Scalable Method for Eliminating Residual ZZZZ Interaction between Superconducting Qubits

Unwanted $ZZ$ interaction is a quantum-mechanical crosstalk phenomenon which correlates qubit dynamics and is ubiquitous in superconducting qubit systems. It adversely affects the quality of quantum operations and can be detrimental in scalable quantum information processing. Here we propose and experimentally demonstrate a practically extensible approach for complete cancellation of residual $ZZ$ interaction between fixed-frequency transmon qubits, which are known for long coherence and simple control. We apply to the intermediate coupler that connects the qubits a weak microwave drive at a properly chosen frequency in order to noninvasively induce an ac Stark shift for $ZZ$ cancellation. We verify the cancellation performance by measuring vanishing two-qubit entangling phases and $ZZ$ correlations. In addition, we implement a randomized benchmarking experiment to extract the idling gate fidelity which shows good agreement with the coherence limit, demonstrating the effectiveness of $ZZ$ cancellation. Our method allows independent addressability of each qubit-qubit connection, and is applicable to both nontunable and tunable couplers, promising better compatibility with future large-scale quantum processors.Comment: Main text: 6 pages, 4 figures; Supplement: 7 pages, 6 figure

Optical Properties Of A Novel Parabolic Quantum Well Structure In Ingan/Gan Light Emitters

We theoretically investigate the optical properties of conventional, normal (type A) parabolic and novel (type B) parabolic InGaN quantum well (QW) for blue light emitters. Two specially designed active layer structures by parabolic-shaped QW are proposed, and the optical characteristics of these two parabolic QW structures are calculated and compared to those of conventional QW structures. The electron-hole wavefunction overlap (Γe-hh) of type-B parabolic QWs is 2.8 times (69.6%) that in the conventional QW (24.8%), and the spontaneous emission rate is ninefold that of conventional QWs. The transparency carrier density of type-B parabolic QWs is much smaller than type-A parabolic or conventional QW. These results can be attributed to a higher indium index in the center of the type-B parabolic QWs, and that leads to better confinement of carriers wavefunctions

Improving FMCW GPR Precision through the CZT Algorithm for Pavement Thickness Measurements

Ground Penetrating Radar (GPR) application in road surface detection has been greatly developed in the past few decades, which enables rapid and economical estimation of pavement thickness and other physical properties in non-destructive testing (NDT) and non-contact testing (NCT). In recent years, with the rapid development of microwave and millimeter-wave solid-state devices and digital signal processors, the cost of Frequency-Modulated Continuous-Wave (FMCW) radar has dropped significantly, with smaller size and lighter weight. Thereafter, FMCW GPR is considered to be applied during pavement inspection. To improve the precision of FMCW GPR for NDT and NCT of pavement thickness, a Chirp Z-transform (CZT) algorithm is introduced to FMCW GPR and investigated in this paper. A FMCW + CZT GPR at 2.5 GHz with a bandwidth of 1 GHz was built, and laboratory and field experiments were carried out. The experimental results demonstrate that the FMCW + CZT GPR radar can obtain the sample thickness with low error and recognize subtle thickness variations. This method realizes the high precision thickness measurement of shallow asphalt pavement by FMCW radar with a narrow bandwidth pulse signal and would provide a promising low-cost measurement solution for GPR

Effects of Fermented Navel Orange Pulp on Growth Performance, Carcass Characteristics, Meat Quality, Meat Nutritional Value, and Serum Biochemical Indicators of Finishing Tibetan Pigs

In order to cope with the limited supply of feed for global animal production, there is a pressing need to explore alternative feed resources. Orange pulp, a by-product of agriculture and industry, has shown potential to positively or neutrally impact pig productive performance when included in their diet. However, there is a lack of research on the effects of fermented navel orange pulp (FNOP) on pig growth and productive performance. This study aimed to investigate the effects of FNOP as a dry matter substitute on pig’s growth performance, carcass characteristics, meat quality, meat nutritional value, and serum biochemical indicators. The experiment involved 128 finishing Tibetan pigs, divided into four feed treatment groups, with varying levels (0%, 5%, 10% and 15%) of FNOP replacing dry matter in the basal diet. The results indicate that substituting 5% to 15% FNOP had no adverse effects on pig growth performance. However, at a 15% substitution rate, there was a decrease in serum growth hormone and IGF-1 levels, along with an increase in the feed-to-gain ratio. A 10% FNOP replacement notably increased the loin-eye muscle area of pigs. Additionally, 5% and 10% FNOP substitutions reduced the drip loss of pork. The study also found that substituting 5% to 15% FNOP increased unsaturated fatty acids and umami nucleotide contents in pork and raised serum total protein and uric acid (nucleotide-metabolism-related product) levels. These findings suggest that moderate FNOP substitution might improve meat quality, nutritional value, and maintain growth and productive performance in Tibetan pigs by improving protein synthesis and nucleotide metabolism, while also reducing feed costs. The optimal substitution ratio identified was 10%

