137,675 research outputs found
A solution set for fine games
Bumb and Hoede have shown that a cooperative game can be split into two games, {\it the reward game} and {\it the fine game}, by considering the sign of quantities in the c-diagram of the game. One can then define a solution for the original game as , where is a solution for the reward game and is a solution for the fine game. Due to the distinction of cooperation rewards and fines, for allocating the fines one may use another solution concept than for the rewards
The role of phosphorylation and dephosphorylation of shell matrix proteins in shell formation : an in vivo and in vitro study
Protein phosphorylation is a fundamental mechanism regulating many aspects of cellular processes. Shell matrix proteins (SMPs) control crystal nucleation, polymorphism, morphology, and organization of calcium carbonate crystallites during shell formation. SMPs phosphorylation is suggested to be important in shell formation but the mechanism is largely unknown. Here, to investigate the mechanism of phosphorylation of SMPs in biomineralization, we performed in vivo and in vitro experiment. By injection of antibody against the anti-phosphoserine/threonine /tyrosine into the extrapallial fluid of the pearl oyster Pinctada fucata, phosphorylation of matrix proteins were significantly reduced after 6 days. Newly formed prismatic layers and nacre tablet were found to grow abnormally with reduced crystallinity and possibly changed crystal orientation shown by Raman spectroscopy. In addition, regeneration of shells is also inhibited in vivo. Then, protein phosphatase was used to dephosphorylate SMPs extracted from the shells. After dephosphorylation, the ability of SMPs to inhibiting calcium carbonate formation have been reduced. Surprisingly, the ability of SMPs to modulate crystal morphology have been largely compromised although phosphorylation extent remained to be at least half of the control. Furthermore, dephosphorylation of SMPs changed the distribution of protein occlusions and decreased the amount of protein occlusions inside crystals shown by confocal imaging, indicating interaction between phosphorylated SMPs and crystals. Taken together, this study provides insight into the mechanism of phosphorylation of SMPs during shell formation
Effective medium approximation and the complex optical properties of the inhomogeneous superconductor K_{0.8}Fe_{2-y}Se_2
The in-plane optical properties of the inhomogeneous iron-chalcogenide
superconductor K_{0.8}Fe_{2-y}Se_2 with a critical temperature Tc = 31 K have
been modeled in the normal state using the Bruggeman effective medium
approximation for metallic inclusions in an insulating matrix. The volume
fraction for the inclusions is estimated to be ~ 10%; however, they appear to
be highly distorted, suggesting a filamentary network of conducting regions
joined through weak links. The value for the Drude plasma frequency in the
inclusions is much larger than the volume average, which when considered with
the reasonably low values for the scattering rate, suggests that the transport
in the grains is always metallic. Estimates for the dc conductivity and the
superfluid density in the grains places the inclusions on the universal scaling
line close to the other homogeneous iron-based superconductors.Comment: 6 pages, 3 figure
Spin squeezing: transforming one-axis-twisting into two-axis-twisting
Squeezed spin states possess unique quantum correlation or entanglement that
are of significant promises for advancing quantum information processing and
quantum metrology. In recent back to back publications [C. Gross \textit{et al,
Nature} \textbf{464}, 1165 (2010) and Max F. Riedel \textit{et al, Nature}
\textbf{464}, 1170 (2010)], reduced spin fluctuations are observed leading to
spin squeezing at -8.2dB and -2.5dB respectively in two-component atomic
condensates exhibiting one-axis-twisting interactions (OAT). The noise
reduction limit for the OAT interaction scales as , which
for a condensate with atoms, is about 100 times below standard
quantum limit. We present a scheme using repeated Rabi pulses capable of
transforming the OAT spin squeezing into the two-axis-twisting type, leading to
Heisenberg limited noise reduction , or an extra 10-fold
improvement for .Comment: 4 pages, 3 figure
New model of calculating the energy transfer efficiency for the spherical theta-pinch device
Ion-beam-plasma-interaction plays an important role in the field of Warm
Dense Matter (WDM) and Inertial Confinement Fusion (ICF). A spherical theta
pinch is proposed to act as a plasma target in various applications including a
plasma stripper cell. One key parameter for such applications is the free
electron density. A linear dependency of this density to the amount of energy
transferred into the plasma from an energy storage was found by C. Teske. Since
the amount of stored energy is known, the energy transfer efficiency is a
reliable parameter for the design of a spherical theta pinch device. The
traditional two models of energy transfer efficiency are based on assumptions
which comprise the risk of systematical errors. To obtain precise results, this
paper proposes a new model without the necessity of any assumption to calculate
the energy transfer efficiency for an inductively coupled plasma device.
Further, a comparison of these three different models is given at a fixed
operation voltage for the full range of working gas pressures. Due to the
inappropriate assumptions included in the traditional models, one owns a
tendency to overestimate the energy transfer efficiency whereas the other leads
to an underestimation. Applying our new model to a wide spread set of operation
voltages and gas pressures, an overall picture of the energy transfer
efficiency results
Fast initialization of the spin state of an electron in a quantum dot in the Voigt configuration
We consider the initialization of the spin-state of a single electron trapped
in a self-assembled quantum dot via optical pumping of a trion level. We show
that with a magnetic field applied perpendicular to the growth direction of the
dot, a near-unity fidelity can be obtained in a time equal to a few times the
inverse of the spin-conserving trion relaxation rate. This method is several
orders-of-magnitude faster than with the field aligned parallel, since this
configuration must rely on a slow hole spin-flip mechanism. This increase in
speed does result in a limit on the maximum obtainable fidelity, but we show
that for InAs dots, the error is very small.Comment: 4 pages, 4 figure
Non-adiabatic Holonomic Gates realized by a single-shot implementation
Non-adiabatic holonomic quantum computation has received increasing attention
due to its robustness against control errors. However, all the previous schemes
have to use at least two sequentially implemented gates to realize a general
one-qubit gate. In this paper, we put forward a novelty scheme by which one can
directly realize an arbitrary holonomic one-qubit gate with a single-shot
implementation, avoiding the extra work of combining two gates into one. Based
on a three-level model driven by laser pulses, we show that any single-qubit
holonomic gate can be realized by varying the detuning, amplitude, and phase of
lasers. Our scheme is compatible with previously proposed non-adiabatic
holonomic two-qubit gates, combining with which the arbitrary holonomic
one-qubit gates can play universal non-adiabatic holonomic quantum computation.
We also investigate the effects of some unavoidable realistic errors on our
scheme.Comment: 5 pages, 2 figure
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