317 research outputs found

    Canted ground state in artificial molecules at high magnetic fields

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    We analyze the transitions that a magnetic field provokes in the ground state of an artificial homonuclear diatomic molecule. For that purpose, we have performed numerical diagonalizations for a double quantum dot around the regime of filling factor 2. We present phase diagrams in terms of tunneling and Zeeman couplings, and confinement strength. We identify a series of transitions from ferromagnetic to symmetric states through a set of canted states with antiferromagnetic couping between the two quantum dots

    Entangled state preparation via dissipation-assisted adiabatic passages

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    The main obstacle for coherent control of open quantum systems is decoherence due to different dissipation channels and the inability to precisely control experimental parameters. To overcome these problems we propose to use dissipation-assisted adiabatic passages. These are relatively fast processes where the presence of spontaneous decay rates corrects for errors due to non-adiabaticity while the system remains in a decoherence-free state and behaves as predicted for an adiabatic passage. As a concrete example we present a scheme to entangle atoms by moving them in and out of an optical cavity.Comment: 11 pages, 7 figures, minor changes, accepted for publication in Phys. Rev.

    Measurement of branching fraction ratios and CP asymmetries in B±DCPK±B^{\pm} \to D_{CP}K^{\pm}

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    We report results on the decay BDCPKB^{-} \to D_{CP}K^{-} and its charge conjugate using a data sample of 85.4 million BBˉB\bar{B} pairs recorded at the Υ(4S)\Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric e+ee^{+}e^{-} storage ring. Ratios of branching fractions of Cabibbo-suppressed to Cabibbo-favored processes are determined to be B(BD0K)/B(BD0π)=0.077±0.005(stat)±0.006(sys){\cal B}(B^- \to D^0 K^-)/{\cal B}(B^- \to D^0 \pi^-)= 0.077 \pm 0.005(stat) \pm 0.006(sys), B(BD1K)/B(BD1π)=0.093±0.018(stat)±0.008(sys){\cal B}(B^- \to D_1 K^-)/{\cal B}(B^- \to D_1 \pi^-) = 0.093 \pm 0.018(stat) \pm 0.008(sys) and B(BD2K)/B(BD2π)=0.108±0.019(stat)±0.007(sys){\cal B}(B^- \to D_2 K^-)/{\cal B}(B^- \to D_2 \pi^-) = 0.108 \pm 0.019(stat) \pm 0.007(sys) where the indices 1 and 2 represent the CP=+1 and CP=-1 eigenstates of the D0D0ˉD^{0}-\bar{D^{0}} system, respectively. We find the partial-rate charge asymmetries for BDCPKB^{-} \to D_{CP}K^{-} to be A1=0.06±0.19(stat)±0.04(sys){\cal{A}}_1 = 0.06 \pm 0.19(stat) \pm 0.04(sys) and A2=0.19±0.17(stat)±0.05(sys){\cal{A}}_2 = -0.19 \pm 0.17(stat) \pm 0.05(sys).Comment: 10 pages, 3 figures, submitted to Physical Review

    Study of the B^0 Semileptonic Decay Spectrum at the Upsilon(4S) Resonance

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    We have made a first measurement of the lepton momentum spectrum in a sample of events enriched in neutral B's through a partial reconstruction of B0 --> D*- l+ nu. This spectrum, measured with 2.38 fb**-1 of data collected at the Upsilon(4S) resonance by the CLEO II detector, is compared directly to the inclusive lepton spectrum from all Upsilon(4S) events in the same data set. These two spectra are consistent with having the same shape above 1.5 GeV/c. From the two spectra and two other CLEO measurements, we obtain the B0 and B+ semileptonic branching fractions, b0 and b+, their ratio, and the production ratio f+-/f00 of B+ and B0 pairs at the Upsilon(4S). We report b+/b0=0.950 (+0.117-0.080) +- 0.091, b0 = (10.78 +- 0.60 +- 0.69)%, and b+ = (10.25 +- 0.57 +- 0.65)%. b+/b0 is equivalent to the ratio of charged to neutral B lifetimes, tau+/tau0.Comment: 14 page, postscript file also available at http://w4.lns.cornell.edu/public/CLN

