Removing leakage-induced correlated errors in superconducting quantum error correction.

Quantum computing can become scalable through error correction, but logical error rates only decrease with system size when physical errors are sufficiently uncorrelated. During computation, unused high energy levels of the qubits can become excited, creating leakage states that are long-lived and mobile. Particularly for superconducting transmon qubits, this leakage opens a path to errors that are correlated in space and time. Here, we report a reset protocol that returns a qubit to the ground state from all relevant higher level states. We test its performance with the bit-flip stabilizer code, a simplified version of the surface code for quantum error correction. We investigate the accumulation and dynamics of leakage during error correction. Using this protocol, we find lower rates of logical errors and an improved scaling and stability of error suppression with increasing qubit number. This demonstration provides a key step on the path towards scalable quantum computing.

Effect of pre-deposition RF plasma etching on wafer surface morphology and crystal orientation of piezoelectric AlN thin films.

In this work, we describe the design and operation of a planarized capacitively coupled RF plasma module and investigate the effects of non-reactive RF plasma etching on Si (100) wafer surface morphology and crystal orientation of Al bottom electrodes and subsequently deposited AlN films. To ensure formation of highly (111) textured Al electrode, a thin 25-nm AlN seed layer was grown before the Al deposition. The seed layer's orientation efficiency improved with increasing the RF power from 70 to 300 W and resulted in narrowing the Al (111) rocking curves. AFM and XRD data have shown that crystal orientations of both the electrode and reactively sputtered AlN film are considerably improved when the substrate micro roughness is reduced from an ordinary level of a few nanometers to atomic level corresponding to root mean square roughness as low as about 0.2 to 0.3 nm. The most perfectly crystallized film stacks of 100-nm Al and 500-nm AlN were obtained in this work using etching in Ar plasma optimized to create an atomically smooth, epi-ready Si surface morphology that enables superior AlN seed layer nucleation conditions. X-ray rocking curves around the Al (111) and AlN (0002) diffraction peaks exhibited extremely low FWHM values of 0.68° and 1.05°, respectively.

[Comparative histomorphological analysis of bone fragments consolidation in compression and non-compression mandible osteosynthesis].

On experimentally produced model of mandible fractures (on 18 rabbits) the efficacy of compression osteosynthesis was compared with fixation by usual plates (non-compression osteosynthesis). As was shown by histological study and morphometrical analysis of tissue structures from the region of experimentally isolated in rabbit mandible bone fragments fixed by microdevices for compression and non-compression osteosynthesis in cases of compression osteosynthesis if compared with non-compression osteosynthesis at the experimental terms of 2, 3 and 4 months more intensive new formation and secondary rebuilding of bone tissue with its compactification in the region of cortical layer happened. Histological study and morphometrical analysis of histological pictures showed that reparative osteosynthesis processes were activated in cases of compression osteogenesis not only in cortical but also in sponge layer that together with contact enforcing of the edge of experimentally isolated bone fragment with maternal bone and bone splinters fixation strengthening stipulated for integral positive effect in the form of bone integrity restoration acceleration. In case of non-compression osteosynthesis the processes of reparative bone formation were observed mainly in cortical layer region, in sponge layers they were expressed poorly.

[Use of local UHF hyperthermia and CO(2) laser in treatment of cancer of the lip, lingual mucosa, and bottom of the oral cavity]. / Primenenie lokal'noi SVCh-gipertermii i CO(2)-lazera v lechenii raka guby, slizistoi obolochki iazyka i dna polosti rta.

A total of 424 patients with cancer of the lips, lingual mucosa, and bottom of the oral cavity were treated using local hyperthermia and CO(2) laser. The best results were attained in patients with the disease stage T1N0M0-T2N0M0: 5-year survival without local relapses and metastases was 43.3-58.5% in this group.

[Sex steroid hormone receptors in the cytosolic fraction of cancer and leukoplakia of the oral mucosa]. / Retseptory polovykh steroidnykh gormonov v tsitozol'noi fraktsii raka i leikoplakii slizistoi obolochki polosti rta.

The paper deals with the studies of sexual steroidal hormone receptors in the tumor cytosolic fraction in 37 patients with squamous cell carcinoma and in 18 patients from leukoplakia foci in the oral mucosa. One or two types of androgen and estrogen receptors were detected in the tumor cytosolic fraction in most female (75%) and male (62%) patients with squamous cell carcinoma. The detection rate and the mean values of androgen and estrogen receptors in squamous cell carcinoma of the oral mucosa were associated with sex, age, disease stage, type of growth and site of a tumor. Detection and levels of androgen and estrogen receptors in the leukoplakia foci of the oral mucosa depended on the age of patients. Cytoplasmic estrogen receptors (50%) and oral mucosal squamous cell cancer (34.4%) were much more encountered in the foci of leukoplakia and their mean levels tended to increase. The mechanism of action of sexual steroids on normal and tumor target cells, the role of androgens and estrogens in the pathogenesis of oral mucosal carcinoma and leukoplakia, and possible methods of endocrine therapy for these diseases are discussed.