Modulational instability criteria for two-component Bose-Einstein condensates

The stability of colliding Bose-Einstein condensates is investigated. A set of coupled Gross-Pitaevskii equations is thus considered, and analyzed via a perturbative approach. No assumption is made on the signs (or magnitudes) of the relevant parameters like the scattering lengths and the coupling coefficients. The formalism is therefore valid for asymmetric as well as symmetric coupled condensate wave states. A new set of explicit criteria is derived and analyzed. An extended instability region, in addition to an enhanced instability growth rate is predicted for unstable two component bosons, as compared to the individual (uncoupled) state.Comment: 4 pages, 1 figur

Scalable Ion Trap Quantum Computing without Moving Ions

A hybrid quantum computing scheme is studied where the hybrid qubit is made of an ion trap qubit serving as the information storage and a solid-state charge qubit serving as the quantum processor, connected by a superconducting cavity. In this paper, we extend our previous work [1] and study the decoherence, coupling and scalability of the hybrid system. We present our calculations of the decoherence of the coupled ion - charge system due to the charge fluctuations in the solid-state system and the dissipation of the superconducting cavity under laser radiation. A gate scheme that exploits rapid state flips of the charge qubit to reduce decoherence by the charge noise is designed. We also study a superconducting switch that is inserted between the cavity and the charge qubit and provides tunable coupling between the qubits. The scalability of the hybrid scheme is discussed together with several potential experimental obstacles in realizing this scheme

Department of the Interior. United States Geological Survey. J. W. Powell, Director. Mineral resources of the United States

52-1Mineral Resources of the U.S. [3000] Coal in Indian Territory.1892-3

Precision Measurement of the Proton Flux in Primary Cosmic Rays from Rigidity 1 GV to 1.8 TV with the Alpha Magnetic Spectrometer on the International Space Station

A precise measurement of the proton flux in primary cosmic rays with rigidity (momentum/charge) from 1 GV to 1.8 TV is presented based on 300 million events. Knowledge of the rigidity dependence of the proton flux is important in understanding the origin, acceleration, and propagation of cosmic rays. We present the detailed variation with rigidity of the flux spectral index for the first time. The spectral index progressively hardens at high rigidities.Peer Reviewe

Appropriation for friendly Indians. Letter from the Secretary of the Interior, transmitting a communication from the Acting Commissioner of Indian Affairs, relative to an appropriation for the relief of certain friendly Indians

40-2AppropriationsAppropriations for Friendly Indians. [1345] Kawas, Osages, Apaches, Arapahoes, and Cheyennes; end of hostilities after the council at Medicine Lodge Creek.1868-7

Emergence of superfluid transport in a dynamical system of ultracold atoms

The dynamics of a Bose-Einstein condensate is studied theoretically in a combined periodic plus harmonic external potential. Different dynamical regimes of stable and unstable collective dipole and Bloch oscillations are analysed in terms of a quantum mechanical pendulum model. Nonlinear interactions are shown to counteract quantum-mechanical dephasing and lead to phase-coherent, superfluid transport

Fur-bearing animals in Alaska. Letter from the Secretary of the Treasury, in response to a resolution of the House calling for information in regard to the lease of the right to take fur seals in Alaska.

50-1Merchant Marine and FisheriesFur Bearing Animals in Alaska. [2561] Education of the natives; elimination of liquor traffic.1888-20

Tests of the naturalness of the coupling constants in ChPT at order p^6

We derive constraints on combinations of O(p^6) chiral coupling constants by matching a recent two-loop calculation of the pi-K scattering amplitude with a set of sum rules. We examine the validity of the natural expectation that the values of the chiral couplings can be associated with physics properties of the light resonance sector. We focus, in particular, on flavour symmetry breaking of vector resonances. A resonance chiral Lagrangian is constructed which incorporates flavour symmetry breaking more completely than was done before. We use pi-K unsubtracted sum rules as tests of the modelling of the resonance contributions to the chiral couplings. In some cases the O(p^6) couplings are found not to be dominated by the resonance contributions.Comment: 15 pages, 5 figures; v2: minor improvements, to appear in Eur. Phys. J.

Decays of sigma, kappa, a0(980) and fo(980)

Ratios of coupling constants for these decays are compared with q-qbar predictions and Jaffe's 4-quark model. In both models, the predicted ratio g^2(kappa -> K-pi)/ g^2(sigma -> pi-pi) is much too small. Also, for q-qbar, the predicted ratio g^2(kappa -> K-eta ')/g^2(kappa -> K-pi) is much larger than observed. Both models fail for g^2(fo -> KK)/g^2(a0 -> KK). This ratio requires that fo has a dominant KK component. It arises naturally because the fo pole lies very close to the KK threshold, giving its wave function a long KK tail.Comment: 13 pages, 2 figures, Small addition on systematic error

A new analysis of πK\pi K scattering from Roy and Steiner type equations

With the aim of generating new constraints on the OZI suppressed couplings of chiral perturbation theory a set of six equations of the Roy and Steiner type for the $S$- and $P$-waves of the $\pi K$ scattering amplitudes is derived. The range of validity and the multiplicity of the solutions are discussed. Precise numerical solutions are obtained in the range E\lapprox 1 GeV which make use as input, for the first time, of the most accurate experimental data available at $E > 1$ GeV for both $\pi K\to\pi K$ and $\pi\pi\to K\bar{K}$ amplitudes. Our main result is the determination of a narrow allowed region for the two S-wave scattering lengths. Present experimental data below 1 GeV are found to be in generally poor agreement with our results. A set of threshold expansion parameters, as well as sub-threshold parameters are computed. For the latter, matching with the SU(3) chiral expansion at NLO is performed.Comment: 45 pages, 17 figures. v2: New title, minor correction