Florida State University

About: Florida State University is a education organization based out in Tallahassee, Florida, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 25117 authors who have published 65361 publications receiving 2527087 citations. The organization is also known as: FSU & Florida State.

Enhancing coherence in molecular spin qubits via atomic clock transitions

Abstract: Quantum computing is an emerging area within the information sciences revolving around the concept of quantum bits (qubits). A major obstacle is the extreme fragility of these qubits due to interactions with their environment that destroy their quantumness. This phenomenon, known as decoherence, is of fundamental interest. There are many competing candidates for qubits, including superconducting circuits, quantum optical cavities, ultracold atoms and spin qubits, and each has its strengths and weaknesses. When dealing with spin qubits, the strongest source of decoherence is the magnetic dipolar interaction. To minimize it, spins are typically diluted in a diamagnetic matrix. For example, this dilution can be taken to the extreme of a single phosphorus atom in silicon, whereas in molecular matrices a typical ratio is one magnetic molecule per 10,000 matrix molecules. However, there is a fundamental contradiction between reducing decoherence by dilution and allowing quantum operations via the interaction between spin qubits. To resolve this contradiction, the design and engineering of quantum hardware can benefit from a 'bottom-up' approach whereby the electronic structure of magnetic molecules is chemically tailored to give the desired physical behaviour. Here we present a way of enhancing coherence in solid-state molecular spin qubits without resorting to extreme dilution. It is based on the design of molecular structures with crystal field ground states possessing large tunnelling gaps that give rise to optimal operating points, or atomic clock transitions, at which the quantum spin dynamics become protected against dipolar decoherence. This approach is illustrated with a holmium molecular nanomagnet in which long coherence times (up to 8.4 microseconds at 5 kelvin) are obtained at unusually high concentrations. This finding opens new avenues for quantum computing based on molecular spin qubits.

Predicting Who Reoffends: The Neglected Role of Neighborhood Context in Recidivism Studies

Abstract: Prior studies of recidivism have focused almost exclusively on individual-level characteristics of offenders and their offenses to explore the correlates of reoffending. Notably absent from these studies are measures reflecting the neighborhood contexts in which individuals live. The current research addresses this shortcoming. Using data on a sample of ex-offenders in Multnomah County, Oregon (Portland and surrounding area) in conjunction with 2000 census data, we answer two questions. First, which individual-level factors influence rates of recidivism? Second, to what extent does neighborhood socioeconomic status account for variation in the reoffending behavior of ex-prisoners that is not explained by their individual-level characteristics? We find that those who return to disadvantaged neighborhoods recidivate at a greater rate while those who return to resource rich or affluent communities recidivate at a lesser rate, controlling for individual-level factors.

The 30–50 Day Mode at 850 mb During MONEX

Abstract: The analyzed wind field at 850 mb during the summer monsoon experiment (MONEX) is subjected to a time series analysis to confirm the existence of a peak in the time range of 30–50 days. Having established that, this study presents a mapping of the motion field for this time scale. In this short paper we illustrate the steady meridional propagation of a train of troughs and ridges that seem to form near the equator and dissipate near the Himalayas. The meridional scale of this mode is around 300 km, and its meridional speed of propagation is ∼0.75° latitude per day. The amplitude of the wind for this mode is around 3–6 m s−1. The salient contributions here are the mapping and the demonstration of a very regular behavior of this mode; its existence is here noted from a period well before the onset of monsoon, i.e., from early May to late July. Three major storms during MONEX were noted to form within the trough line of this system, and the period of major cessation of rains over the Indian subconti...

Mangroves, a major source of dissolved organic carbon to the oceans

Abstract: [1] Organic matter, which is dissolved in low concentrations in the vast waters of the oceans, contains a total amount of carbon similar to atmospheric carbon dioxide To understand global biogeochemical cycles, it is crucial to quantify the sources of marine dissolved organic carbon (DOC) We investigated the impact of mangroves, the dominant intertidal vegetation of the tropics, on marine DOC inventories Stable carbon isotopes and proton nuclear magnetic resonance spectroscopy showed that mangroves are the main source of terrigenous DOC in the open ocean off northern Brazil Sunlight efficiently destroyed aromatic molecules during transport offshore, removing about one third of mangrove-derived DOC The remainder was refractory and may thus be distributed over the oceans On a global scale, we estimate that mangroves account for >10% of the terrestrially derived, refractory DOC transported to the ocean, while they cover only <01% of the continents' surface

Evolution of land surface air temperature trend

Abstract: The global climate has been experiencing significant warming at an unprecedented pace in the past century(1,2). This warming is spatially and temporally non-uniform, and one needs to understand its evolution to better evaluate its potential societal and economic impact. Here, the evolution of global land surface air temperature trend in the past century is diagnosed using the spatial-temporally multidimensional ensemble empirical mode decomposition method(3). We find that the noticeable warming (>0.5 K) started sporadically over the global land and accelerated until around 1980. Both the warming rate and spatial structure have changed little since. The fastest warming in recent decades (>0.4 K per decade) occurred in northern mid-latitudes. From a zonal average perspective, noticeable warming (>0.2 K since 1900) first took place in the subtropical and subpolar regions of the Northern Hemisphere, followed by subtropical warming in the Southern Hemisphere. The two bands of warming in the Northern Hemisphere expanded from 1950 to 1985 and merged to cover the entire Northern Hemisphere.