MGST1 May Regulate the Ferroptosis of the Annulus Fibrosus of Intervertebral Disc: Bioinformatic Integrated Analysis and Validation

Background: The objective of this research was to identify differentially expressed genes (DEGs) related to ferroptosis in the annulus fibrosus (AF) during intervertebral disc degeneration (IDD). Methods: We analyzed gene data from degenerated and normal AF obtained from the GSE70362 and GSE147383 datasets. An analysis to determine the functional significance of the DEGs was conducted, followed by the creation of a network illustrating the interactions between proteins. We further analyzed the immune infiltration of the DEGs and determined the hub DEGs using LASSO regression analysis. Finally, we identified the hub ferroptosis-related DEGs (FRDEGs) and verified their expression levels using Real-time quantitative polymerase chain reaction (RT-qPCR), Western blot, Immunohistochemical Staining (IHC), and Immunofluorescence (IF). Results: By analyzing the GSE70362 and GSE147383 datasets, we identified 118 DEGs. In degenerative AF groups, we observed a significant increase in immune infiltration of resting memory CD4+ T cells. LASSO regression analysis revealed 9 hub DEGs. The construction of a Receiver Operating Characteristic (ROC) curve yielded an Area Under the Curve (AUC) value of 0.762. Furthermore, we found that MGST1 is a hub gene related to ferroptosis. Our examination of immune infiltration indicated that MGST1 primarily influences macrophage M0 in different immune cell expression groups. Finally, our observations revealed a marked upregulation of MGST1 expression in the degenerated annulus fibrosus tissue. Conclusion: Our findings indicate an upsurge in MGST1 levels within degenerative AF, potentially playing a crucial role in the exacerbation of IDD. These findings provide a foundation for further exploration of the pathological mechanisms underlying IDD and offer potential drug targets for intervention

Dislocation Reduction and Stress Relaxation of GaN and InGaN Multiple Quantum Wells with Improved Performance via Serpentine Channel Patterned Mask.

The existence of high threading dislocation density (TDD) in GaN-based epilayers is a long unsolved problem, which hinders further applications of defect-sensitive GaN-based devices. Multiple-modulation of epitaxial lateral overgrowth (ELOG) is used to achieve high-quality GaN template on a novel serpentine channel patterned sapphire substrate (SCPSS). The dislocation blocking brought by the serpentine channel patterned mask, coupled with repeated dislocation bending, can reduce the dislocation density to a yet-to-be-optimized level of ∼2 × 10(5) to 2 × 10(6) cm(-2). About 80% area utilization rate of GaN with low TDD and stress relaxation is obtained. The periodical variations of dislocation density, optical properties and residual stress in GaN-based epilayers on SCPSS are analyzed. The quantum efficiency of InGaN/GaN multiple quantum wells (MQWs) on it can be increased by 52% compared with the conventional sapphire substrate. The reduced nonradiative recombination centers, the enhanced carrier localization, and the suppressed quantum confined Stark effect, are the main determinants of improved luminous performance in MQWs on SCPSS. This developed ELOG on serpentine shaped mask needs no interruption and regrowth, which can be a promising candidate for the heteroepitaxy of semipolar/nonpolar GaN and GaAs with high quality

Experimental Realization of Two Qutrits Gate with Tunable Coupling in Superconducting Circuits

Gate-based quantum computation has been extensively investigated using quantum circuits based on qubits. In many cases, such qubits are actually made out of multilevel systems but with only two states being used for computational purpose. While such a strategy has the advantage of being in line with the common binary logic, it in some sense wastes the ready-for-use resources in the large Hilbert space of these intrinsic multi-dimensional systems. Quantum computation beyond qubits (e.g., using qutrits or qudits) has thus been discussed and argued to be more efficient than its qubit counterpart in certain scenarios. However, one of the essential elements for qutrit-based quantum computation, two-qutrit quantum gate, remains a major challenge. In this work, we propose and demonstrate a highly efficient and scalable two-qutrit quantum gate in superconducting quantum circuits. Using a tunable coupler to control the cross-Kerr coupling between two qutrits, our scheme realizes a two-qutrit conditional phase gate with fidelity 89.3% by combining simple pulses applied to the coupler with single-qutrit operations. We further use such a two-qutrit gate to prepare an EPR state of two qutrits with a fidelity of 95.5%. Our scheme takes advantage of a tunable qutrit-qutrit coupling with a large on/off ratio. It therefore offers both high efficiency and low cross talk between qutrits, thus being friendly for scaling up. Our work constitutes an important step towards scalable qutrit-based quantum computation.Comment: 12 pages, 8 figure