234 research outputs found
Multi-mode ultra-strong coupling in circuit quantum electrodynamics
With the introduction of superconducting circuits into the field of quantum
optics, many novel experimental demonstrations of the quantum physics of an
artificial atom coupled to a single-mode light field have been realized.
Engineering such quantum systems offers the opportunity to explore extreme
regimes of light-matter interaction that are inaccessible with natural systems.
For instance the coupling strength can be increased until it is comparable
with the atomic or mode frequency and the atom can be coupled to
multiple modes which has always challenged our understanding of light-matter
interaction. Here, we experimentally realize the first Transmon qubit in the
ultra-strong coupling regime, reaching coupling ratios of
and we measure multi-mode interactions through a hybridization of the qubit up
to the fifth mode of the resonator. This is enabled by a qubit with 88% of its
capacitance formed by a vacuum-gap capacitance with the center conductor of a
coplanar waveguide resonator. In addition to potential applications in quantum
information technologies due to its small size and localization of electric
fields in vacuum, this new architecture offers the potential to further explore
the novel regime of multi-mode ultra-strong coupling.Comment: 15 pages, 9 figure
Approaching ultra-strong coupling in Transmon circuit-QED using a high-impedance resonator
In this experiment, we couple a superconducting Transmon qubit to a
high-impedance microwave resonator. Doing so leads to a large
qubit-resonator coupling rate , measured through a large vacuum Rabi
splitting of MHz. The coupling is a significant fraction of the
qubit and resonator oscillation frequencies , placing our system close
to the ultra-strong coupling regime ( on resonance).
Combining this setup with a vacuum-gap Transmon architecture shows the
potential of reaching deep into the ultra-strong coupling
with Transmon qubits
In-situ characterization of qubit drive-phase distortions
Reducing errors in quantum gates is critical to the development of quantum
computers. To do so, any distortions in the control signals should be
identified, however, conventional tools are not always applicable when part of
the system is under high vacuum, cryogenic, or microscopic. Here, we
demonstrate a method to detect and compensate for amplitude-dependent phase
changes, using the qubit itself as a probe. The technique is implemented using
a microwave-driven trapped ion qubit, where correcting phase distortions leads
to a three-fold improvement in single-qubit gate error, to attain
state-of-the-art performance benchmarked at error per
Clifford gate
Focusing of quantum gate interactions using dynamical decoupling
In 1995, Cirac and Zoller proposed the first concrete implementation of a
small-scale quantum computer, using laser beams focused to micron spot sizes to
address individual trapped ions in a linear crystal. Here we propose a method
to focus entangling gate interactions, but driven by microwave fields, to
micron-sized zones, corresponding to microwave wavelengths. We
demonstrate the ability to suppress the spin-dependent force using a single
ion, and find the required interaction introduces error
per emulated gate in a single-qubit benchmarking sequence. We model the scheme
for a 17-qubit ion crystal, and find that any pair of ions should be
addressable with an average crosstalk error of
Estudio de isotermas de adsorción de cebada cervecera (<i>Hordeum distichum</i> L.)
Se determinaron las isotermas de adsorción de semillas de cebada cervecera (var. Scarllet) empleando el método gravimétrico estático a diferentes temperaturas (20, 30, 40 y 50ºC) utilizando soluciones de sales saturadas (LiCl, MgCl₂.6H₂O, K₂CO₃, NaBr, NaNO₂, KI, NaNO₃, NaCl, (NH₄)₂SO₄) para proporcionar una actividad de agua para cada temperatura comprendida entre 0.11 y 0.813. Se verificó la presencia de ciclos de histéresis entre las isotermas de adsorción / desorción. Según la clasificación de ciclos de histéresis IUPAC, los ciclos de cebada son del tipo H3. Se utilizaron las ecuaciones modificadas de Henderson, (MHE), Chung-Pfost (MCPE), Halsey (MHaE) y de Oswin (MOE), para evaluar su capacidad de ajustar los datos experimentales de EMC/ERH. La comparación se hizo teniendo en cuenta el error estándar de la estimación (SE), y el coeficiente de determinación (R²) siendo la ecuación modificada de Oswin la más apropiada para modelar las isotermas de adsorción de cebada cervecera var. Scarlett.Centro de Investigación y Desarrollo en Criotecnología de Alimento
Anr and Its Activation by PlcH Activity in Pseudomonas aeruginosa Host Colonization and Virulence
Pseudomonas aeruginosa hemolytic phospholipase C (PlcH) degrades phosphatidylcholine (PC), an abundant lipid in cell membranes and lung surfactant. A ΔplcHR mutant, known to be defective in virulence in animal models, was less able to colonize epithelial cell monolayers and was defective in biofilm formation on plastic when grown in lung surfactant. Microarray analyses found that strains defective in PlcH production had lower levels of Anr-regulated transcripts than the wild type. PC degradation stimulated the Anr regulon in an Anr-dependent manner under conditions where Anr activity was submaximal because of the presence of oxygen. Two PC catabolites, choline and glycine betaine (GB), were sufficient to stimulate Anr activity, and their catabolism was required for Anr activation. The addition of choline or GB to glucose-containing medium did not alter Anr protein levels, growth rates, or respiratory activity, and Anr activation could not be attributed to the osmoprotectant functions of GB. The Δanr mutant was defective in virulence in a mouse pneumonia model. Several lines of evidence indicate that Anr is important for the colonization of biotic and abiotic surfaces in both P. aeruginosa PAO1 and PA14 and that increases in Anr activity resulted in enhanced biofilm formation. Our data suggest that PlcH activity promotes Anr activity in oxic environments and that Anr activity contributes to virulence, even in the acute infection phase, where low oxygen tensions are not expected. This finding highlights the relationships among in vivo bacterial metabolism, the activity of the oxygen-sensitive regulator Anr, and virulence
Monalysin, a Novel ß-Pore-Forming Toxin from the Drosophila Pathogen Pseudomonas entomophila, Contributes to Host Intestinal Damage and Lethality
Pseudomonas entomophila is an entomopathogenic bacterium that infects and kills Drosophila. P. entomophila pathogenicity is linked to its ability to cause irreversible damages to the Drosophila gut, preventing epithelium renewal and repair. Here we report the identification of a novel pore-forming toxin (PFT), Monalysin, which contributes to the virulence of P. entomophila against Drosophila. Our data show that Monalysin requires N-terminal cleavage to become fully active, forms oligomers in vitro, and induces pore-formation in artificial lipid membranes. The prediction of the secondary structure of the membrane-spanning domain indicates that Monalysin is a PFT of the ß-type. The expression of Monalysin is regulated by both the GacS/GacA two-component system and the Pvf regulator, two signaling systems that control P. entomophila pathogenicity. In addition, AprA, a metallo-protease secreted by P. entomophila, can induce the rapid cleavage of pro-Monalysin into its active form. Reduced cell death is observed upon infection with a mutant deficient in Monalysin production showing that Monalysin plays a role in P. entomophila ability to induce intestinal cell damages, which is consistent with its activity as a PFT. Our study together with the well-established action of Bacillus thuringiensis Cry toxins suggests that production of PFTs is a common strategy of entomopathogens to disrupt insect gut homeostasis
Approaching ultrastrong coupling in transmon circuit QED using a high-impedance resonator
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