48 research outputs found
Single-photon Resolved Cross-Kerr Interaction for Autonomous Stabilization of Photon-number States
Quantum states can be stabilized in the presence of intrinsic and
environmental losses by either applying active feedback conditioned on an
ancillary system or through reservoir engineering. Reservoir engineering
maintains a desired quantum state through a combination of drives and designed
entropy evacuation. We propose and implement a quantum reservoir engineering
protocol that stabilizes Fock states in a microwave cavity. This protocol is
realized with a circuit quantum electrodynamics platform where a Josephson
junction provides direct, nonlinear coupling between two superconducting
waveguide cavities. The nonlinear coupling results in a single photon resolved
cross-Kerr effect between the two cavities enabling a photon number dependent
coupling to a lossy environment. The quantum state of the microwave cavity is
discussed in terms of a net polarization and is analyzed by a measurement of
its steady state Wigner function.Comment: 8 pages, 6 figure
Implementing and characterizing precise multi-qubit measurements
There are two general requirements to harness the computational power of
quantum mechanics: the ability to manipulate the evolution of an isolated
system and the ability to faithfully extract information from it. Quantum error
correction and simulation often make a more exacting demand: the ability to
perform non-destructive measurements of specific correlations within that
system. We realize such measurements by employing a protocol adapted from [S.
Nigg and S. M. Girvin, Phys. Rev. Lett. 110, 243604 (2013)], enabling real-time
selection of arbitrary register-wide Pauli operators. Our implementation
consists of a simple circuit quantum electrodynamics (cQED) module of four
highly-coherent 3D transmon qubits, collectively coupled to a high-Q
superconducting microwave cavity. As a demonstration, we enact all seven
nontrivial subset-parity measurements on our three-qubit register. For each we
fully characterize the realized measurement by analyzing the detector
(observable operators) via quantum detector tomography and by analyzing the
quantum back-action via conditioned process tomography. No single quantity
completely encapsulates the performance of a measurement, and standard figures
of merit have not yet emerged. Accordingly, we consider several new fidelity
measures for both the detector and the complete measurement process. We measure
all of these quantities and report high fidelities, indicating that we are
measuring the desired quantities precisely and that the measurements are highly
non-demolition. We further show that both results are improved significantly by
an additional error-heralding measurement. The analyses presented here form a
useful basis for the future characterization and validation of quantum
measurements, anticipating the demands of emerging quantum technologies.Comment: 10 pages, 5 figures, plus supplemen
Demonstration of Universal Parametric Entangling Gates on a Multi-Qubit Lattice
We show that parametric coupling techniques can be used to generate selective
entangling interactions for multi-qubit processors. By inducing coherent
population exchange between adjacent qubits under frequency modulation, we
implement a universal gateset for a linear array of four superconducting
qubits. An average process fidelity of is estimated for
three two-qubit gates via quantum process tomography. We establish the
suitability of these techniques for computation by preparing a four-qubit
maximally entangled state and comparing the estimated state fidelity against
the expected performance of the individual entangling gates. In addition, we
prepare an eight-qubit register in all possible bitstring permutations and
monitor the fidelity of a two-qubit gate across one pair of these qubits.
Across all such permutations, an average fidelity of
is observed. These results thus offer a path to a scalable architecture with
high selectivity and low crosstalk
A Mitochondria-Dependent Pathway Mediates the Apoptosis of GSE-Induced Yeast
Grapefruit seed extract (GSE), which has powerful anti-fungal activity, can induce apoptosis in S. cerevisiae. The yeast cells underwent apoptosis as determined by testing for apoptotic markers of DNA cleavage and typical chromatin condensation by Terminal Deoxynucleotidyl Transferase–mediated dUTP Nick End Labeling (TUNEL) and 4,6′-diaminidino-2-phenylindole (DAPI) staining and electron microscopy. The changes of ΔΨmt (mitochondrial transmembrane potential) and ROS (reactive oxygen species) indicated that the mitochondria took part in the apoptotic process. Changes in this process detected by metabonomics and proteomics revealed that the yeast cells tenaciously resisted adversity. Proteins related to redox, cellular structure, membrane, energy and DNA repair were significantly increased. In this study, the relative changes in the levels of proteins and metabolites showed the tenacious resistance of yeast cells. However, GSE induced apoptosis in the yeast cells by destruction of the mitochondrial 60 S ribosomal protein, L14-A, and prevented the conversion of pantothenic acid to coenzyme A (CoA). The relationship between the proteins and metabolites was analyzed by orthogonal projections to latent structures (OPLS). We found that the changes of the metabolites and the protein changes had relevant consistency
Neonatal Cardiopulmonary Bypass Circuit Blood Prime Quality Analysis
Blood-primed cardiopulmonary bypass circuits are frequently necessary to achieve safe support during pediatric open-heart surgery. Literature is lacking regarding suitable prime constituents or methods for achieving a physiologically appropriate blood-primed circuit. We examined the chemistry and hematology of neonatal blood-primed circuits from the conclusion of the priming procedure until the initiation of bypass. Base deficit/excess, pH, pO2, pCO2, HCO3, glucose, sodium, potassium, calcium, hematocrit, lactate, and osmolality were analyzed. Any deviation over time from the original prime value was compared for significance. Statistically significant changes were found between T0 and all time points for all parameters, except for pH and pO2 out to 1 hour. Among all parameters, various rates of change were observed. Although most changes in the parameters were found to be statistically significant, those changes may not be clinically significant based on clinician interpretation. Attention to the prime quality beyond the immediate post-priming period may be beneficial. Should the time period between validation of the prime quality and initiation of bypass be extended, it may be advisable to reevaluate the prime quality
Development of the Adult ECMO Specialist Certification Examination
The American Society of Extracorporeal Technology Board of Directors, consistent with the American Society of Extracorporeal Technology’s safe patient care improvement mission, charged the International Board of Blood Management to write a knowledge and skill certification examination for healthcare personnel employed as adult extracorporeal membrane oxygenation (ECMO) specialists. Nineteen nationally recognized ECMO subject-matter experts were selected to complete the examination development. A job analysis was performed, yielding a job description and examination plan focused on 16 job categories. Multiple-choice test items were created and validated. Qualified ECMO specialists were identified to complete a pilot examination and both pre- and post-examination surveys. The examination item difficulty and candidate performance were ranked and matched using Rasch methodology. Candidates’ examination scores were compared with their profession, training, and experience as ECMO specialists. The 120-item pilot examination form ranked 76 ECMO specialist candidates consistent with their licensure, ECMO training, and clinical experience. Forty-three registered nurses, 28 registered respiratory therapists, four certified clinical perfusionists, and one physician assistant completed the pilot examination process. Rasch statistics revealed examination reliability coefficients of .83 for candidates and .88 for test items. Candidates ranked the appropriateness for examination items consistent with the item content, difficulty, and their personal examination score. The pilot examination pass rate was 80%. The completed examination product scheduled for enrollment in March 2020 includes 100 verified test items with an expected pass rate of 84% at a cut score of 67%. The online certification examination based on a verified job analysis provides an extramural assessment that ranks minimally prepared ECMO specialists’ knowledge, skills, and abilities (KSA) consistent with safe ECMO patient care and circuit management. It is anticipated that ECMO facilities and ECMO service providers will incorporate the certification examination as part of their process improvement, safety, and quality assurance plans