155 research outputs found
The OU-ISIR Gait Database Comprising the Large Population Dataset and Performance Evaluation of Gait Recognition
Flexible Integration of Gigahertz Nanomechanical Resonators with a Superconducting Microwave Resonator using a Bonded Flip-Chip Method
We demonstrate strong coupling of gigahertz-frequency nanomechanical
resonators to a frequency-tunable superconducting microwave resonator via a
galvanically bonded flip-chip method. By tuning the microwave resonator with an
external magnetic field, we observe a series of hybridized microwave-mechanical
modes and report coupling strengths of at cryogenic
temperatures. The demonstrated multi-chip approach provides flexible rapid
characterization and simplified fabrication, and could potentially enable
coupling between a variety of quantum systems. Our work represents a step
towards a plug-and-play architecture for building more complex hybrid quantum
systems.Comment: 10 pages, 8 figures. First three authors contributed equally to this
wor
Analysis of arbitrary superconducting quantum circuits accompanied by a Python package: SQcircuit
Superconducting quantum circuits are a promising hardware platform for
realizing a fault-tolerant quantum computer. Accelerating progress in this
field of research demands general approaches and computational tools to analyze
and design more complex superconducting circuits. We develop a framework to
systematically construct a superconducting quantum circuit's quantized
Hamiltonian from its physical description. As is often the case with quantum
descriptions of multicoordinate systems, the complexity rises rapidly with the
number of variables. Therefore, we introduce a set of coordinate
transformations with which we can find bases to diagonalize the Hamiltonian
efficiently. Furthermore, we broaden our framework's scope to calculate the
circuit's key properties required for optimizing and discovering novel qubits.
We implement the methods described in this work in an open-source Python
package SQcircuit. In this manuscript, we introduce the reader to the SQcircuit
environment and functionality. We show through a series of examples how to
analyze a number of interesting quantum circuits and obtain features such as
the spectrum, coherence times, transition matrix elements, coupling operators,
and the phase coordinate representation of eigenfunctions.Comment: 23 pages, 6 figures. Accompanying SQcircuit package on
https://sqcircuit.org
A crystallographic phase transition within the magnetically ordered state of Ce_2Fe_17
X-ray diffraction experiments were performed on polycrystalline and
single-crystal specimens of CeFe at temperatures between 10 K and
300 K. Below = 1182 K, additional weak superstructure
reflections were observed in the antiferromagnetically ordered state. The
superstructure can be described by a doubling of the chemical unit cell along
the direction in hexagonal notation with the same space group as the room-temperature structure. The additional antiferromagnetic
satellite reflections observed in earlier neutron diffraction experiments can
be conclusively related to the appearance of this superstructure.Comment: 8 pages, figures, submitted for publication in Phys. Rev.
Strong dispersive coupling between a mechanical resonator and a fluxonium superconducting qubit
We demonstrate strong dispersive coupling between a fluxonium superconducting
qubit and a 690 megahertz mechanical oscillator, extending the reach of circuit
quantum acousto-dynamics (cQAD) experiments into a new range of frequencies. We
have engineered a qubit-phonon coupling rate of
, and achieved a dispersive interaction that
exceeds the decoherence rates of both systems while the qubit and mechanics are
highly nonresonant (). Leveraging this strong coupling, we
perform phonon number-resolved measurements of the mechanical resonator and
investigate its dissipation and dephasing properties. Our results demonstrate
the potential for fluxonium-based hybrid quantum systems, and a path for
developing new quantum sensing and information processing schemes with phonons
at frequencies below 700 MHz to significantly expand the toolbox of cQAD.Comment: 22 pages, 12 figure
Thermography and thermoregulation of the face
BACKGROUND: Although clinical diagnosis of thermoregulation is gaining in importance there is no consistent evidence on the value of thermography of the facial region. In particular there are no reference values established with standardised methods. METHODS: Skin temperatures were measured in the facial area at 32 fixed measuring sites in 26 health subjects (7–72 years) with the aid of a contact thermograph (Eidatherm). A total of 6 measurements were performed separately for the two sides of the face at intervals of equal lengths (4 hours) over a period of 24 hours. Thermoregulation was triggered by application of a cold stimulus in the region of the ipsilateral ear lobe. RESULTS: Comparison of the sides revealed significant asymmetry of face temperature. The left side of the face showed a temperature that was on the average 0.1°C lower than on the right. No increase in temperature was found following application of the cold stimulus. However, a significant circadian rhythm with mean temperature differences of 0.7°C was observed. CONCLUSION: The results obtained should be seen as an initial basis for compiling an exact thermoprofile of the surface temperature of the facial region that takes into account the circadian rhythm, thus closing gaps in studies on physiological changes in the temperature of the skin of the face
Impacts of introduced species on the biota of an oceanic archipelago: the relative importance of competitive and trophic interactions
Is monitoring of plasma 5-fluorouracil levels in metastatic / advanced colorectal cancer clinically effective? A systematic review
- …