2,463 research outputs found
Invisibly decaying Higgs boson in the Littlest Higgs model with T-parity
We show that there are regions in the parameter space of the Littlest Higgs
model with T-parity, allowed by electroweak precision data, where the Higgs
boson can decay invisibly into a pair of heavy photons A_H with a substantial
branching ratio. For a symmetry breaking scale f in the range 450-600 GeV, the
BR(H -> A_H A_H) can be up to 95% for an intermediate mass Higgs, and from 20%
down to a few percents for a Higgs boson of mass 200 GeV or above. The total
decay width of the Higgs boson can thereby be enhanced by an order of magnitude
compared to the Standard Model for Higgs masses around 130 GeV.Comment: 4 pages, 2 figures, Latex (stylefiles included); Talk presented by
A.N. at the International Workshop on Theoretical High Energy Physics (IWTHEP
2007), Roorkee, India, 15-20 March 2007, to appear in the proceeding
Non-destructive Orthonormal State Discrimination
We provide explicit quantum circuits for the non-destructive deterministic
discrimination of Bell states in the Hilbert space , where is
qudit dimension. We discuss a method for generalizing this to non-destructive
measurements on any set of orthogonal states distributed among parties.
From the practical viewpoint, we show that such non-destructive measurements
can help lower quantum communication complexity under certain conditions.Comment: 11 pages, 6 fugure
Bilarge neutrino mixing in R-parity violating supersymmetry: the role of right-chiral neutrino superfields
We consider the possibility of neutrino mass generation in a supersymmetric
model where lepton number can be violated by odd units. The different patterns
of mixing in the quark and lepton sectors are attributed to the persence of
right-chiral neutrino superfields which (a) enter into Yukawa couplings via
non-renormalizable interaction with hidden sector fields, and (b) can violate
lepton number by odd units. Both of these features are shown to be the result
of some global quantum number which is violated when SUSY is broken in the
hidden sector. It is shown how such a scenario, together with all known
R-parity violating effects, can lead to neutrino masses and bilarge mixing via
seesaw as well as radiative mechanisms. Some sample values of the various
parameters involved, consistent with electroweak symmetry breaking constraints,
are presented as illustrations.Comment: 19 pages. Minor modificaitons are made in the text. This version is
to appear in Physical Review
Observation of coherent Josephson response in the non-linear ab-plane microwave impedance of single crystals
We report novel non-linear phenomena in the -plane microwave impedance of
single crystals. The vs. data are well
described by the non-linear RSJ model : . The entire crystal behaves like a single Josephson junction. The
extraordinary coherence of the data suggests an intrinsic mechanism.Comment: 2 pages,1 figure, Submitted to Proc. of M^2SHTSC-V (Beijing), also
available at http://sagar.physics.neu.edu/preprint
High fidelity single-shot readout of a transmon qubit using a SLUG {\mu}wave amplifier
We report high-fidelity, quantum nondemolition, single-shot readout of a
superconducting transmon qubit using a DC-biased superconducting low-inductance
undulatory galvanometer(SLUG) amplifier. The SLUG improves the system
signal-to-noise ratio by 7 dB in a 20 MHz window compared with a bare HEMT
amplifier. An optimal cavity drive pulse is chosen using a genetic search
algorithm, leading to a maximum combined readout and preparation fidelity of
91.9% with a measurement time of Tmeas = 200ns. Using post-selection to remove
preparation errors caused by heating, we realize a combined preparation and
readout fidelity of 94.3%.Comment: 4 pages and 3 figure
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