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Operation speed and coherence time are two core measures for the viability of a qubit. Strong spin-orbit interaction (SOI) and relatively weak hyperfine interaction make holes in germanium (Ge) intriguing candidates for spin qubits with rapid, all-electrical coherent control. Here we report ultrafast single-spin manipulation in a hole-based double quantum dot in a germanium hut wire (GHW). Mediated by the strong SOI, a Rabi frequency exceeding 540 MHz is observed at a magnetic field of 100 mT, setting a record for ultrafast spin qubit control in semiconductor systems. We demonstrate that the strong SOI of heavy holes (HHs) in our GHW, characterized by a very short spin-orbit length of 1.5 nm, enables the rapid gate operations we accomplish. Our results demonstrate the potential of ultrafast coherent control of hole spin qubits to meet the requirement of DiVincenzo’s criteria for a scalable quantum information processor. Hole-spin qubits in germanium are promising candidates for rapid, all-electrical qubit control. Here the authors report Rabi oscillations with the record frequency of 540 MHz in a hole-based double quantum dot in a germanium hut wire, which is attributed to strong spin-orbit interaction of heavy holes.

Mechanical resonators are promising systems for storing and manipulating information. To transfer information between mechanical modes, either direct coupling or an interface between these modes is needed. In previous works, strong coupling between different modes in a single mechanical resonator and direct interaction between neighboring mechanical resonators have been demonstrated. However, coupling between distant mechanical resonators, which is a crucial request for long-distance classical and quantum information processing using mechanical devices, remains an experimental challenge. Here, we report the experimental observation of strong indirect coupling between separated mechanical resonators in a graphene-based electromechanical system. The coupling is mediated by a far-off-resonant phonon cavity through virtual excitations via a Raman-like process. By controlling the resonant frequency of the phonon cavity, the indirect coupling can be tuned in a wide range. Our results may lead to the development of gate-controlled all-mechanical devices and open up the possibility of long-distance quantum mechanical experiments. Non-neighbouring mechanical resonators can interact via indirect coupling. Here, the authors leverage a resonant phonon cavity in a graphene-based electromechanical system to demonstrate strong indirect coupling between separated mechanical resonators.

The germanium (Ge) hut wire system has strong spin-orbit coupling, a long coherence time due to a very large heavy-light hole splitting, and the advantage of site-controlled large-scale hut wire positioning. These properties make the Ge hut wire a promising candidate for the realization of strong coupling of spin to superconducting resonators and scalability for multiple qubit coupling. We have coupled a reflection line resonator to a hole double quantum dot (DQD) formed in Ge hut wire. The amplitude and phase responses of the microwave resonator revealed that the charge stability diagrams of the DQD are in good agreement with those obtained from transport measurements. The DQD interdot tunneling rate is shown to be tunable from 6.2 GHz to 8.5 GHz, which demonstrates the ability to adjust the frequency detuning between the qubit and the resonator. Furthermore, we achieved a hole-resonator coupling strength of up to 15 MHz, with a charge qubit decoherence rate of 0.28 GHz. Meanwhile the hole spin-resonator coupling rate was estimated to be 3 MHz. These results suggest that holes of a DQD in a Ge hut wire are dipole coupled to microwave photons, potentially enabling tunable hole spin-photon interactions in Ge with an inherent spin-orbit coupling.

Vibrational modes in mechanical resonators provide a promising candidate to interface and manipulate classical and quantum information. The observation of coherent dynamics between distant mechanical resonators can be a key step toward scalable phononbased applications. Here we report tunable coherent phonon dynamics with an architecture comprising three graphene mechanical resonators coupled in series, where all resonators can be manipulated by electrical signals on control gates. We demonstrate coherent Rabi oscillations between spatially separated resonators indirectly coupled via an intermediate resonator serving as a phonon cavity. The Rabi frequency fits well with the microwave burst power on the control gate. We also observe Ramsey interference, where the oscillation frequency corresponds to the indirect coupling strength between these resonators. Such coherent processes indicate that information encoded in vibrational modes can be transferred and stored between spatially separated resonators, which can open the venue of on-demand phonon-based information processing.

