Reversing quantum trajectories with analog feedback

We demonstrate the active suppression of transmon qubit dephasing induced by dispersive measurement, using parametric amplification and analog feedback. By real-time processing of the homodyne record, the feedback controller reverts the stochastic quantum phase kick imparted by the measurement on the qubit. The feedback operation matches a model of quantum trajectories with measurement efficiency $\tilde{\eta} \approx 0.5$, consistent with the result obtained by postselection. We overcome the bandwidth limitations of the amplification chain by numerically optimizing the signal processing in the feedback loop and provide a theoretical model explaining the optimization result.Comment: 5 pages, 4 figures, and Supplementary Information (7 figures

Separation of intrinsic dielectric and resistive electrode losses in ferroelectric capacitors at radio frequencies

To analyze the intrinsic dielectric performance of planar high-density capacitors at radio frequencies (RF), the dielectric losses need to be distinguished from the resistive electrode losses. The resistive losses of the electrodes at RF are de-embedded employing a linear regression procedure with partial compensation for distributed effects. We use tunable ferroelectric capacitors with a barium strontium titanate (BST) dielectric with an inner diameter d ≥ 8 μm on a silicon substrate. The de-embedding of the electrode losses has been successfully performed utilizing 1-Port RF measurement data from of an Advantest R3767CG vector network analyzer (VNA) in the frequency range of 10 MHz – 8 GHz

Informe sobre les VII Jornadas Españolas de Documentación, FESABID 2000 (Bilbao, 19-21 d'octubre de 2000)

Aquestes jornades espanyoles de documentació tenen lloc cada dos anys en una localitat diferent d'Espanya, i són organitzades conjuntament per FESABID (Federación Española de Sociedades de Archivística, Biblioteconomía, Documentación y Museística) i l'associació professional de la comunitat autònoma on se celebren. En aquesta ocasió, Bilbao fou la ciutat amfitriona, i ALDEE (Artxibozain, Liburuzain eta Dokumentazainen Euskal Elkartea), una de les associacions professionals que existeixen al País Basc, participà en l'organitzaci

Mast cells in early stages of antigen-induced arthritis in rat knee joints.

The occurrence of mast cells has been investigated in inflamed and control knee joints of rats suffering from antigen-induced arthritis, an animal model of rheumatoid arthritis in man. Rats were immunized with methylated bovine serum albumin (mBSA) followed by an intra-articular injection of mBSA (arthritis, right joints) or saline (control, left joints). Rats developed severe acute synovitis associated with cartilage erosion in the arthritic joints, whereas control joints did not show any noticeable changes. Mast cells were counted in synovial and adjacent tissues in cryostat sections of whole knee joints stained with Toluidine Blue O. The area of the synovium of each knee joint was determined using survey photomicrographs and a morphometer. Both total numbers of mast cells and frequency of mast cells in inflamed synovia were decreased after 1 day after induction of arthritis. The frequency of mast cells remained decreased up to 14 days after induction of arthritis. Morphological indications for degranulation of mast cells were never found in inflamed joints. It is concluded, therefore, that mast cells do not play a significant role in the inflammatory process during the early phase of arthritis

Electrical characterization of thin film ferroelectric capacitors

Tunable capacitors can be used to facilitate the reduction of components in wireless technologies. The tunability of the capacitors is caused by the sensitivity of the relative dielectric constant to a change in polarization with electric field. Thin film ferroelectric MIM capacitors on silicon offer a re-use of electronic circuitry, low tuning voltages, a high capacitance density, a low cost, a presence of bulk acoustic wave resonance(s) and decoupling functionality. The basic operation and measurement principles are outlined. To assess the performance in the microwave frequency range, MIM test structures1, with a barium strontium titanate dielectric, have been successfully processed, and measured. The electrical characterization of tunable capacitors is demonstrated using a 1-Port Advantest R3767CG VNA in the frequency range of 10 MHz – 8 GHz

The trade-off between tuning ratio and quality factor of BaxSr1-xTiO3 MIM capacitors on alumina substrates

Barium strontium titanate with different compositions is deposited using wet-chemical processing on a glass planarization layer, on top of alumina substrates. Three samples were fabricated with BaxSr1-xTiO3 (BST) with the barium content x varying between 0.8 and 1. The poly-crystalline films are 530 ± 12 nm thick. The optimization in terms of permittivity and quality factor is explored for barium strontium titanate on alumina substrates. The trade-off between the permittivity and quality factor (at 1 GHz) is investigated. Our results show that wet-chemical processing on glass-planarized alumina results in a quality factor between 21–27 at 1 GHz and a tuning ratio from 1.8 to 2.0 at an electric field of 0.4 MV/cm