11,669 research outputs found
Towards predicting post-editing productivity
Machine translation (MT) quality is generally measured via automatic metrics, producing scores that have no meaning for translators who are required to post-edit MT output or for project managers who have to plan and budget for transla- tion projects. This paper investigates correlations between two such automatic metrics (general text matcher and translation edit rate) and post-editing productivity. For the purposes of this paper, productivity is measured via processing speed and cognitive measures of effort using eye tracking as a tool. Processing speed, average fixation time and count are found to correlate well with the scores for groups of segments. Segments with high GTM and TER scores require substantially less time and cognitive effort than medium or low-scoring segments. Future research involving score thresholds and confidence estimation is suggested
Quantum gate characterization in an extended Hilbert space
We describe an approach for characterizing the process of quantum gates using
quantum process tomography, by first modeling them in an extended Hilbert
space, which includes non-qubit degrees of freedom. To prevent unphysical
processes from being predicted, present quantum process tomography procedures
incorporate mathematical constraints, which make no assumptions as to the
actual physical nature of the system being described. By contrast, the
procedure presented here ensures physicality by placing physical constraints on
the nature of quantum processes. This allows quantum process tomography to be
performed using a smaller experimental data set, and produces parameters with a
direct physical interpretation. The approach is demonstrated by example of
mode-matching in an all-optical controlled-NOT gate. The techniques described
are non-specific and could be applied to other optical circuits or quantum
computing architectures.Comment: 4 pages, 2 figures, REVTeX (published version
Giant optical Faraday rotation induced by a single electron spin in a quantum dot: Applications to entangling remote spins via a single photon
We propose a quantum non-demolition method - giant Faraday rotation - to
detect a single electron spin in a quantum dot inside a microcavity where
negatively-charged exciton strongly couples to the cavity mode. Left- and
right-circularly polarized light reflected from the cavity feels different
phase shifts due to cavity quantum electrodynamics and the optical spin
selection rule. This yields giant and tunable Faraday rotation which can be
easily detected experimentally. Based on this spin-detection technique, a
scalable scheme to create an arbitrary amount of entanglement between two or
more remote spins via a single photon is proposed.Comment: 5 pages, 3 figure
Negotiating Relationally: The Dynamics of the Relational Self In Negotiations
Although negotiation research is thriving, it has been criticized as having an arelational bias—emphasizing autonomy, competition, and rationality over interdependence, cooperation, and relationality. In this article, we advance a new model of relationality in negotiation. Drawing on research in social psychology, we describe the construct of relational self-construals (RSC) and present a temporal model of RSC and negotiation. After delineating the conditions through which RSC becomes accessible in negotiation and conditions that inhibit its use, we discuss how RSC affects negotiators\u27 pre-negotiation psychological states, early and later tactics, and negotiation outcomes. We illustrate a number of distinct relational dynamics that can occur based on the dyadic composition of RSC, each of which brings distinct benefits and costs to the negotiation table. Implications for the science and practice of negotiation are discussed
High-Fidelity Z-Measurement Error Correction of Optical Qubits
We demonstrate a quantum error correction scheme that protects against
accidental measurement, using an encoding where the logical state of a single
qubit is encoded into two physical qubits using a non-deterministic photonic
CNOT gate. For the single qubit input states |0>, |1>, |0>+|1>, |0>-|1>,
|0>+i|1>, and |0>-i|1> our encoder produces the appropriate 2-qubit encoded
state with an average fidelity of 0.88(3) and the single qubit decoded states
have an average fidelity of 0.93(5) with the original state. We are able to
decode the 2-qubit state (up to a bit flip) by performing a measurement on one
of the qubits in the logical basis; we find that the 64 1-qubit decoded states
arising from 16 real and imaginary single qubit superposition inputs have an
average fidelity of 0.96(3).Comment: 4 pages, 4 figures, comments welcom
Strongly enhanced photon collection from diamond defect centres under micro-fabricated integrated solid immersion lenses
The efficiency of collecting photons from optically active defect centres in
