ABSTRACT
Color centers with long-lived spins are established platforms for quantum sensing and quantum information applications. Color centers exist in different charge states, each of them with distinct optical and spin properties. Application to quantum technology requires the capability to access and stabilize charge states for each specific task. Here, we investigate charge state manipulation of individual silicon vacancies in silicon carbide, a system which has recently shown a unique combination of long spin coherence time and ultrastable spin-selective optical transitions. In particular, we demonstrate charge state switching through the bias applied to the color center in an integrated silicon carbide optoelectronic device. We show that the electronic environment defined by the doping profile and the distribution of other defects in the device plays a key role for charge state control. Our experimental results and numerical modeling evidence that control of these complex interactions can, under certain conditions, enhance the photon emission rate. These findings open the way for deterministic control over the charge state of spin-active color centers for quantum technology and provide novel techniques for monitoring doping profiles and voltage sensing in microscopic devices.
ABSTRACT
Spins in solids are cornerstone elements of quantum spintronics. Leading contenders such as defects in diamond or individual phosphorus dopants in silicon have shown spectacular progress, but either lack established nanotechnology or an efficient spin/photon interface. Silicon carbide (SiC) combines the strength of both systems: it has a large bandgap with deep defects and benefits from mature fabrication techniques. Here, we report the characterization of photoluminescence and optical spin polarization from single silicon vacancies in SiC, and demonstrate that single spins can be addressed at room temperature. We show coherent control of a single defect spin and find long spin coherence times under ambient conditions. Our study provides evidence that SiC is a promising system for atomic-scale spintronics and quantum technology.
ABSTRACT
BACKGROUND: Clinical antipsychotic trials of intervention effectiveness showed that atypical antipsychotics (AAPs) were associated with significant weight gain and glucose intolerance. A few trials have shown topiramate to reduce weight gain in patients receiving AAPs, although this benefit has not been present in all trials. OBJECTIVE: This study aimed to determine topiramate therapy's impact on weight gain in patients receiving AAPs. DATA SOURCE: A systematic literature search of MEDLINE (1948 to July 8, 2011) and Cochrane CENTRAL (4th Quarter 2011) was conducted. STUDY SELECTION: Eight trials (n = 336 participants) met our inclusion criteria: randomized controlled trial, evaluated topiramate in patients taking AAPs, and reported weight change during the treatment course. DATA EXTRACTION: Two investigators (S.M. and C.I.C.) used a standardized data abstraction tool to independently collect data, with disagreement resolved through discussion. The difference between the mean weight in the topiramate and control groups was calculated as the weighted mean difference with accompanying 95% confidence interval. A random effect model was used for all analyses. DATA SYNTHESIS: Upon meta-analysis, we found that patients receiving topiramate lost weight or had attenuated weight gain compared to control patients (weighted mean difference, -2.83 kg; 95% confidence interval, -4.62 to -1.03). CONCLUSIONS: Our meta-analysis shows that using topiramate can prevent or reduce weight gain associated with AAPs.