    Measurement of the Mass Splittings between the bbˉχb,J(1P)b\bar{b}\chi_{b,J}(1P) States

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    We present new measurements of photon energies and branching fractions for the radiative transitions: Upsilon(2S)->gamma+chi_b(J=0,1,2). The masses of the chi_b states are determined from the measured radiative photon energies. The ratio of mass splittings between the chi_b substates, r==(M[J=2]-M[J=1])/(M[J=1]-M[J=0]) with M the chi_b mass, provides information on the nature of the bbbar confining potential. We find r(1P)=0.54+/-0.02+/-0.02. This value is in conflict with the previous world average, but more consistent with the theoretical expectation that r(1P)<r(2P); i.e., that this mass splittings ratio is smaller for the chi_b(1P) triplet than for the chi_b(2P) triplet.Comment: 11 page postscript file, postscript file also available through http://w4.lns.cornell.edu/public/CLN

    Radiative Decay Modes of the D0D^{0} Meson

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    Using data recorded by the CLEO-II detector at CESR we have searched for four radiative decay modes of the D0D^0 meson: D0ϕγD^0\to\phi\gamma, D0ωγD^0\to\omega\gamma, D0KˉγD^0\to\bar{K}^{*}\gamma, and D0ρ0γD^0\to\rho^0\gamma. We obtain 90% CL upper limits on the branching ratios of these modes of 1.9×1041.9\times 10^{-4}, 2.4×1042.4\times 10^{-4}, 7.6×1047.6\times 10^{-4} and 2.4×1042.4\times 10^{-4} respectively.Comment: 15 page postscript file, postscript file also available through http://w4.lns.cornell.edu/public/CLN

    Effects of marital/dependency status on reenlistment behavior of second-term enlisted females.

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    This thesis investigates the relationship of reenlistment decisions of second-term enlisted women in the military to their marital and dependent status, using individual-level data from the 1985 DoD Survey of Officer and Enlisted Personnel. Actual reenlistment status (December 1988) of each survey respondent was merged with the data set. Logit analysis was used to estimate the likelihood of a respondent choosing to reenlist given her set of individual characteristics. Separate logit models were estimated for the following groups of second-term personnel: single women without children, single women with children, married women without children, and married women with children. Certain variables affected all groups similarly (pay grade, minority status, perception of civilian job alternatives). Others exerted differential impact on subgroups (job satisfaction, traditionality of job). Results illustrated differential reenlistment behavior based upon the presence of children. Results may be used to target reenlistment incentives for specified marital/dependent status groups.http://archive.org/details/effectsofmarital00edwaLieutenant, United States NavyApproved for public release; distribution is unlimited

    Rare SLC13A1 variants associate with intervertebral disc disorder highlighting role of sulfate in disc pathology

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    Publisher Copyright: © 2022, The Author(s).Back pain is a common and debilitating disorder with largely unknown underlying biology. Here we report a genome-wide association study of back pain using diagnoses assigned in clinical practice; dorsalgia (119,100 cases, 909,847 controls) and intervertebral disc disorder (IDD) (58,854 cases, 922,958 controls). We identify 41 variants at 33 loci. The most significant association (ORIDD = 0.92, P = 1.6 × 10−39; ORdorsalgia = 0.92, P = 7.2 × 10−15) is with a 3’UTR variant (rs1871452-T) in CHST3, encoding a sulfotransferase enzyme expressed in intervertebral discs. The largest effects on IDD are conferred by rare (MAF = 0.07 − 0.32%) loss-of-function (LoF) variants in SLC13A1, encoding a sodium-sulfate co-transporter (LoF burden OR = 1.44, P = 3.1 × 10−11); variants that also associate with reduced serum sulfate. Genes implicated by this study are involved in cartilage and bone biology, as well as neurological and inflammatory processes.Peer reviewe
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