type spectra identified using CRISM is presented
New “browse products” demonstrate surface spectral variability
As commonly understood, the noise spectroscopy problem-characterizing the statistical properties of a noise process affecting a quantum system by measuring its response-is mathematically ill-posed, ...in the sense that no unique noise process leads to a set of responses unless extra assumptions are taken into account. Ad-hoc solutions assume an implicit structure, which is often never determined. Thus, it is unclear when the method will succeed or whether one should trust the solution obtained. Here, we propose to treat the problem from the point of view of statistical estimation theory. We develop a Bayesian solution to the problem which allows one to easily incorporate assumptions which render the problem solvable. We compare several numerical techniques for noise spectroscopy and find the Bayesian approach to be superior in many respects.
We show that when the speed of control is bounded, there is a widely applicable minimal-time control problem for which a coherent feedback protocol is optimal, and is faster than all ...measurement-based feedback protocols, where the latter are defined in a strict sense. The superiority of the coherent protocol is due to the fact that it can exploit a geodesic path in Hilbert space, a path that measurement-based protocols cannot follow.
We provide a new formulation of the Local Friendliness no-go theorem of Bong et al. Nat. Phys. 16, 1199 (2020) from fundamental causal principles, providing another perspective on how it puts ...strictly stronger bounds on quantum reality than Bell’s theorem. In particular, quantum causal models have been proposed as a way to maintain a peaceful coexistence between quantum mechanics and relativistic causality while respecting Leibniz’s methodological principle. This works for Bell’s theorem but does not work for the Local Friendliness no-go theorem, which considers an extended Wigner’s Friend scenario. More radical conceptual renewal is required; we suggest that cleaving to Leibniz’s principle requires extending relativity to events themselves.
This study examines the influence of backward-looking, reference-dependent decisions on forward-looking capital allocation investment choices across business units within a firm. Specifically, we ...develop an integrated behavioral framework for predicting how aspirations for business unit performance affect the efficiency of the internal capital allocation process. Results suggest that, contingent on dispersion in business unit performance and on firm slack, performance aspirations have pervasive effects; current performance above and below aspirations influences the efficiency of the allocation process. Given that prior examinations of aspiration-driven behavior have generally focused on changes in strategic organizational actions (e.g., R&D investment) without further considering the quality or appropriateness of such actions, this study contributes by also focusing on the appropriateness of capital allocations with clear implications for allocation efficiency.
Epidemiology is the study of the distribution of the occurrence and causes of disease. The non‐random distribution of the incidence of diseases, and factors associated with them, gives clues both to ...their causation and to possibilities of prevention. While an understanding of the biological processes that underpin associations can be useful in ascribing causality, it is not essential, nor necessary for developing preventive options. Epidemiology is essentially an observational discipline and therefore does not have the advantages of randomised experimental studies of avoiding confounding and other problems relating to measurement, in particular relating to diet and nutrition status. However, epidemiologic studies do have advantages of observing hard outcomes in typical populations over decades, which is valuable when exploring aetiology of chronic non‐communicable diseases. Nutritional epidemiology has been the main basis for understanding the causes and potential prevention of obesity, type 2 diabetes, cancer and cardiovascular diseases. When better integrated with in vitro and in vivo experimental data from humans and animals, nutritional epidemiology will remain a critical tool in the armoury for understanding the causes of disease, and offer targets for prevention.
Abstract Environmental factors influence breast cancer incidence and progression. High body mass index (BMI) is associated with increased risk of post-menopausal breast cancer and with poorer outcome ...in those with a history of breast cancer. High BMI is generally interpreted as excess adiposity (overweight or obesity) and the World Cancer Research Fund judged that the associations between BMI and incidence of breast cancer were due to body fatness. Although BMI is the most common measure used to characterise body composition, it cannot distinguish lean mass from fat mass, or characterise body fat distribution, and so individuals with the same BMI can have different body composition. In particular, the relation between BMI and lean or fat mass may differ between people with or without disease. The question therefore arises as to what aspect or aspects of body composition are causally linked to the poorer outcome of breast cancer patients with high BMI. This question is not addressed in the literature. Most studies have used BMI, without discussion of its shortcomings as a marker of body composition, leading to potentially important misinterpretation. In this article we review the different measurements used to characterise body composition in the literature, and how they relate to breast cancer risk and prognosis. Further research is required to better characterise the relation of body composition to breast cancer.
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