Quantum simulation of the quantum Rabi model in a trapped ion

The quantum Rabi model, involving a two-level system and a bosonic field mode, is arguably the simplest and most fundamental model describing quantum light-matter interactions. Historically, due to the restricted parameter regimes of natural light-matter processes, the richness of this model has been elusive in the lab. Here, we experimentally realize a quantum simulation of the quantum Rabi model in a single trapped ion, where the coupling strength between the simulated light mode and atom can be tuned at will. The versatility of the demonstrated quantum simulator enables us to experimentally explore the quantum Rabi model in detail, including a wide range of otherwise unaccessible phenomena, as those happening in the ultrastrong and deep strong coupling regimes. In this sense, we are able to adiabatically generate the ground state of the quantum Rabi model in the deep strong coupling regime, where we are able to detect the nontrivial entanglement between the bosonic field mode and the two-level system. Moreover, we observe the breakdown of the rotating-wave approximation when the coupling strength is increased, and the generation of phonon wave packets that bounce back and forth when the coupling reaches the deep strong coupling regime. Finally, we also measure the energy spectrum of the quantum Rabi model in the ultrastrong coupling regime.Comment: 8 pages, 4 figure

Honeybees are far too insufficient to supply optimum pollination services in agricultural systems worldwide

Evidence of a decline in wild pollinators is increasing across global and local habitats. However, with regional variation, the number of managed pollinators has increased globally. Whether these managed pollinators can sufficiently meet the agricultural pollination demand given wild pollinator declines remains unclear. Data on 49 honeybee-pollinated crops cultivated worldwide and stocked honeybee colonies were analysed to assess the pollination demand and pollination service capacity between 1989 and 2019. We found a rapidly increasing demand for honeybee pollination but a decreasing pollination service capacity of honeybee colonies. Globally, the demand for honeybee pollination rose approximately 2.3 times higher than the stocked number of honeybee colonies in 2019, growing 1.78% annually, almost 2 times faster than honeybee colonies (0.95%). On average, the pollination service capacity, growth rates of demands for honeybee colony stocks and honeybee pollination, and diversity of honeybee-pollinated crops varied regionally. Nevertheless, fluctuation of the honeybee-pollination demand increased with increased fluctuation of crop diversification. Oil crops accounted for over 70% of the world's honeybee-pollination demand in 2019, with soybean and rapeseed accounting for 39% and 16%, respectively. This was the case in less diversified countries, where a few crops dominated the demand for honeybee pollination, including American countries such as Argentina, Brazil, and the USA, compared to more diversified countries such as China, India, and Japan in Asia. Our study shows that managed pollinators are far too insufficient to adequately supply the agricultural pollination demand worldwide. This emphasises the importance of ongoing calls for protecting pollinators and the integrated management of honeybees and wild pollinator assemblages for a sustainable food-secure future world.Fil: Mashilingi, Shibonage K.. Chinese Academy of Sciences; República de ChinaFil: Zhang, Hong. Chinese Academy of Sciences; República de ChinaFil: Garibaldi, Lucas Alejandro. Universidad Nacional de Río Negro. Sede Andina. Instituto de Investigaciones en Recursos Naturales, Agroecología y Desarrollo Rural; ArgentinaFil: An, Jiandong. Chinese Academy of Sciences; República de Chin

Gold nanoparticles meet medical radionuclides

Thanks to their unique optical and physicochemical properties, gold nanoparticles have gained increased interest as radiosensitizing, photothermal therapy and optical imaging agents to enhance the effectiveness of cancer detection and therapy. Furthermore, their ability to carry multiple medically relevant radionuclides broadens their use to nuclear medicine SPECT and PET imaging as well as targeted radionuclide therapy. In this review, we discuss the radiolabeling process of gold nanoparticles and their use in (multimodal) nuclear medicine imaging to better understand their specific distribution, uptake and retention in different in vivo cancer models. In addition, radiolabeled gold nanoparticles enable image-guided therapy is reviewed aswell as the enhancement of targeted radionuclide therapy and nanobrachytherapy through an increased dose deposition and radiosensitization, as demonstrated by multiple Monte Carlo studies and experimental in vitro and in vivo studies. (C) 2021 The Authors. Published by Elsevier Inc

High-rate, high-fidelity entanglement of qubits across an elementary quantum network

We demonstrate remote entanglement of trapped-ion qubits via a quantum-optical fiber link with fidelity and rate approaching those of local operations. Two ${}^{88}$Sr${}^{+}$ qubits are entangled via the polarization degree of freedom of two photons which are coupled by high-numerical-aperture lenses into single-mode optical fibers and interfere on a beamsplitter. A novel geometry allows high-efficiency photon collection while maintaining unit fidelity for ion-photon entanglement. We generate remote Bell pairs with fidelity $F=0.940(5)$ at an average rate $182\,\mathrm{s}^{-1}$ (success probability $2.18\times10^{-4}$).Comment: v2 updated to include responses to reviewers, as published in PR

Influence of Tropical Climate Conditions on the Quality of Antihypertensive Drugs from Rwandan Pharmacies

The objective of this study was to assess the quality of antihypertensive drugs and to investigate the influence of tropical storage conditions. Drug content and in vitro dissolution tests were performed on 10 test formulations (from Rwanda) and 6 reference formulations (from Belgium or France) after purchase and after 6-month storage under long-term (25 +/- 2 degrees C and 60 +/- 5% relative humidity [RH]) and accelerated (40 +/- 2 degrees C and 75 +/- 5% RH) testing conditions. Twenty percent of test formulations were of substandard content at the time of purchase. After 6 months at accelerated testing conditions, 7 of 10 test formulations were substandard in content and 8 were substandard for the combined criteria of drug content and dissolution, whereas no reference drug became substandard. This study shows that, apart from some drugs being already substandard from purchase, accelerated testing conditions (simulating tropical climate) have deleterious effects on the majority of antihypertensive drug formulations found in the Rwandan market

Optimising bioreactor processes with in-situ product removal using mathematical programming: A case study for propionate production

Designing and operating bioreactors with in-situ product removal (ISPR) can be challenging, particularly in discontinuous systems, where the ISPR and substrate feeding need to be effectively scheduled. Mathematical models can help assess different scheduling regimes in the fermentation medium and provide a means to optimise the process. Focusing on a propionate production case study, a model of a co-culture batch fermentation with electrodialysis (the ISPR system), was developed. Using this model, the product yield and/or the productivity were maximised by 1) single objective optimisation maximising the product yield (0.49 gpropionate /gglucose) or productivity (0.75 gpropionate/L/h), 2) multi objective optimisation to pursue trade-off solutions between the yield and productivity and 3) a stochastic optimisation maximising the productivity robustly (0.64 gpropionate/L/h) to account for uncertainties associated to the model parameters. With this contribution it is demonstrated that, through mathematical models, ISPR can be implemented and adapted to the user's objectivesThis work was supported by project ALQUIMIA (PID2019-110993RJ-I00) funded by the Agencia Estatal de Investigación Alquimia: Proyecto de I- d-i Programa Retos de la sociedad modalidad Jovenes investigadores convocatoria. A. Regueira would like to acknowledge the support of the Xunta de Galicia through a postdoctoral fellowship (ED481B-2021-012)S