bulk diamond is greatly reduced by refraction and reflection at the diamond-air
interface. We report on the fabrication and measurement of a geometrical
solution to the problem; integrated solid immersion lenses (SILs) etched
directly into the surface of diamond. An increase of a factor of 10 was
observed in the saturated count-rate from a single negatively charged
nitrogen-vacancy (NV-) within a 5um diameter SIL compared with NV-s under a
planar surface in the same crystal. A factor of 3 reduction in background
emission was also observed due to the reduced excitation volume with a SIL
present. Such a system is potentially scalable and easily adaptable to other
defect centres in bulk diamond.Comment: 5 Pages, 5 figures (4 subfigures) - corrected typ
Thermal radio emission from novae & symbiotics with the Square Kilometre Array
The thermal radio emission of novae during outburst enables us to derive
fundamental quantities such as the ejected mass, kinetic energy, and density
profile of the ejecta. Recent observations with newly-upgraded facilities such
as the VLA and e-MERLIN are just beginning to reveal the incredibly complex
processes of mass ejection in novae (ejections appear to often proceed in
multiple phases and over prolonged timescales). Symbiotic stars can also
exhibit outbursts, which are sometimes accompanied by the expulsion of material
in jets. However, unlike novae, the long-term thermal radio emission of
symbiotics originates in the wind of the giant secondary star, which is
irradiated by the hot white dwarf. The effect of the white dwarf on the giant's
wind is strongly time variable, and the physical mechanism driving these
variations remains a mystery (possibilities include accretion instabilities and
time-variable nuclear burning on the white dwarf's surface).
The exquisite sensitivity of SKA1 will enable us to survey novae throughout
the Galaxy, unveiling statistically complete populations. With SKA2 it will be
possible to carry out similar studies in the Magellanic Clouds. This will
enable high-quality tests of the theory behind accretion and mass loss from
accreting white dwarfs, with significant implications for determining their
possible role as Type Ia supernova progenitors. Observations with SKA1-MID in
particular, over a broad range of frequencies, but with emphasis on the higher
frequencies, will provide an unparalleled view of the physical processes
driving mass ejection and resulting in the diversity of novae, whilst also
determining the accretion processes and rates in symbiotic stars.Comment: 13 pages, 3 figures, in proceedings of "Advancing Astrophysics with
the Square Kilometre Array", PoS(AASKA14)116, in pres
An All Optical Fibre Quantum Controlled-NOT Gate
We report the first experimental demonstration of an optical controlled-NOT
gate constructed entirely in fibre. We operate the gate using two heralded
optical fibre single photon sources and find an average logical fidelity of 90%
and an average process fidelity of 0.83<F<0.91. On the basis of a simple model
we are able to conclude that imperfections are primarily due to the photon
sources, meaning that the gate itself works with very high fidelity.Comment: 4 pages, 4 figures, comments welcom
Dynamics of the Lyman alpha and C IV emitting gas in 3C 273
In this paper we study the variability properties of the Lyman alpha and C IV
emission lines in 3C273 using archival IUE observations. Our data show for the
first time the existence of variability on time scales of several years. We
study the spatial distribution and the velocity field of the emitting gas by
performing detailed analyses on the line variability using correlations, 1D and
2D response functions, and principal component analysis. In both lines we find
evidence for two components, one which has the dynamic properties of gas in
Keplerian motion around a black hole with a mass of the order of 10^9 Mo, and
one which is characterized by high, blue-shifted velocities at large lag. There
is no indication of the presence of optically thick emission medium neither in
the Lya, nor in the Civ response functions. The component characterized by
blue-shifted velocities, which is comparatively much stronger in Civ than in
Lya, is more or less compatible with being the result of gas falling towards
the central black hole with free-fall acceleration. We propose however that the
line emission at high, blue-shifted velocities is better explained in terms of
entrainment of gas clouds by the jet. This gas is therefore probably
collisionally excited as a result of heating due to the intense infrared
radiation from the jet, which would explain the strength of this component in
Civ relative to Lya. This phenomenon might be a signature of disk-jet
interaction.Comment: 16 pages, 10 figures. Accepted for publication in ApJ. Uses aaste
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