Variational Quantum Algorithms (VQAs) have emerged as a powerful class of algorithms that is highly suitable for noisy quantum devices. Therefore, investigating their design has become key in quantum computing research. Previous works have shown that choosing an effective parameterized quantum circuit (PQC) or ansatz for a VQA is crucial to its overall performance, especially on near-term devices. In this paper, we utilize pulse-level access to quantum machines, our understanding of their twoqubit interactions, and, more importantly, our knowledge of VQAs, to customize the design of two-qubit entanglers. Our analysis shows that utilizing customized pulse gates for ansatze reduces state preparation times by more than half, maintains expressibility relative to standard ansatze, and produces PQCs that are more trainable through local cost function analysis. Our algorithm performance results show that in three cases, our PQC configuration outperforms the base implementation. Experiments using IBM Quantum hardware demonstrate that our pulse-based PQC configurations are more capable of solving MaxCut and Chemistry problems compared to a standard configuration. INDEX TERMSQuantum computing, variational quantum algorithms (VQAs), parameterized quantum circuits (PQCs), pulse level control, hamiltonian tomography, barren-plateaus VOLUME 4, 2016 1 This article has been accepted for publication in IEEE Transactions on Quantum Engineering.

Variational Quantum Algorithms (VQAs) have emerged as a powerful class of algorithms that is highly suitable for noisy quantum devices. Therefore, investigating their design has become key in quantum computing research. Previous works have shown that choosing an effective parameterized quantum circuit (PQC) or ansatz for VQAs is crucial to their overall performance, especially on near-term devices. In this paper, we utilize pulse-level access to quantum machines and our understanding of their two-qubit interactions to optimize the design of two-qubit entanglers in a manner suitable for VQAs. Our analysis results show that pulse-optimized ansatze reduce state preparation times by more than half, maintain expressibility relative to standard PQCs, and are more trainable through local cost function analysis. Our algorithm performance results show that in three cases, our PQC configuration outperforms the base implementation. Our algorithm performance results, executed on IBM Quantum hardware, demonstrate that our pulse-optimized PQC configurations are more capable of solving MaxCut and Chemistry problems compared to a standard configuration.

Introduction: Given that obesity is a risk factor for adverse outcomes in COVID-19, bariatric and metabolic surgery (BMS) has become increasingly critical. Computed tomography (chest CT scan) may be a valuable preoperative screening method for BMS candidates during this COVID-19 pandemic.Methods: A prospective, single-center study was conducted in June 2020. Two study cohorts were evaluated: a surgical team group and a BMS patient group. Screening was performed with RT-PCR and a CT scan. The COVID-19 Reporting and Data System (CO-RADS) assessment was used as mandatory COVID-19 screening. Patients classified as category 1 and 2 were considered safe to undergo BMS; category ≥3 surgery was canceled. The BMS patient group was monitored for 28 days after surgery for SARS-CoV-2 infection. Additionally, postoperative complications, adverse effects, and deaths were tracked.Results: The study included 240 participants, comprising the surgical team group (n = 6) and the BMS patient group (n = 234). In total, 213 were female (88.8%), the median age was 40 years, and the median weight and BMI were 111.1 kg and 40.23 kg/m2 respectively. Only CO-RADS category 1 was reported in the surgical team group, while in the BMS patient group, category 1 was reported in 231 participants (98.7%). In the BMS patient group, during the follow-up period, only two participants (0.83%) tested positive for COVID-19 (RT-PCR). No deaths were reported. Conclusion: Chest CT scans are useful for detecting SARS-CoV-2 in patients undergoing BMS, therefore enable healthcare and surgical teams to perform surgeries safely during this COVID-19 pandemic.