Realizing topologically ordered states on a quantum processor.

The discovery of topological order has revised the understanding of quantum matter and provided the theoretical foundation for many quantum error­correcting codes. Realizing topologically ordered states has proven to be challenging in both condensed matter and synthetic quantum systems. We prepared the ground state of the toric code Hamiltonian using an efficient quantum circuit on a superconducting quantum processor. We measured a topological entanglement entropy near the expected value of ­ln2 and simulated anyon interferometry to extract the braiding statistics of the emergent excitations. Furthermore, we investigated key aspects of the surface code, including logical state injection and the decay of the nonlocal order parameter. Our results demonstrate the potential for quantum processors to provide insights into topological quantum matter and quantum error correction.

Accurately computing the electronic properties of a quantum ring.

A promising approach to study condensed-matter systems is to simulate them on an engineered quantum platform1-4. However, the accuracy needed to outperform classical methods has not been achieved so far. Here, using 18 superconducting qubits, we provide an experimental blueprint for an accurate condensed-matter simulator and demonstrate how to investigate fundamental electronic properties. We benchmark the underlying method by reconstructing the single-particle band structure of a one-dimensional wire. We demonstrate nearly complete mitigation of decoherence and readout errors, and measure the energy eigenvalues of this wire with an error of approximately 0.01 rad, whereas typical energy scales are of the order of 1 rad. Insight into the fidelity of this algorithm is gained by highlighting the robust properties of a Fourier transform, including the ability to resolve eigenenergies with a statistical uncertainty of 10-4 rad. We also synthesize magnetic flux and disordered local potentials, which are two key tenets of a condensed-matter system. When sweeping the magnetic flux we observe avoided level crossings in the spectrum, providing a detailed fingerprint of the spatial distribution of local disorder. By combining these methods we reconstruct electronic properties of the eigenstates, observing persistent currents and a strong suppression of conductance with added disorder. Our work describes an accurate method for quantum simulation5,6 and paves the way to study new quantum materials with superconducting qubits.

A prospective comparison of two endogenous creatinine clearance testing methods in hospitalized hypertensive gravid women.

OBJECTIVE: Although 24-hour endogenous creatinine clearance testing is common in pregnancies complicated by hypertension, inaccuracies limit its usefulness. We controlled the conditions under which 4-hour endogenous creatinine clearance testing was performed and compared the results with outcomes of 24-hour tests from the same patients. STUDY DESIGN: In 83 women hospitalized with mild hypertension in the third trimester, we measured endogenous creatinine clearance with a 4-hour urine collection during lateral recumbency and supervised oral hydration. This test was paired with a 24-hour test performed immediately thereafter. No restrictions or recommendations regarding ambulation or oral intake were imposed for the 24-hour test. RESULTS: The 4-hour endogenous creatinine clearance value exceeded the 24-hour value in 133 of the 136 paired comparisons (p < 0.0001). Results of the tests from only the 29 patients with multiple paired tests showed more similarity (p < 0.005) among the 4-hour than among the 24-hour clearances. CONCLUSION: The 4-hour endogenous creatinine clearance test, as described, provides a higher and less variable estimate of renal function in hypertensive pregnant women than does the 24-hour test.

[The study of rapid calculation on clearance creatinine rate in normal and epidemic hemorrhagic fever].

Height, weigh, urine volume/24 hours, serum creatinine (Scr) and urine creatinine were measured in 207 normal people and 232 patients with EHF. The clearance Creatinine rate (Ccr) was calculated by 24 hour urine volume method (therapy measure method) and Cockcroft's method (formulation method). The clearance creatinine rates between the two methods compared were significantly positive correlation, but the average values of Ccr in different stages in EHF were significantly different (P < 0.01). The result indicated that Cockcroft's Formulation was not fit for HFRS. According to the difference of Ccr in each stages of EHF, the adjustment values (ad) were presented and used to correct Cockcroft's formulation, thus, the adjusted Cockcroft's formulation could be obtained: Ccr = (140-ad-Age) x W/72 x Scr. In this paper, the Ccr of the adjusted method was compared with that of therapy measure method, the average values calculated by two methods were not different (P > 0.05). The result of 14 EHF Clinic practice demonstrated that between adjustment and practice measured methods were not significantly different. It shows that adjustment method is practical and available and can be used easily by clinic doctors in basic hospital.