Trapped electron coupled to superconducting devices

We propose to couple a trapped single electron to superconducting structures located at a variable distance from the electron. The electron is captured in a cryogenic Penning trap using electric fields and a static magnetic field in the Tesla range. Measurements on the electron will allow investigating the properties of the superconductor such as vortex structure, damping and decoherence. We propose to couple a superconducting microwave resonator to the electron in order to realize a circuit QED-like experiment, as well as to couple superconducting Josephson junctions or superconducting quantum interferometers (SQUIDs) to the electron. The electron may also be coupled to a vortex which is situated in a double well potential, realized by nearby pinning centers in the superconductor, acting as a quantum mechanical two level system that can be controlled by a transport current tilting the double well potential. When the vortex is trapped in the interferometer arms of a SQUID, this would allow its detection both by the SQUID and by the electron.Comment: 13 pages, 5 figure

Life after charge noise: recent results with transmon qubits

We review the main theoretical and experimental results for the transmon, a superconducting charge qubit derived from the Cooper pair box. The increased ratio of the Josephson to charging energy results in an exponential suppression of the transmon's sensitivity to 1/f charge noise. This has been observed experimentally and yields homogeneous broadening, negligible pure dephasing, and long coherence times of up to 3 microseconds. Anharmonicity of the energy spectrum is required for qubit operation, and has been proven to be sufficient in transmon devices. Transmons have been implemented in a wide array of experiments, demonstrating consistent and reproducible results in very good agreement with theory.Comment: 6 pages, 4 figures. Review article, accepted for publication in Quantum Inf. Pro

Optical suppression of tilt-to-length coupling in the LISA long-arm interferometer

The arm length and the isolation in space enable the Laser Interferometer Space Antenna (LISA) to probe for signals unattainable on the ground, opening a window to the subhertz gravitational-wave universe. The coupling of unavoidable angular spacecraft jitter into the longitudinal displacement measurement, an effect known as tilt-to-length (TTL) coupling, is critical for realizing the required sensitivity of picometer / √ Hz . An ultrastable interferometer test bed has been developed in order to investigate this issue and validate mitigation strategies in a setup representative of LISA and in this paper it is operated in the long-arm interferometer configuration. The test bed is fitted with a flat-top beam generator to simulate the beam received by a LISA spacecraft. We demonstrate a reduction of TTL coupling between this flat-top beam and a Gaussian reference beam via the introduction of two- and four-lens imaging systems. TTL coupling factors below ± 25 μ m / rad for beam tilts within ± 300 μ rad are obtained by careful optimization of the system. Moreover, we show that the additional TTL coupling due to lateral-alignment errors of elements of the imaging system can be compensated by introducing lateral shifts of the detector and vice versa. These findings help validate the suitability of this noise-reduction technique for the LISA long-arm interferometer

Centrality Dependence Of The Pseudorapidity Density Distribution For Charged Particles In Pb-pb Collisions At √snn=2.76tev

7264/Mai61062

Elliptic flow of identified hadrons in Pb-Pb collisions at 1asNN = 2.76 TeV

The elliptic flow coefficient (v2) of identified particles in Pb-Pb collisions at 1asNN = 2.76 TeV was measured with the ALICE detector at the Large Hadron Collider (LHC). The results were obtained with the Scalar Product method, a two-particle corre- lation technique, using a pseudo-rapidity gap of | 06\u3b7| > 0.9 between the identified hadron under study and the reference particles. The v2 is reported for \u3c0\ub1, K\ub1, K0S, p+p, \u3c6, \u39b+\u39b, \u39e 12+\u39e+ and \u3a9 12+\u3a9+ in several collision centralities. In the low transverse momentum (pT) region, pT 3 GeV/c

The quest to resolve recent radiations: Plastid phylogenomics of extinct and endangered Hawaiian endemic mints (Lamiaceae)

The Hawaiian mints (Lamiaceae), one of the largest endemic plant lineages in the archipelago, provide an excellent system to study rapid diversification of a lineage with a remote, likely paleohybrid origin. Since their divergence from New World mints 4–5 million years ago the members of this lineage have diversified greatly and represent a remarkable array of vegetative and reproductive phenotypes. Today many members of this group are endangered or already extinct, and molecular phylogenetic work relies largely on herbarium samples collected during the last century. So far a gene-by-gene approach has been utilized, but the recent radiation of the Hawaiian mints has resulted in minimal sequence divergence and hence poor phylogenetic resolution. In our quest to trace the reticulate evolutionary history of the lineage, a resolved maternal phylogeny is necessary. We applied a high-throughput approach to sequence 12 complete or nearly complete plastid genomes from multiple Hawaiian mint species and relatives, including extinct and rare taxa. We also targeted 108 hypervariable regions from throughout the chloroplast genomes in nearly all of the remaining Hawaiian species, and relatives, using a next-generation amplicon sequencing approach. This procedure generated ∼20 Kb of sequence data for each taxon and considerably increased the total number of variable sites over previous analyses. Our results demonstrate the potential of high-throughput sequencing of historic material for evolutionary studies in rapidly evolving lineages. Our study, however, also highlights the challenges of resolving relationships within recent radiations even at the genomic level

Data characterizing the chloroplast genomes of extinct and endangered Hawaiian endemic mints (Lamiaceae) and their close relatives

These data are presented in support of a plastid phylogenomic analysis of the recent radiation of the Hawaiian endemic mints (Lamiaceae), and their close relatives in the genus Stachys, “The quest to resolve recent radiations: Plastid phylogenomics of extinct and endangered Hawaiian endemic mints (Lamiaceae)” [1]. Here we describe the chloroplast genome sequences for 12 mint taxa. Data presented include summaries of gene content and length for these taxa, structural comparison of the mint chloroplast genomes with published sequences from other species in the order Lamiales, and comparisons of variability among three Hawaiian taxa vs. three outgroup taxa. Finally, we provide a list of 108 primer pairs targeting the most variable regions within this group and designed specifically for amplification of DNA extracted from degraded herbarium material