We study the resonant optical transitions of a single nitrogen-vacancy (NV) center that is coherently dressed by a strong mechanical drive. Using a gigahertz-frequency diamond mechanical resonator that is strain coupled to a NV center's orbital states, we demonstrate coherent Raman sidebands out to the ninth order and orbital-phonon interactions that mix the two excited-state orbital branches. These interactions are spectroscopically revealed through a multiphonon Rabi splitting of the orbital branches which scales as a function of resonator driving amplitude and is successfully reproduced in a quantum model. Finally, we discuss the application of mechanical driving to engineering NV-center orbital states.

Diamond-based microelectromechanical systems (MEMS) enable direct coupling between the quantum states of nitrogen-vacancy (NV) centers and the phonon modes of a mechanical resonator. One example, diamond high-overtone bulk acoustic resonators (HBARs), feature an integrated piezoelectric transducer and support high-quality factor resonance modes into the GHz frequency range. The acoustic modes allow mechanical manipulation of deeply embedded NV centers with long spin and orbital coherence times. Unfortunately, the spin-phonon coupling rate is limited by the large resonator size, > 100 µm, and thus strongly-coupled NV electron-phonon interactions remain out of reach in current diamond BAR devices. Here, we report the design and fabrication of a semi-confocal HBAR (SCHBAR) device on diamond (silicon carbide) with 1 arXiv:1906.06309v1 [cond-mat.mes-hall] 14 Jun 2019 f · Q > 10 12 (> 10 13 ). The semi-confocal geometry confines the phonon mode laterally below 10 µm. This drastic reduction in modal volume enhances defect center electronphonon coupling. For the native NV centers inside the diamond device, we demonstrate mechanically driven spin transitions and show a high strain-driving efficiency with a Rabi frequency of (2π)2.19(14) MHz/V p , which is comparable to a typical microwave antenna at the same microwave power.Defect-based qubits are attractive platforms for solid state quantum technologies. 1 The leading examples are the nitrogen-vacancy (NV) 2 center and the silicon-vacancy (SiV) 3 center in diamond, and the divacancy center 4 and the silicon vacancy center (V Si ) 5 in silicon carbide (SiC). Hybrid quantum systems based on these defect qubits are particularly interesting because they interface the qubit spin to photons or phonons and thus potentially enable the transport of quantum information. For sensing applications, they offer unconventional modalities of quantum control which is a resource for extending the coherence time and thus sensitivity. Coupling spins to mechanical motion could also enable new quantum-enhanced sensors of motion, such as inertial sensing. 6,7 Although solid state spin-photon entanglement has been demonstrated in recent years 8 and has been used to build quantum networks, 9 defect-based spin-mechanical systems have yet to operate at the single phonon quantum level because they are limited by weak electronphonon coupling, g, in existing devices. Considering g ∝ 1/V , where V is the modal volume, one approach to strengthening the coupling is to engineer small mode volume mechanical resonators with high quality factors. Ultimately, defect-based spin-mechanical systems may enable new sensing applications and control of phonon states at the quantum level. 10Defect-based spin-mechanical systems can be classified into two categories: 1) micro-beam resonator systems 11-13 and 2) micro-electromechanical systems (MEMS) 14-17 with integrated thin-film piezoelectric transducers. While the first category minimizes the resonator fabrication to a single material, i.e., diamond, SiC, etc., high...

This study examined the prognostic value of the baseline red blood cell distribution width (RDW) in diffuse large B cell lymphoma (DLBCL) patients. The associations between RDW and clinical characteristics were assessed in 161 DLBCL patients from 2005 to 2016. The log-rank test, univariate analysis, and Cox regression analysis were used to evaluate the relationship between RDW and survival. A RDW of 14.1% was considered to be the optimal cut-off value for predicting prognosis. A high RDW was associated with more frequent B symptoms (P=0.001), a higher International Prognostic Index score (P=0.032), more extranodal sites of disease (P=0.035), and significantly lower Eastern Cooperative Oncology Group performance status (P=0.031). The log-rank test demonstrated that patients with a high RDW had a shorter overall survival (OS) (2-year OS rate, 53.6% vs. 83.6%, P<0.001) and progression-free survival (PFS) (2-year PFS rate, 44.7% vs. 81.8%, P<0.001). The multivariate analysis demonstrated that RDW ≥14.1% was an independent predictor of OS (odds ratio [OR] = 0.345, P<0.001) and PFS (OR = 0.393, P=0.001). We demonstrated that a high RDW predicted an unfavorable prognosis in patients with DLBCL.

A flexible UV photodetector (PD) has been fabricated based on the amorphous InGaZnO film. It shows good photoresponse characteristics before and after bending, and fast response speed compared with the most reported flexible UV PDs.

BackgroundAn early and accurate evaluation of the risk of bronchopulmonary dysplasia (BPD) in premature infants is pivotal in implementing preventive strategies. The risk prediction models nowadays for BPD risk that included only clinical factors but without genetic factors are either too complex without practicability or provide poor-to-moderate discrimination. We aim to identify the role of genetic factors in BPD risk prediction early and accurately.MethodsExome sequencing was performed in a cohort of 245 premature infants (gestational age &lt;32 weeks), with 131 BPD infants and 114 infants without BPD as controls. A gene burden test was performed to find risk genes with loss-of-function mutations or missense mutations over-represented in BPD and severe BPD (sBPD) patients, with risk gene sets (RGS) defined as BPD–RGS and sBPD–RGS, respectively. We then developed two predictive models for the risk of BPD and sBPD by integrating patient clinical and genetic features. The performance of the models was evaluated using the area under the receiver operating characteristic curve (AUROC).ResultsThirty and 21 genes were included in BPD–RGS and sBPD–RGS, respectively. The predictive model for BPD, which combined the BPD–RGS and basic clinical risk factors, showed better discrimination than the model that was only based on basic clinical features (AUROC, 0.915 vs. AUROC, 0.814, P = 0.013, respectively) in the independent testing dataset. The same was observed in the predictive model for sBPD (AUROC, 0.907 vs. AUROC, 0.826; P = 0.016).ConclusionThis study suggests that genetic information contributes to susceptibility to BPD. The predictive model in this study, which combined BPD–RGS with basic clinical risk factors, can thus accurately stratify BPD risk in premature infants.