4,047 research outputs found
Teleportation using coupled oscillator states
We analyse the fidelity of teleportation protocols, as a function of resource
entanglement, for three kinds of two mode oscillator states: states with fixed
total photon number, number states entangled at a beam splitter, and the
two-mode squeezed vacuum state. We define corresponding teleportation protocols
for each case including phase noise to model degraded entanglement of each
resource.Comment: 21 pages REVTeX, manuscript format, 7 figures postscript, many
changes to pape
Design Theory and the Australian Tula Adze
The tula adze is a distinctive composite tool that was used in the Australian arid zone during the late Holocene. In this paper we use design theory to investigate why this particular tool form was so pervasive across time and space. Design theory provides a rational means for classifying tool designs and for determining why particular tool design classes were employed over others. We draw upon ethnographic and archaeological evidence to characterize the design of the tula adze and conclude that it is consistently the product of a “reliable” design strategy. We further determine that the high cost of a reliable design was chosen because the tula adze was employed in situations where failure could not be tolerated. Specifically, we argue that an important role of the tula adze was to manufacture wooden goods for not only personal use but more significantly for trade. The quantity and quality of these goods had an extremely strong bearing on the economic sustainability of arid zone Aboriginal groups
Portfolio efficiency and discount factor bounds with conditional information:An Empirical Study
Using ultra-thin parylene films as an organic gate insulator in nanowire field-effect transistors
We report the development of nanowire field-effect transistors featuring an
ultra-thin parylene film as a polymer gate insulator. The room temperature,
gas-phase deposition of parylene is an attractive alternative to oxide
insulators prepared at high temperatures using atomic layer deposition. We
discuss our custom-built parylene deposition system, which is designed for
reliable and controlled deposition of <100 nm thick parylene films on III-V
nanowires standing vertically on a growth substrate or horizontally on a device
substrate. The former case gives conformally-coated nanowires, which we used to
produce functional -gate and gate-all-around structures. These give
sub-threshold swings as low as 140 mV/dec and on/off ratios exceeding at
room temperature. For the gate-all-around structure, we developed a novel
fabrication strategy that overcomes some of the limitations with previous
lateral wrap-gate nanowire transistors. Finally, we show that parylene can be
deposited over chemically-treated nanowire surfaces; a feature generally not
possible with oxides produced by atomic layer deposition due to the surface
`self-cleaning' effect. Our results highlight the potential for parylene as an
alternative ultra-thin insulator in nanoscale electronic devices more broadly,
with potential applications extending into nanobioelectronics due to parylene's
well-established biocompatible properties
Maximal entanglement of squeezed vacuum states via swapping with number-phase measurement
We propose a method to refine entanglement via swapping from a pair of
squeezed vacuum states by performing the Bell measurement of number sum and
phase difference. The resultant states are maximally entangled by adjusting the
two squeezing parameters to the same value. We then describe the teleportation
of number states by using the entangled states prepared in this way.Comment: 4 pages, 1 PS figure, RevTe
Conditional quantum-state transformation at a beam splitter
Using conditional measurement on a beam splitter, we study the transformation
of the quantum state of the signal mode within the concept of two-port
non-unitary transformation. Allowing for arbitrary quantum states of both the
input reference mode and the output reference mode on which the measurement is
performed, we show that the non-unitary transformation operator can be given as
an -ordered operator product, where the value of is entirely determined
by the absolute value of the beam splitter reflectance (or transmittance). The
formalism generalizes previously obtained results that can be recovered by
simple specification of the non-unitary transformation operator. As an
application, we consider the generation of Schr\"odinger-cat-like states. An
extension to mixed states and imperfect detection is outlined.Comment: 7 Postscript figures, using Late
Macroscopically distinct quantum superposition states as a bosonic code for amplitude damping
We show how macroscopically distinct quantum superposition states
(Schroedinger cat states) may be used as logical qubit encodings for the
correction of spontaneous emission errors. Spontaneous emission causes a bit
flip error which is easily corrected by a standard error correction circuit.
The method works arbitrarily well as the distance between the amplitudes of the
superposed coherent states increases.Comment: 4 pages, 2 postscript figures, LaTeX2e, RevTeX, minor changes, 1
reference adde
Pricing Options in Incomplete Equity Markets via the Instantaneous Sharpe Ratio
We use a continuous version of the standard deviation premium principle for
pricing in incomplete equity markets by assuming that the investor issuing an
unhedgeable derivative security requires compensation for this risk in the form
of a pre-specified instantaneous Sharpe ratio. First, we apply our method to
price options on non-traded assets for which there is a traded asset that is
correlated to the non-traded asset. Our main contribution to this particular
problem is to show that our seller/buyer prices are the upper/lower good deal
bounds of Cochrane and Sa\'{a}-Requejo (2000) and of Bj\"{o}rk and Slinko
(2006) and to determine the analytical properties of these prices. Second, we
apply our method to price options in the presence of stochastic volatility. Our
main contribution to this problem is to show that the instantaneous Sharpe
ratio, an integral ingredient in our methodology, is the negative of the market
price of volatility risk, as defined in Fouque, Papanicolaou, and Sircar
(2000).Comment: Keywords: Pricing derivative securities, incomplete markets, Sharpe
ratio, correlated assets, stochastic volatility, non-linear partial
differential equations, good deal bound
Selective Hybridization of a Terpyridine-Based Molecule with a Noble Metal
The electronic properties of metal-molecule interfaces can in principle be
controlled by molecular design and self-assembly, yielding great potential for
future nano- and optoelectronic technologies. However, the coupling between
molecular orbitals and the electronic states of the surface can significantly
influence molecular states. In particular, molecules designed to create
metal-organic self-assembled networks have functional groups that by necessity
are designed to interact strongly with metals. Here, we investigate the
adsorption interactions of a terpyridine (tpy)-based molecule on a noble metal,
Ag(111), by low-temperature scanning tunneling microscopy (STM) and
spectroscopy (STS) together with density functional theory (DFT) calculations.
By comparing the local density of states (DOS) information gained from STS for
the molecule on the bare Ag(111) surface with that of the molecule decoupled
from the underlying metal by a NaCl bilayer, we find that tpy-localized
orbitals hybridize strongly with the metal substrate. Meanwhile, those related
to the phenyl rings that link the two terminal tpy groups are less influenced
by the interaction with the surface. The selective hybridization of the tpy
groups provides an example of strong, orbital-specific electronic coupling
between a functional group and a noble-metal surface, which may alter the
intended balance of interactions and resulting electronic behavior of the
molecule-metal interface
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