1,822 research outputs found
Coupling of Josephson current qubits using a connecting loop
We propose a coupling scheme for the three-Josephson junction qubits which
uses a connecting loop, but not mutual inductance. Present scheme offers the
advantages of a large and tunable level splitting in implementing the
controlled-NOT (CNOT) operation. We calculate the switching probabilities of
the coupled qubits in the CNOT operations and demonstrate that present CNOT
gate can meet the criteria for the fault-tolerant quantum computing. We obtain
the coupling strength as a function of the coupling energy of the Josephson
junction and the length of the connecting loop which varies with selecting two
qubits from the scalable design.Comment: 5 pages with updates, version to appear in Phys. Rev.
Comments on "Vortex Glass and Lattice Melting Transitions in a YNi_2B_2C Single Crystal"
Recently, Mun et.al. (Phys. Rev. Lett., 76, 2790 (1996)) have published their
results on single crystal YNi_2B_2C, claiming that their experimental
observations can be explained in terms of formation of Vortex Glass and Lattice
melting. Our experiments, carried out on samples obtained from the SAME source,
reveal a much richer phase diagram and span wider regions of experimental
parameter space than Mun et. al. that encompasses most of their observations.
We speculate that this material has anomalous intrinsic properties and the
results cannot be explained by simple models about the flux lattice.Comment: 1 page, LaTeX type, 1 PostScript figure, Uses PRABIB.STY file, 600
dpi PS file available at http://sagar.physics.neu.edu/preprints.html To
appear in Physical Review Letter
Rites of Passage: Debutante Balls in Filipino-American Culture
The debutante ball is a traditional Western ritual often designed to celebrate young women’s transition from childhood to adulthood. The word debut (i.e., to enter into society) comes from French language but came into use by the English during the reign of King George the 3rd (1760- 1820). From 1837 on, the young women were referred to as debutantes later shortened to debs (Haynes, 2005)
Reverse Doppler Effect of Sound
We report observation of reverse Doppler effect in a double negative acoustic
metamaterial. The metamaterial exhibited negative phase velocity and positive
group velocity. The dispersion relation is such that the wavelength
corresponding to higher frequency is longer. We observed that the frequency was
down-shifted for the approaching source, and up-shifted when the source
receded
Thermoelectric power of Ba(Fe1-xRux)2As2 and Ba(Fe1-xCox)2As2: possible changes of Fermi surface with and without changes in electron count
Temperature-dependent, in-plane, thermoelectric power (TEP) data are
presented for Ba(Fe1-xRux)2As2 (0 < x < 0.36) single crystals. The previously
outlined x - T phase diagram for this system is confirmed. The analysis of TEP
evolution with Ru-doping suggests significant changes in the electronic
structure, correlations and/or scattering occurring near ~7% and ~30% of
Ru-doping levels. These results are compared with an extended set of TEP data
for the electron-doped Ba(Fe1-xCox)2As2 series
Superconductivity from purely repulsive interactions in the strong coupling approach : Application of the SU(2) slave-rotor theory to the Hubbard model
We propose a mechanism of superconductivity from purely repulsive
interactions in the strong coupling regime, where the BCS
(Bardeen-Cooper-Schrieffer) mechanism such as the spin-fluctuation approach is
difficult to apply. Based on the SU(2) slave-rotor representation of the
Hubbard model, we find that the single energy scale for the amplitude formation
of Cooper pairs and their phase coherence is separated into two energy scales,
allowing the so called pseudogap state where such Cooper pairs are coherent
locally but not globally, interpreted as realization of the density-phase
uncertainty principle. This superconducting state shows the temperature-linear
decreasing ratio of superfluid weight, resulting from strong phase
fluctuations
Impact of irreversibility and uncertainty on the timing of infrastructure projects
This paper argues that because of the irreversibility and uncertainty associated with Build - Operate - Transfer (BOT) infrastructure projects, their financial evaluation should also routinely include the determination of the value of the option to defer the construction start-up. This ensures that project viability is comprehensively assessed before any revenue or loan guarantees are considered by project sponsors to support the project. This paper shows that the framework can be used even in the context of the intuitive binomial lattice model. This requires estimating volatility directly from the evolution of the net operating income while accounting for the correlation between the revenue and costs functions. This approach ensures that the uncertainties usually associated with toll revenues, in particular, are thoroughly investigated and their impact on project viability is thoroughly assessed. This paper illustrates the usefulness of the framework with data from an actual (BOT) toll road project. The results show that by postponing the project for a couple of years the project turns out to be viable, whereas it was not without the deferral. The evaluation approach proposed therefore provides a better framework for determining when and the extent of government financial support, if any, that may be needed to support a BOT project on the basis of project economics. The analysis may also be applicable to private sector investment projects, which are characterized by irreversibility and a high rate of uncertainty
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