Reference-State Error Mitigation: A Strategy for High Accuracy Quantum Computation of Chemistry

Decoherence and gate errors severely limit the capabilities of state-of-the-art quantum computers. This work introduces a strategy for reference-state error mitigation (REM) of quantum chemistry that can be straightforwardly implemented on current and near-term devices. REM can be applied alongside existing mitigation procedures, while requiring minimal postprocessing and only one or no additional measurements. The approach is agnostic to the underlying quantum mechanical ansatz and is designed for the variational quantum eigensolver. Up to two orders-of-magnitude improvement in the computational accuracy of ground state energies of small molecules (H2, HeH+, and LiH) is demonstrated on superconducting quantum hardware. Simulations of noisy circuits with a depth exceeding 1000 two-qubit gates are used to demonstrate the scalability of the method

Tacrolimus and Mycophenolate Mofetil as Second-Line Therapies for Pediatric Patients with Autoimmune Hepatitis

Background: We studied the efficacy and safety of mycophenolate mofetil (MMF) and tacrolimus as second-line therapy in pediatric patients with autoimmune hepatitis (AIH) who were intolerant or non-responders to standard therapy (corticosteroid and azathioprine). Patients and Methods: We performed a retrospective study of data from 13 centers in Europe, USA, and Canada. Thirty-eight patients (< 18\ua0years old) who received second-line therapy (18 MMF and 20 tacrolimus), for a median of 72\ua0months (range 8\u2013182) were evaluated. Patients were categorized into two groups: Group 1 (n = 17) were intolerant to corticosteroid or azathioprine, and group 2 (n = 21) were non-responders to standard therapy. Results: Overall complete response rates were similar in patients treated with MMF and tacrolimus (55.6 vs. 65%, p = 0.552). In group 1, MMF and tacrolimus maintained a biochemical remission in 88.9 and 87.5% of patients, respectively (p = 0.929). More patients in group 2 given tacrolimus compared to MMF had a complete response, but the difference was not statistically significant (50.0 vs. 22.2%, p = 0.195). Biochemical remission was achieved in 71.1% (27/38) of patients by tacrolimus and/or MMF. Decompensated cirrhosis was more commonly seen in MMF and/or tacrolimus non-responders than in responders (45.5 vs. 7.4%, p = 0.006). Five patients who received second-line therapy (2 MMF and 3 tacrolimus) developed side effects that led to therapy withdrawal. Conclusions: Long-term therapy with MMF or tacrolimus was generally well tolerated by pediatric patients with AIH. Both MMF and tacrolimus had excellent efficacy in patients intolerant to corticosteroid or azathioprine. Tacrolimus might be more effective than MMF in patients failing previous therapy