On-demand microwave generator of shaped single photons

We demonstrate the full functionality of a circuit that generates single microwave photons on demand, with a wave packet that can be modulated with a near-arbitrary shape. We achieve such a high tunability by coupling a superconducting qubit near the end of a semi-infinite transmission line. A dc superconducting quantum interference device shunts the line to ground and is employed to modify the spatial dependence of the electromagnetic mode structure in the transmission line. This control allows us to couple and decouple the qubit from the line, shaping its emission rate on fast time scales. Our decoupling scheme is applicable to all types of superconducting qubits and other solid-state systems and can be generalized to multiple qubits as well as to resonators.Comment: 10 pages, 7 figures. Published versio

Application of Nimbus-6 microwave data to problems in precipitation prediction for the Pacific west coast

The preliminary results of a research study that emphasizes the analysis and interpretation of data related to total precipitable water and nonprecipitating cloud liquid water obtained from NIMBUS-6 SCAMS are reported. Sixteen cyclonic storm situations in the northeastern Pacific Ocean that resulted in significant rainfall along the west coast of the United States during the winter season October 1975 through February 1976 are analyzed in terms of their distributions and amounts of total water vapor and liquid water, as obtained from SCAMS data. The water-substance analyses for each storm case are related to the distribution and amount of coastal precipitation observed during the subsequent time period when the storm system crosses the coastline. Concomitant precipitation predictions from the LFM are also incorporated. Techniques by which satellite microwave data over the ocean can be used to improve precipitation prediction for the Pacific West Coast are emphasized

Microscopic origin of the next generation fractional quantum Hall effect

Most of the fractions observed to date belong to the sequences $\nu=n/(2pn\pm 1)$ and $\nu=1-n/(2pn\pm 1)$, $n$ and $p$ integers, understood as the familiar {\em integral} quantum Hall effect of composite fermions. These sequences fail to accommodate, however, many fractions such as $\nu=4/11$ and 5/13, discovered recently in ultra-high mobility samples at very low temperatures. We show that these "next generation" fractional quantum Hall states are accurately described as the {\em fractional} quantum Hall effect of composite fermions

Thermal expansion mismatch and oxidation in thermal barrier coatings

Thermal barrier coatings (TBC) for advanced gas turbine blades have been under intensive development during the last several years. This investigation is intended to achieve a clearer understanding of the mechanical behavior of plasma sprayed zirconia-yttria TBCs, involving a nickle-chromium-aluminum bond coat. The near term objectives are to study the stress states in a relatively simple model TBC subjected to steady state thermal loading. The resulting thermal expansion mismatch and oxidation have been primary targets for the study. The finite element approach and the effects of thermal mismatch and oxidation are described. A proposed mechanism for oxidation induced coating failure is also presented

Quantum oscillations observed in graphene at microwave frequencies

We have measured the microwave conductance of mechanically exfoliated graphene at frequencies up to 8.5 GHz. The conductance at 4.2 K exhibits quantum oscillations, and is independent of the frequency

The magnetic dipole transitions in the (cbˉ)(c\bar{b}) binding system

The magnetic dipole transitions between the vector mesons $B_c^*$ and their relevant pseudoscalar mesons $B_c$ ($B_c$, $B_c^*$, $B_c(2S)$, $B_c^*(2S)$, $B_c(3S)$ and $B_c^*(3S)$ etc, the binding states of $(c\bar{b})$ system) of the $B_c$ family are interesting. To see the `hyperfine' splitting due to spin-spin interaction is an important topic for understanding the spin-spin interaction and the spectrum of the the $(c\bar{b})$ binding system. The knowledge about the magnetic dipole transitions is also very useful for identifying the vector boson $B_c^*$ mesons experimentally, whose masses are just slightly above the masses of their relevant pseudoscalar mesons $B_c$ accordingly. Considering the possibility to observe the vector mesons via the transitions at $Z^0$ factory and the potentially usages of the theoretical estimate on the transitions, we fucus our efforts on calculating the magnetic dipole transitions, i.e. precisely to calculate the rates for the transitions such as decays $B_c^*\to B_c\gamma$ and $B_c^*\to B_c e^+e^-$, and particularly work in the Behte-Salpeter framework. In the estimate, as a typical example, we carefully investigate the dependance of the rate $\Gamma(B_c^*\to B_c\gamma)$ on the mass difference $\Delta M=M_{B_c^*}-M_{B_c}$ as well.Comment: 10 pages, 2 figures, 1 tabl

Magnetic Hydrogen Atmosphere Models and the Neutron Star RX J1856.5-3754

RX J1856.5-3754 is one of the brightest nearby isolated neutron stars, and considerable observational resources have been devoted to it. However, current models are unable to satisfactorily explain the data. We show that our latest models of a thin, magnetic, partially ionized hydrogen atmosphere on top of a condensed surface can fit the entire spectrum, from X-rays to optical, of RX J1856.5-3754, within the uncertainties. In our simplest model, the best-fit parameters are an interstellar column density N_H \approx 1x10^20 cm^-2 and an emitting area with R^infty \approx 17 km (assuming a distance to RX J1856.5-3754 of 140 pc), temperature T^infty \approx 4.3x10^5 K, gravitational redshift z_g \sim 0.22, atmospheric hydrogen column y_H \approx 1 g cm^-2, and magnetic field B \approx (3-4)x10^12 G; the values for the temperature and magnetic field indicate an effective average over the surface. We also calculate a more realistic model, which accounts for magnetic field and temperature variations over the neutron star surface as well as general relativistic effects, to determine pulsations; we find there exist viewing geometries that produce pulsations near the currently observed limits. The origin of the thin atmospheres required to fit the data is an important question, and we briefly discuss mechanisms for producing these atmospheres. Our model thus represents the most self-consistent picture to date for explaining all the observations of RX J1856.5-3754.Comment: 11 pages, 8 figures; MNRAS, accepte

Complementarity of Semileptonic BB to K2∗(1430)K_2^*(1430) and K∗(892)K^*(892) Decays in the Standard Model with Fourth Generation

The $B\rightarrow K_{2}^{\ast}(1430)l^{+}l^{-}$ $(l=\mu,\tau)$ decays are analyzed in the Standard Model extended to fourth generation of quarks (SM4). The decay rate, forward-backward asymmetry, lepton polarization asymmetries and the helicity fractions of the final state $K^{*}_{2}(1430)$ meson are obtained using the form factors calculated in the light cone sum rules (LCSR) approach. We have utilized the constraints on different fourth generation parameters obtained from the experimental information on $K$, $B$ and $D$ decays and from the electroweak precision data to explore their impact on the $B\rightarrow K_{2}^{\ast}(1430)l^{+}l^{-}$ decay. We find that the values of above mentioned physical observables deviate deviate significantly from their minimal SM predications. We also identify a number of correlations between various observables in $B\rightarrow K_{2}^{\ast}(1430)l^{+}l^{-}$ and $B\rightarrow K^{\ast}(892)l^{+}l^{-}$ decays. Therefore a combined analysis of these two decays will compliment each other in the searches of SM4 effects in flavor physics.Comment: 28 pages, 12 figure