Test one to test many: a unified approach to quantum benchmarks

Quantum benchmarks are routinely used to validate the experimental demonstration of quantum information protocols. Many relevant protocols, however, involve an infinite set of input states, of which only a finite subset can be used to test the quality of the implementation. This is a problem, because the benchmark for the finitely many states used in the test can be higher than the original benchmark calculated for infinitely many states. This situation arises in the teleportation and storage of coherent states, for which the benchmark of 50% fidelity is commonly used in experiments, although finite sets of coherent states normally lead to higher benchmarks. Here we show that the average fidelity over all coherent states can be indirectly probed with a single setup, requiring only two-mode squeezing, a 50-50 beamsplitter, and homodyne detection. Our setup enables a rigorous experimental validation of quantum teleportation, storage, amplification, attenuation, and purification of noisy coherent states. More generally, we prove that every quantum benchmark can be tested by preparing a single entangled state and measuring a single observable.Comment: 18 pages, 6 figures, updated affiliation

Epidemiological studies on frailty and its associations with mortality, dementia, and polypharmacy

Frailty describes the status of decreased physiological reserves and increased vulnerability to adverse outcomes. As the aging population increases, frailty has become an important public health concern. However, longitudinal studies disclosing the associations of frailty with adverse outcomes over the life course are limited. In the thesis, we aimed at investigating the associations of frailty with mortality, dementia, and polypharmacy using three Swedish longitudinal studies of aging and comparing the characteristics of frailty between young and old adults using Swedish and UK data. Frailty was measured using the frailty index (FI). In Study Ⅰ, we assessed how frailty trajectories look by age at death and compared the predictive values of the level of frailty and the changes of frailty on mortality. We found that individuals who died before the age of 70 years had a steadily increasing trajectory, whereas in those individuals who died at older ages, frailty only increased after 75 years. The level of FI was a stronger predictor of mortality than the rate of change in FI in a longitudinal setting. In Study Ⅱ, we examined the association between baseline FI and the risk of subsequent dementia using a multivariate Cox model. Familial effects on frailty-dementia association were analyzed using a within-pair analysis. The age-varying effects of FI on dementia were also assessed. We found that the FI was associated with an increased risk of dementia independent of the Apolipoprotein E (APOE) ɛ4 carrier status. After adjusting for familial factors, no attenuation was found in dizygotic (DZ) and monozygotic (MZ) twins, indicating that shared environmental and genetic factors had no influence on the frailty-dementia association. The effect of the FI on dementia was constant after age 50. In Study Ⅲ, we investigated the differences in the prevalence, characteristics, and risk factors of early-life (aged <65) and late-life (aged ≥65) frailty using data from Sweden and UK. Comparison of the characteristics of early-life and late-life frailty was performed by collating the FI items (deficits) into domains and comparing the domain scores. We found that frailty is prevalent also in younger age groups, with pooled prevalence rates of 10.3% and 14.4% in individuals aged ≤ 55 and 55-65 years, respectively. Younger frail adults had higher scores in immunological, mental wellbeing, and pain-related domains, whereas older frail adults had higher scores in cardiometabolic, cancer, musculoskeletal, and sensory-related domains. Higher age, female sex, smoking, lower alcohol consumption, lower education, obesity, overweight, low income, and maternal smoking were similarly associated with the risk of early-life and late-life frailty. In Study Ⅳ, we focused on visualizing FI trajectories by polypharmacy and assessing the longitudinal associations between frailty and polypharmacy using a linear mixed model. We found that the long-term polypharmacy group had a higher FI trajectory than the transient and non-polypharmacy group. Polypharmacy was significantly associated with a higher risk of frailty, and the risk of being frail conferred by polypharmacy increased with age. In conclusion, frailty is a strong and independent predictor of adverse outcomes. Monitoring frailty and frailty progression is of great importance in middle-aged and older adults. Also, appropriate prescribing should be considered for middle-aged and old adults to prevent later frailty

The Happer's puzzle degeneracies and Yangian

We find operators distinguishing the degenerate states for the Hamiltonian $H= x(K+{1/2})S_z +{\bf K}\cdot {\bf S}$ at $x=\pm 1$ that was given by Happer et al$^{[1,2]}$ to interpret the curious degeneracies of the Zeeman effect for condensed vapor of $^{87}$Rb. The operators obey Yangian commutation relations. We show that the curious degeneracies seem to verify the Yangian algebraic structure for quantum tensor space and are consistent with the representation theory of $Y(sl(2))$.Comment: 8 pages, Latex fil

