328 research outputs found
Dynamics of a qubit while simultaneously monitoring its relaxation and dephasing
Decoherence originates from the leakage of quantum information into external
degrees of freedom. For a qubit the two main decoherence channels are
relaxation and dephasing. Here, we report an experiment on a superconducting
qubit where we retrieve part of the lost information in both of these channels.
We demonstrate that raw averaging the corresponding measurement records
provides a full quantum tomography of the qubit state where all three
components of the effective spin-1/2 are simultaneously measured. From single
realizations of the experiment, it is possible to infer the quantum
trajectories followed by the qubit state conditioned on relaxation and/or
dephasing channels. The incompatibility between these quantum measurements of
the qubit leads to observable consequences in the statistics of quantum states.
The high level of controllability of superconducting circuits enables us to
explore many regimes from the Zeno effect to underdamped Rabi oscillations
depending on the relative strengths of driving, dephasing and relaxation.Comment: Supplemental videos can be found at
http://physinfo.fr/publications/Ficheux1710.html and supplemental information
can be found as an ancillary file on arxi
RTEL4I (Real Time Embedded Linux for Industries)
International audienceRTEL4I project deals about creating a free IDE (Integrated Development Environment) in order to achieve migration from proprietary hard real-time embedded systems (RTOS) to Linux environment easily. Of course same IDE could be used for creating native real-time applications for Linux. IDE runs on Linux but is âdistribution agnosticsâ as it just needs standard tools (such as GCC, JRE, ...) which are available in most recent (and decent) Linux distributions
Dynamique et génétique des populations de cistude d'Europe Emys orbicularis
Dispersal, characterized by the movements of individuals in space leading to gene flows, allows populations to connect. The study of dispersal has become of essential importance to predict the consequences of global changes on the population structures and dynamics. Species with limited dispersal, such as chelonians, are particularly threatened by these phenomena. Our study aimed at analyzing the dispersal of the European pond turtle (Emys orbicularis), in decline in Europe, in a habitats fragmentation context and determining the causes of this behavior through analysis of population dynamics and genetics. Our results show, firstly, that the slow generation time in Emys orbicularis (about 12 years) may slow the genetic erosion by drift. This slow erosion is accentuated with large populations such as Kerkini populations, even with a strong fragmentation. On the other hand, selection would have favored philopatry in females in habitats with few nesting site and deers, because they have the advantage of territoriality. In contrast, the cost of dispersal decreases for males because this behavior allows inbreeding avoidance. The European pond turtles seem very sensitive to intra-specific competition. Indeed, the relaxation of adult density-dependence allows for a significant recruitment of juveniles. This dynamic promotes an unexpected rapid response of the population after a major disturbance, because chelonians are long-lived animals with a late age of first reproduction and very high generation time, therefore, the time of resilience to perturbations is also expected to be high.La dispersion, caractĂ©risĂ©e par les mouvements dâindividus dans lâespace conduisant Ă la production dâun flux de gĂšnes, permet la connectivitĂ© des populations. LâĂ©tude de la dispersion est devenue dâune importance primordiale pour prĂ©dire les consĂ©quences des changements globaux sur la structure et la dynamique des populations. Les espĂšces Ă dispersion limitĂ©es, comme les chĂ©loniens, sont particuliĂšrement menacĂ©es par ces phĂ©nomĂšnes. Cette Ă©tude se propose dâanalyser la dispersion chez la Cistude dâEurope (Emys orbicularis), en rĂ©gression en Europe, dans un contexte de fragmentation dâhabitats et de dĂ©terminer les causes de ce comportement via lâanalyse de la dynamique et de la gĂ©nĂ©tique des populations. Nos rĂ©sultats montrent, dâune part, que les temps de gĂ©nĂ©rations lents chez les cistudes (environ 12 ans) peuvent ralentir les phĂ©nomĂšnes dâĂ©rosion gĂ©nĂ©tique par dĂ©rive. Cette Ă©rosion lente est accentuĂ©e en prĂ©sence de grandes populations mĂȘme en milieu trĂšs fragmentĂ©. Dâautre part, la sĂ©lection aurait favorisĂ©e la philopatrie chez les femelles cistudes dans les milieux peu riches en site de ponte et de faible densitĂ© dâindividus car elles ont un avantage Ă la territorialitĂ©. A lâinverse, le coĂ»t Ă la dispersion diminuerait pour les mĂąles car ce comportement Ă©viterait la consanguinitĂ©. Les cistudes semblent donc trĂšs sensibles Ă la compĂ©tition intra-spĂ©cifique. En effet, la relaxation de la densitĂ©-dĂ©pendance des adultes permet un recrutement important de juvĂ©niles. Cette dynamique favoriserait une rĂ©cupĂ©ration rapide des effectifs aprĂšs une importante perturbation, ce qui est surprenant pour une espĂšce longĂ©vive dont les temps de rĂ©silience sont supposĂ©s lents
