| 1. |
- Blomberg, Lars G., et al.
(author)
-
EMMA - the electric and magnetic monitor of the aurora on Astrid-2
- 2004
-
In: Annales Geophysicae. - : Copernicus GmbH. - 0992-7689 .- 1432-0576. ; 22:1, s. 115-123
-
Journal article (peer-reviewed)abstract
- The Astrid-2 mission has dual primary objectives. First, it is an orbiting instrument platform for studying auroral electrodynamics. Second, it is a technology demonstration of the feasibility of using micro-satellites for innovative space plasma physics research. The EMMA instrument, which we discuss in the present paper, is designed to provide simultaneous sampling of two electric and three magnetic field components up to about 1 kHz. The spin plane components of the electric field are measured by two pairs of opposing probes extended by wire booms with a separation distance of 6.7 m. The probes have titanium nitride (TiN) surfaces. which has proved to be a material with excellent properties for providing good electrical contact between probe and plasma. The wire booms are of a new design in which the booms in the stowed position are wound around the exterior of the spacecraft body. The boom system was flown for the first time on this mission and worked flawlessly. The magnetic field is measured by a tri-axial fluxgate sensor located at the tip of a rigid. hinged boom extended along the spacecraft spin axis and facing away from the Sun. The new advanced-design fluxgate magnetometer uses digital signal processors for detection and feedback, thereby reducing the analogue circuitry to a minimum. The instrument characteristics as well as a brief review of the science accomplished and planned are presented.
|
|
| 2. |
|
|
| 3. |
- Chen, Liangyu, 1994, et al.
(author)
-
Transmon qubit readout fidelity at the threshold for quantum error correction without a quantum-limited amplifier
- 2023
-
In: npj Quantum Information. - : Springer Science and Business Media LLC. - 2056-6387. ; 9:1
-
Journal article (peer-reviewed)abstract
- High-fidelity and rapid readout of a qubit state is key to quantum computing and communication, and it is a prerequisite for quantum error correction. We present a readout scheme for superconducting qubits that combines two microwave techniques: applying a shelving technique to the qubit that reduces the contribution of decay error during readout, and a two-tone excitation of the readout resonator to distinguish among qubit populations in higher energy levels. Using a machine-learning algorithm to post-process the two-tone measurement results further improves the qubit-state assignment fidelity. We perform single-shot frequency-multiplexed qubit readout, with a 140 ns readout time, and demonstrate 99.5% assignment fidelity for two-state readout and 96.9% for three-state readout–without using a quantum-limited amplifier.
|
|
| 4. |
- Fadavi Roudsari, Anita, 1978, et al.
(author)
-
Three-wave mixing traveling-wave parametric amplifier with periodic variation of the circuit parameters
- 2023
-
In: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 122:5
-
Journal article (peer-reviewed)abstract
- We report on the implementation of a near-quantum-limited, traveling-wave parametric amplifier that uses three-wave mixing (3WM). To favor amplification by 3WM, we use superconducting nonlinear asymmetric inductive element (SNAIL) loops, biased with a dc magnetic flux. In addition, we equip the device with dispersion engineering features to create a stopband at the second harmonic of the pump and suppress the propagation of the higher harmonics that otherwise degrade the amplification. With a chain of 440 SNAILs, the amplifier provides up to 20 dB gain and a 3-dB bandwidth of 1 GHz. The added noise by the amplifier is found to be less than one photon.
|
|
| 5. |
- Gisselsson-Solén, Marie, et al.
(author)
-
The Binax NOW test as a tool for diagnosis of severe acute otitis media and associated complications
- 2007
-
In: Journal of Clinical Microbiology. - 0095-1137 .- 1098-660X. ; 45:9, s. 3003-3007
-
Journal article (peer-reviewed)abstract
- The diagnosis of acute otitis media (AOM) is often difficult, depending heavily on the experience and skills of the examiner. However, it is important to identify episodes of AOM that involve the risk of complications and to treat these episodes appropriately. The present study was performed in order to evaluate the use of a rapid antigen assay for Streptococcus pneumoniae, the Binax NOW test, as a diagnostic tool in patients with severe AOM and associated complications. The study included 70 patients with 74 episodes of AOM, 18 of them with complications. Cultures, Binax NOW tests, and a PCR assay were performed on nasopharyngeal secretions, middle ear fluid, and in some cases mastoid bone, cerebrospinal fluid, and urine. According to culture and PCR of the middle ear fluid, 30 (41%) of the episodes were caused by S. pneumoniae. The Binax NOW test was positive in 24 of these episodes (80%). It identified pneumococcal AOM independent of antibiotic treatment, and it was easily adapted to bone tissue. The test yielded sensitivity, specificity, and positive and negative predictive values for middle ear specimens of 85%, 100%, 100%, and 89%, respectively. The corresponding positive and negative values for predicting the bacterial etiology with nasopharyngeal secretions were 51% and 75%. This study showed that the Binax NOW test is a useful diagnostic tool for patients with severe AOM with or without complications.