The Paratexts of Erotic Translation: Lady Chatterley’s Lover and Lolita in China

There is an increasing awareness that a translation product is composed of both the textual part and the promotional materials so that it is commercialised and socialised based on the market demand and the profile of the publisher. As a mediation between the readers and the translated text, the promotional materials, known as paratexts, can be very influential in familiarising consumers with the product, indicating the genre of the text and determining the target readership. While they play an essential role in managing how readers perceive the translation before they begin the book, they also reflect the publisher’s and the other producers’ voices in depicting the product based on its position in the social context as well as their assumptions about the preferences of the market. Thus, a study of translational paratexts allows us to observe the participation of different social agents and institutions in the process of production as well as their joint efforts to make the product more readily accepted by the target culture. In addition, the heterogeneous nature of paratexts generates additional reflections on research methodologies, such as the integration of the visual material analysis in the field of translation studies. In terms of research objects, Chinese translations of Lady Chatterley’s Lover and Lolita are selected as appropriate materials for case studies due to the fact that these two controversial works have received a great deal of attention from both the general public and the translation field in China since their publication. The long history of translation and retranslation of these two works makes them ideal for a diachronic study observing how the translation field and publishing industry have changed in the past several decades in China. At the same time, their controversial nature highlights the struggles and compromises of the publishers due to the socio-political context

Hydrodynamics investigation of in-vitro dissolution testing

Dissolution testing is routinely carried out in the pharmaceutical industry to determine dissolution rate of solid dosage forms. The United States Pharmacopoeia (USP) Dissolution Apparatus II is the device most commonly used for this purpose. Despite its widespread use, dissolution testing remains susceptible to significant error and test failures. Limited information is available on the hydrodynamics of this apparatus, although hydrodynamic effects can play a major role on test performance. Laser-Doppler Velocimetry (LDV) and Computational Fluid Dynamics (CFD) were used here to experimentally map and computationally predict the velocity distribution inside a standard USP Apparatus II under the typical operating conditions mandated by the dissolution test procedure. The flow in the apparatus is strongly dominated by the tangential component of the velocity, but a low recirculation zone exists in the lower part of the hemispherical vessel bottom where the tablet dissolution process takes place. The velocities in this region change significantly over short distances along the vessel bottom, implying that small variations in the location of the tablet on the vessel bottom caused by the randomness of the tablet descent through the liquid result in significantly different velocities and velocity gradients near the tablet. CFD was also used to study the hydrodynamics when the impeller was placed at four different locations, all within the limits specified by USP. Small changes in impeller location, especially off-center, produced extensive changes in the velocity profiles and shear rates. The blend time to homogenize the liquid content was also obtained for a number of operating conditions using different experimental methods, a CFD-based computational approach, and a semi-theoretical model. Excellent agreement between data and predictions was obtained. The CFD results show that blend time is inversely proportional to the agitation speed, and that blend time is some two orders of magnitude smaller than the time typically required for appreciable tablet dissolution during the typical dissolution test, implying that the contents of this device can be considered to be well mixed during the typical test. Finally, dissolution tests with prednisone and salicylic acid tablets were conducted, in which the tablets were placed at different locations in the dissolution vessel in order to study the effect of local hydrodynamics on dissolution. The results show that tablet location has a major effect, and that statistically significant differences exist in the dissolution profiles between centrally located tablets and tablets positioned off-center, at it is often the case during testing. The dissolution process was modeled using an approach based on the use of experimentally determined mass transfer coefficients, mass transfer coefficient equations, CFD-predicted velocity profiles, and mass balances. The results can satisfactorily predict the data. The hydrodynamics of dissolution testing depends strongly on small differences in equipment configurations and operating conditions, which can have a profound effect on the flow field and shear rate experienced by the oral dosage form being tested, and hence the solid-liquid mass transfer and dissolution rate

Compression for quantum population coding

We study the compression of n quantum systems, each prepared in the same state belonging to a given parametric family of quantum states. For a family of states with f independent parameters, we devise an asymptotically faithful protocol that requires a hybrid memory of size (f/2)log(n), including both quantum and classical bits. Our construction uses a quantum version of local asymptotic normality and, as an intermediate step, solves the problem of compressing displaced thermal states of n identically prepared modes. In both cases, we show that (f/2)log(n) is the minimum amount of memory needed to achieve asymptotic faithfulness. In addition, we analyze how much of the memory needs to be quantum. We find that the ratio between quantum and classical bits can be made arbitrarily small, but cannot reach zero: unless all the quantum states in the family commute, no protocol using only classical bits can be faithful, even if it uses an arbitrarily large number of classical bits.Comment: 14 Pages, 4 Figures + Appendi