Induction of Human Immunodeficiency Virus (HIV-1) Envelope Specific Cell-Mediated Immunity by a Non-Homologous Synthetic Peptide
Peer reviewed: YesNRC publication: Ye
Analysis of hepatitis C virus RNA dimerization and coreâRNA interactions
The core protein of hepatitis C virus (HCV) has been shown previously to act as a potent nucleic acid chaperone in vitro, promoting the dimerization of the 3âČ-untranslated region (3âČ-UTR) of the HCV genomic RNA, a process probably mediated by a small, highly conserved palindromic RNA motif, named DLS (dimer linkage sequence) [G. Cristofari, R. Ivanyi-Nagy, C. Gabus, S. Boulant, J. P. Lavergne, F. Penin and J. L. Darlix (2004) Nucleic Acids Res., 32, 2623â2631]. To investigate in depth HCV RNA dimerization, we generated a series of point mutations in the DLS region. We find that both the plus-strand 3âČ-UTR and the complementary minus-strand RNA can dimerize in the presence of core protein, while mutations in the DLS (among them a single point mutation that abolished RNA replication in a HCV subgenomic replicon system) completely abrogate dimerization. Structural probing of plus- and minus-strand RNAs, in their monomeric and dimeric forms, indicate that the DLS is the major if not the sole determinant of UTR RNA dimerization. Furthermore, the N-terminal basic amino acid clusters of core protein were found to be sufficient to induce dimerization, suggesting that they retain full RNA chaperone activity. These findings may have important consequences for understanding the HCV replicative cycle and the genetic variability of the virus
Calibration of Drive Non-Linearity for Arbitrary-Angle Single-Qubit Gates Using Error Amplification
The ability to execute high-fidelity operations is crucial to scaling up
quantum devices to large numbers of qubits. However, signal distortions
originating from non-linear components in the control lines can limit the
performance of single-qubit gates. In this work, we use a measurement based on
error amplification to characterize and correct the small single-qubit rotation
errors originating from the non-linear scaling of the qubit drive rate with the
amplitude of the programmed pulse. With our hardware, and for a 15-ns pulse,
the rotation angles deviate by up to several degrees from a linear model. Using
purity benchmarking, we find that control errors reach , which
accounts for half of the total gate error. Using cross-entropy benchmarking, we
demonstrate arbitrary-angle single-qubit gates with coherence-limited errors of
and leakage below . While the exact
magnitude of these errors is specific to our setup, the presented method is
applicable to any source of non-linearity. Our work shows that the
non-linearity of qubit drive line components imposes a limit on the fidelity of
single-qubit gates, independent of improvements in coherence times, circuit
design, or leakage mitigation when not corrected for
Structural and functional stabilization of bacteriophage particles within the aqueous core of a W/O/W multiple emulsion: a potential biotherapeutic system for the inhalational treatment of bacterial pneumonia
The increase of antibiotic-resistant bacteria is growing every day, most likely associated with the indiscriminate use of these antimicrobials or even with evolutionary adaptability of bacteria to their environment. This situation brings a need to develop new alternatives to conventional antibiotics, and thus the application of strictly lytic bacteriophages has been proposed as an alternative (or complement) to the former, allowing release of the natural predators of bacteria directly where they are needed the most: the infection site. The main advantages of bacteriophages to treat infections is the maintenance of a high concentration of bacteriophage particles in the action site while any viable target bacteria still exist, coupled to the production of enzymes that hydrolyze the polymeric matrix of bacterial biofilms promoting penetration and antibacterial action. In the research effort entertained herein, the potential for protection and stabilization of strictly lytic bacteriophages with broad spectrum capable of infecting Pseudomonas aeruginosa, so as to maintain their structure and functionality, was investigated via encapsulation within the aqueous-core of lipid nanodroplets integrating a W/O/W multiple emulsion system, aiming at developing isotonic derivative solutions thereof for administration by nebulization.Project funding by FAPESP (SĂŁo Paulo, Brazil; Refs. No. 2013/ 03181-6 (Project PneumoPhageKill), 2016/08884-3 (Project PneumoPhageColor) and 2016/12234-4 (Project TransAppIL)), is hereby gratefully acknowledged. This work also received support from CNPq, in the form of a Research Productivity (PQ)fellowship granted to Victor M. BalcĂŁo (Ref. No. 306113/2014-7). The authors are grateful to the LME facility at LNNano/CNPEM (Campinas, Brazil) for the use of the TEM microscope. The authors have no conïŹicts of interest whatsoever to declare.info:eu-repo/semantics/publishedVersio
- âŠ