3,161 research outputs found
Elastomeric silazane polymers and process for preparing the same Patent
Preparation of elastomeric diamine silazane polymer
Substituted silane-diol polymers have improved thermal stability
Organosilicon polymers were synthesized to produce improved physical and chemical properties, including high thermal stability. Of the polymers produced, poly/4, 4 prime-bisoxybi- phenylene/diphenylsilane, formed from bis/anilino/diphenylsilane and p, p prime-biphenol, was found to have the most desirable properties
Implications of Qudit Superselection rules for the Theory of Decoherence-free Subsystems
The use of d-state systems, or qudits, in quantum information processing is
discussed. Three-state and higher dimensional quantum systems are known to have
very different properties from two-state systems, i.e., qubits. In particular
there exist qudit states which are not equivalent under local unitary
transformations unless a selection rule is violated. This observation is shown
to be an important factor in the theory of decoherence-free, or noiseless,
subsystems. Experimentally observable consequences and methods for
distinguishing these states are also provided, including the explicit
construction of new decoherence-free or noiseless subsystems from qutrits.
Implications for simulating quantum systems with quantum systems are also
discussed.Comment: 13 pages, 1 figures, Version 2: Typos corrected, references fixed and
new ones added, also includes referees suggested changes and a new exampl
Bistability in sine-Gordon: the ideal switch
The sine-Gordon equation, used as the representative nonlinear wave equation,
presents a bistable behavior resulting from nonlinearity and generating
hysteresis properties. We show that the process can be understood in a
comprehensive analytical formulation and that it is a generic property of
nonlinear systems possessing a natural band gap. The approach allows to
discover that sine-Gordon can work as an it ideal switch by reaching a
transmissive regime with vanishing driving amplitude.Comment: Phys. Rev. E, (to be published, May 2005
Overview of Quantum Error Prevention and Leakage Elimination
Quantum error prevention strategies will be required to produce a scalable
quantum computing device and are of central importance in this regard. Progress
in this area has been quite rapid in the past few years. In order to provide an
overview of the achievements in this area, we discuss the three major classes
of error prevention strategies, the abilities of these methods and the
shortcomings. We then discuss the combinations of these strategies which have
recently been proposed in the literature. Finally we present recent results in
reducing errors on encoded subspaces using decoupling controls. We show how to
generally remove mixing of an encoded subspace with external states (termed
leakage errors) using decoupling controls. Such controls are known as ``leakage
elimination operations'' or ``LEOs.''Comment: 8 pages, no figures, submitted to the proceedings of the Physics of
Quantum Electronics, 200
Gas-Rich Companions of Isolated Galaxies
We have used the VLA to search for gaseous remnants of the galaxy formation
process around six extremely isolated galaxies. We found two distinct HI clouds
around each of two galaxies in our sample (UGC 9762 & UGC 11124). These clouds
are rotating and appear to have optical counterparts, strongly implying that
they are typical dwarf galaxies. The companions are currently weakly
interacting with the primary galaxy, but have short dynamical friction
timescales (~1 Gyr) suggesting that these triple galaxy systems will shortly
collapse into one massive galaxy. Given that the companions are consistent with
being in circular rotation about the primary galaxy, and that they have small
relative masses, the resulting merger will be a minor one. The companions do,
however, contain enough gas that the merger will represent a significant
infusion of fuel to drive future star formation, bar formation, or central
activity, while building up the mass of the disk thus making these systems
important pieces of the galaxy formation and evolution process.Comment: Corrected dynamical friction calculation error. Revised discussion &
conclusions. 7 pages, 4 tables, 6 figures, to appear in May 1999 Astronomical
Journa
Bistable light detectors with nonlinear waveguide arrays
Bistability induced by nonlinear Kerr effect in arrays of coupled waveguides
is studied and shown to be a means to conceive light detectors that switch
under excitation by a weak signal. The detector is obtained by coupling two
single 1D waveguide to an array of coupled waveguides with adjusted indices and
coupling. The process is understood by analytical description in the
conservative and continuous case and illustrated by numerical simulations of
the model with attenuation.Comment: Phys. Rev. Lett., v.94, (2005, to be published
Miniature Optical Atomic Clock: Stabilization of a Kerr Comb Oscillator
Mechanical clocks consist of a pendulum and a clockwork that translates the
pendulum period to displayed time. The most advanced clocks utilize optical
transitions in atoms in place of the pendulum and an optical frequency comb
generated by a femtosecond laser as the clockwork. The comb must be stabilized
at two points along its frequency spectrum: one with a laser to lock a comb
line to a transition in the atom, and another through self referencing to
stabilize the frequency interval between the comb lines. This approach requires
advanced techniques, so optical atomic clocks are currently laboratory devices
in specialized labs. In this paper we leverage unique properties of Kerr comb
oscillators for realization of optical atomic clocks in miniature form factors.
In particular, we describe a clock based on D1 transition of 87Rb that fits in
the palm of the hand, and can be further miniaturized to chip scale.Comment: 4 pages, 4 figure
Topological structures of adiabatic phase for multi-level quantum systems
The topological properties of adiabatic gauge fields for multi-level
(three-level in particular) quantum systems are studied in detail. Similar to
the result that the adiabatic gauge field for SU(2) systems (e.g. two-level
quantum system or angular momentum systems, etc) have a monopole structure, the
curvature two-forms of the adiabatic holonomies for SU(3) three-level and SU(3)
eight-level quantum systems are shown to have monopole-like (for all levels) or
instanton-like (for the degenerate levels) structures.Comment: 15 pages, no figures. Accepted by J.Phys.
- …