|
|
| 6. |
- Grigoras, K., et al.
(author)
-
Qubit-Compatible Substrates With Superconducting Through-Silicon Vias
- 2022
-
In: IEEE Transactions on Quantum Engineering. - 2689-1808. ; 3
-
Journal article (peer-reviewed)abstract
- We fabricate and characterize superconducting through-silicon vias and electrodes suitable for superconducting quantum processors. We measure internal quality factors of a million for test resonators excited at single-photon levels, on chips with superconducting vias used to stitch ground planes on the front and back sides of the chips. This resonator performance is on par with the state of the art for silicon-based planar solutions, despite the presence of vias. Via stitching of ground planes is an important enabling technology for increasing the physical size of quantum processor chips, and is a first step toward more complex quantum devices with three-dimensional integration.
|
|
| 7. |
- Kosen, Sandoko, 1991, et al.
(author)
-
Building blocks of a flip-chip integrated superconducting quantum processor
- 2022
-
In: Quantum Science and Technology. - : IOP Publishing. - 2058-9565. ; 7:3
-
Journal article (peer-reviewed)abstract
- We have integrated single and coupled superconducting transmon qubits into flip-chip modules. Each module consists of two chips-one quantum chip and one control chip-that are bump-bonded together. We demonstrate time-averaged coherence times exceeding 90 mu s, single-qubit gate fidelities exceeding 99.9%, and two-qubit gate fidelities above 98.6%. We also present device design methods and discuss the sensitivity of device parameters to variation in interchip spacing. Notably, the additional flip-chip fabrication steps do not degrade the qubit performance compared to our baseline state-of-the-art in single-chip, planar circuits. This integration technique can be extended to the realisation of quantum processors accommodating hundreds of qubits in one module as it offers adequate input/output wiring access to all qubits and couplers.
|
|
| 8. |
- Norman, Christer, et al.
(author)
-
STRAMA håller fast vid Otitkonsensus
- 2007
-
In: Läkartidningen. - 0023-7205 .- 1652-7518. ; 104:26-27, s. 1996-1997
-
Journal article (other academic/artistic)abstract
- [STRAMA sticks to the otitis consensus]
|
|
| 9. |
|
|
| 10. |
- Osman, Amr, 1993, et al.
(author)
-
Mitigation of frequency collisions in superconducting quantum processors
- 2023
-
In: Physical Review Research. - 2643-1564. ; 5:4
-
Journal article (peer-reviewed)abstract
- The reproducibility of qubit parameters is a challenge for scaling up superconducting quantum processors. Signal cross talk imposes constraints on the frequency separation between neighboring qubits. The frequency uncertainty of transmon qubits arising from the fabrication process is attributed to deviations in the Josephson junction area, tunnel barrier thickness, and the qubit shunt capacitor. We decrease the sensitivity to these variations by fabricating larger Josephson junctions and reduce the wafer-level standard deviation in resistance down to 2%. We characterize 32 identical transmon qubits and demonstrate the reproducibility of the qubit frequencies with a 40 MHz standard deviation (i.e., 1%) with qubit quality factors exceeding 2 million. We perform two-level-system (TLS) spectroscopy and observe no significant increase in the number of TLSs causing qubit relaxation. We further show by simulation that for our parametric-gate architecture, and accounting only for errors caused by the uncertainty of the qubit frequency, we can scale up to 100 qubits with an average of only three collisions between quantum-gate transition frequencies, assuming 2% cross talk and 99.9% target gate fidelity.
|
|
