We report on an experimental simulation of the spin-1 Heisenberg model with composite bosons in a one-dimensional chain based on the two-component Bose-Hubbard model. Exploiting our site- and spin-resolved quantum gas microscope, we observed faster superexchange dynamics of the spin-1 system compared to its spin-1/2 counterpart, which is attributed to the enhancement effect of multi-bosons. We further probed the nonequilibrium spin dynamics driven by the superexchange and single-ion anisotropy terms, unveiling the linear expansion of the spin-spin correlations, which is limited by the Lieb-Robinson bound.
View Article and Find Full Text PDFUltracold atoms in optical lattices form a competitive candidate for quantum computation owing to the excellent coherence properties, the highly parallel operations over spins, and the ultralow entropy achieved in qubit arrays. For this, a massive number of parallel entangled atom pairs have been realized in superlattices. However, the more formidable challenge is to scale up and detect multipartite entanglement, the basic resource for quantum computation, due to the lack of manipulations over local atomic spins in retroreflected bichromatic superlattices.
View Article and Find Full Text PDFGauge theory and thermalization are both topics of essential importance for modern quantum science and technology. The recently realized atomic quantum simulator for lattice gauge theories provides a unique opportunity for studying thermalization in gauge theory, in which theoretical studies have shown that quantum thermalization can signal the quantum phase transition. Nevertheless, the experimental study remains a challenge to accurately determine the critical point and controllably explore the thermalization dynamics due to the lack of techniques for locally manipulating and detecting matter and gauge fields.
View Article and Find Full Text PDFOptical lattices for coherently manipulating ultracold atoms demand high-power, low-noise, narrow-line-width, and continuous-wave lasers. Here, we report the implementation of a 30 W 532 nm low-noise laser by second harmonic generation from a 1064 nm fiber laser, which is capable to generate optical lattices for a quantum gas microscope of Rb87 atoms. The overall conversion efficiency is 59% at an input power of 51 W with a lithium triborate crystal coupled to a ring cavity.
View Article and Find Full Text PDFWe present a compact and gain-enhanced microwave helical antenna for manipulating ultracold Rb atoms coherently. By replacing the reflecting plate with an enhancing cup, the voltage standing wave ratio is reduced by 0.5 in the frequency range of 6.
View Article and Find Full Text PDFLow-noise, high-power 532-nm lasers are of great interest in many scientific research studies, such as gravitational wave detection and ultracold atom experiments. In particular, in the experiments of quantum gas microscopy, a large power of laser is necessary during the imaging process, while low noise is important for preventing the atoms from being heated up. In this work, we report on the generation of such a 532-nm continuous-wave laser by coherently combining two laser beams produced by single-pass second-harmonic generation.
View Article and Find Full Text PDFObjective: The present study investigated the predictive value of each perfusion parameter of the Alberta Stroke Program Early Computed Tomography Score (ASPECTS) in CT perfusion (CTP) imaging for the prognosis of endovascular treatment at the time of admission in patients with acute ischemic stroke in the anterior circulation.
Patients And Methods: The imaging data of 62 patients with acute ischemic stroke in the anterior circulation with an onset time of 6 h or less were retrospectively analyzed. All patients underwent the one-stop whole-brain dynamic volume four-dimensional (4D) CT angiography (CTA)-CTP and cranial magnetic resonance imaging (MRI) within seven days after treatment.
Optical superlattice has a wide range of applications in the study of ultracold atom physics. Especially, it can be used to trap and manipulate thousands of atom pairs in parallel which constitutes a promising system for quantum simulation and quantum computation. In the present work, we report on a high-power optical superlattice formed by a 532-nm and 1064-nm dual-wavelength interferometer with a short lattice spacing of 630 nm.
View Article and Find Full Text PDFCurrent sources with extremely low noise are significant for many branches of scientific research, such as experiments of ultra-cold atoms, superconducting quantum computing, and precision measurements. Here we construct and characterize an analog-controlled bipolar current source with high bandwidth and ultra-low noise. A precise and stable resistor is connected in series with the output for current sensing.
View Article and Find Full Text PDFA novel conjugated microporous polymer based on perylene tetraanhydride bisimide (DPA) has been synthesized through Sonogashira-Hagihara cross-coupling polymerization of tetrabromo-substituted perylene tetraanhydride bisimide derivative (DPBrABr) with 1,4-diethynylbenzene, whose Brunauer-Emmett-Teller (BET) specific surface area is about 378 m g. The fluorescence quenching behaviors of the DPA were investigated. It is found that the DPA shows high sensitivity and selectivity to tracing o-nitrophenol (o-NP) in THF with Ks constant of 2.
View Article and Find Full Text PDFThe aim of this study was to determine the clinical significance of the results of screening of newborn hearing and the incidence of deafness-susceptibility genes. One thousand newborn babies in the Handan Center Hospital (Handan, China) underwent screening of hearing and deafness-susceptibility genes. The first screening test was carried out using otoacoustic emissions (OAEs).
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