Background Intra-abdominal candidiasis (IAC) is the predominant type of invasive candidiasis with high mortality in surgical intensive care patients. The purpose of this study was to investigate the impact of appropriate source control and antifungal therapy on the outcomes of critically ill surgical patients with IAC. Methods This was a retrospective single-center cohort study. Adult surgical patients who were admitted to the intensive care unit and diagnosed with IAC from January 1, 2003, to December 31, 2016, were enrolled. The patients’ data including risk factors of IAC, infection-related information, antifungal treatment and 30-day outcomes were collected. The primary endpoint was 30-day mortality. A COX proportional hazards model was used to analyze the association between appropriate treatment and 30-day survival. Results A total of 82 patients were included in the analysis. Of these, 45 (54.9%) were complicated with septic shock at IAC diagnosis. Types of IAC included peritonitis (61.0%), intra-abdominal abscesses (23.2%) and biliary tract infections (15.9%). Of the included patients, 53 (64.6%) received appropriate source control and 44 (53.7%) appropriate antifungal therapy. Compared with patients with neither of these treatments, appropriate source control (HR 0.08, 95% CI 0.02–0.30; P  < 0.001), appropriate antifungal therapy (HR 0.14, 95% CI 0.04–0.55; P  = 0.005), and a combination of these treatments (HR 0.02, 95% CI 0.00–0.08; P  < 0.001) were associated with reduced risk of death within 30 days after IAC diagnosis. Conclusion For critically ill surgical patients with IAC, both appropriate source control and appropriate antifungal therapy were associated with reduced risk of 30-day mortality, and the protective effects of the two appropriate treatments were additive.

Universal multiple-qubit gates can be implemented by a set of universal single-qubit gates and any one kind of entangling two-qubit gate, such as a controlled-NOT gate. For semiconductor quantum dot qubits, two-qubit gate operations have so far only been demonstrated in individual electron spin-based quantum dot systems. Here we demonstrate the conditional rotation of two capacitively coupled charge qubits, each consisting of an electron confined in a GaAs/AlGaAs double quantum dot. Owing to the strong inter-qubit coupling strength, gate operations with a clock speed up to 6 GHz have been realized. A truth table measurement for controlled-NOT operation shows comparable fidelities to that of spin-based two-qubit gates, although phase coherence is not explicitly measured. Our results suggest that semiconductor charge qubits have a considerable potential for scalable quantum computing and may stimulate the use of long-range Coulomb interaction for coherent quantum control in other devices. Quantum-information processing requires gates that can operate on multiple qubits. Here, the authors demonstrate a controlled-NOT gate operation on two coupled charge qubits comprising electrons confined in semiconductor double quantum dots.

Achieving high-fidelity and robust qubit manipulations is a crucial requirement for realizing fault-tolerant quantum computation. Here, we demonstrate a single-hole spin qubit in a germanium quantum dot and characterize its control fidelity using gate set tomography. The maximum control fidelities reach 97.48%, 99.81%, 99.88% for the I , X /2 and Y /2 gate, respectively. These results reveal that off-resonance noise during consecutive I gates in gate set tomography sequences severely limits qubit performance. Therefore, we introduce geometric quantum computation to realize noise-resilient qubit manipulation. The geometric gate control fidelities remain above 99% across a wide range of Rabi frequencies. The maximum fidelity surpasses 99.9%. Furthermore, the fidelities of geometric X /2 and Y /2 ( I ) gates exceed 99% even when detuning the microwave frequency by  ± 2.5 MHz (± 1.2 MHz), highlighting the noise-resilient feature. These results demonstrate that geometric quantum computation is a potential method for achieving high-fidelity qubit manipulation reproducibly in semiconductor quantum computation. Geometric quantum gates—engineered evolution paths for qubit control—promise noise resilience but have shown limited fidelity in prior implementations in semiconductor quantum computation. Here the authors demonstrate high-fidelity single-qubit gates in a single-hole quantum dot in Ge, outperforming conventional dynamical gates.

Colon cancer stem cells (CSCs) have been shown to be responsible for the recurrence and metastasis of colorectal cancer (CRC). As a crucial microenvironmental factor, extracellular matrix (ECM) stiffness is known to affect the stemness of CSCs. Recently, fibrin deposition in the stroma of CRC was demonstrated to be responsible for tumor development. In this study, we used salmon fibrin gel to provide a 3D ECM for colon cancer cells and investigated its effects on cell growth as well as the underlying mechanisms. Compared with stiff 420 Pascal (Pa) and 1 050 Pa gels, 90 Pa soft fibrin gel was most efficient at isolating and enriching tumor colonies. The size and number of colony formation negatively correlated with gel stiffness. Specifically, these tumor colonies exhibited efficient tumorigenicity, upregulated stem cell markers, and had anti-chemotherapeutic properties and were thus named tumor-repopulating cells (TRCs). More importantly, the self-renewal molecule Nanog was sharply induced in 3D-cultured colon TRCs; further, Nanog siRNA significantly inhibited colony formation, suggesting the indispensable role of Nanog in TRC growth. A subsequent mechanistic study illustrated that Nanog expression could be modulated through fibrin gel stiffness-induced DAB2IP/PI3K/FOXA1 signaling in colon TRCs.

Although recent research progress on the abundant C-to-U RNA editing events in plant chloroplasts and mitochondria has uncovered many recognition factors and their molecular mechanisms, the intrinsic regulation of RNA editing within plants remains largely unknown. This study aimed to establish a regulatory relationship in Arabidopsis between the plant hormone auxin and chloroplast RNA editing. We first analyzed auxin response elements (AuxREs) present within promoters of chloroplast editing factors reported to date. We found that each has more than one AuxRE, suggesting a potential regulatory role of auxin in their expression. Further investigation unveiled that the depletion of auxin synthesis gene YUC2 reduces the expression of several editing factors. However, in yuc2 mutants, only the expression of CRR4, DYW1, ISE2, and ECD1 editing factors and the editing efficiency of their corresponding editing sites, ndhD-2 and rps14-149, were simultaneously suppressed. In addition, exogenous IAA and the overexpression of YUC2 enhanced the expression of these editing factors and the editing efficiency at the ndhD-2 and rps14-149 sites. These results suggested a direct effect of auxin upon the editing of the ndhD-2 and rps14-149 sites through the modulation of the expression of the editing factors. We further demonstrated that ARF1, a downstream transcription factor in the auxin-signaling pathway, could directly bind to and inactivate the promoters of CRR4, DYW1, and ISE2 in a dual-luciferase reporter system, thereby inhibiting their expression. Moreover, the overexpression of ARF1 in Arabidopsis significantly reduced the expression of the three editing factors and the editing efficiency at the ndhD-2 and rps14-149 sites. These data suggest that YUC2-mediated auxin biosynthesis governs the RNA-editing process through the ARF1-dependent signal transduction pathway.

Standard semiconductor fabrication techniques are used to fabricate a quantum dot (QD) made of WS 2 , where Coulomb oscillations were found. The full-width-at-half-maximum of the Coulomb peaks increases linearly with temperature while the height of the peaks remains almost independent of temperature, which is consistent with standard semiconductor QD theory. Unlike graphene etched QDs, where Coulomb peaks belonging to the same QD can have different temperature dependences, these results indicate the absence of the disordered confining potential. This difference in the potential-forming mechanism between graphene etched QDs and WS 2 QDs may be the reason for the larger potential fluctuation found in graphene QDs.