206 research outputs found
Analysis of two-player quantum games in an EPR setting using geometric algebra
The framework for playing quantum games in an Einstein-Podolsky-Rosen (EPR)
type setting is investigated using the mathematical formalism of Clifford
geometric algebra (GA). In this setting, the players' strategy sets remain
identical to the ones in the classical mixed-strategy version of the game,
which is then obtained as proper subset of the corresponding quantum game. As
examples, using GA we analyze the games of Prisoners' Dilemma and Stag Hunt
when played in the EPR type setting.Comment: 20 pages, no figure, revise
N-player quantum games in an EPR setting
The -player quantum game is analyzed in the context of an
Einstein-Podolsky-Rosen (EPR) experiment. In this setting, a player's
strategies are not unitary transformations as in alternate quantum
game-theoretic frameworks, but a classical choice between two directions along
which spin or polarization measurements are made. The players' strategies thus
remain identical to their strategies in the mixed-strategy version of the
classical game. In the EPR setting the quantum game reduces itself to the
corresponding classical game when the shared quantum state reaches zero
entanglement. We find the relations for the probability distribution for
-qubit GHZ and W-type states, subject to general measurement directions,
from which the expressions for the mixed Nash equilibrium and the payoffs are
determined. Players' payoffs are then defined with linear functions so that
common two-player games can be easily extended to the -player case and
permit analytic expressions for the Nash equilibrium. As a specific example, we
solve the Prisoners' Dilemma game for general . We find a new
property for the game that for an even number of players the payoffs at the
Nash equilibrium are equal, whereas for an odd number of players the
cooperating players receive higher payoffs.Comment: 26 pages, 2 figure
The Major Yolk Protein Vitellogenin Interferes with the Anti-Plasmodium Response in the Malaria Mosquito Anopheles gambiae
Functional gene analysis in malaria mosquitoes reveals molecules underpinning the trade-off between efficient reproduction and the antiparasitic response
WIMP dark matter, Higgs exchange and DAMA
In the WIMP scenario, there is a one-to-one relation between the dark matter
(DM) relic density and spin independent direct detection rate if both the
annihilation of DM and its elastic scattering on nuclei go dominantly through
Higgs exchange. In particular, for DM masses much smaller than the Higgs boson
mass, the ratio of the relevant cross sections depends only on the DM mass.
Assuming DM mass and direct detection rate within the ranges allowed by the
recent DAMA collaboration results -taking account of the channelling effect on
energy threshold and the null results of the other direct detection
experiments- gives a definite range for the relic density. For scalar DM
models, like the Higgs portal models or the inert doublet model, the relic
density range turns out to be in agreement with WMAP. This scenario implies
that the Higgs boson has a large branching ratio to pairs of DM particles, a
prediction which might challenge its search at the LHC.Comment: 5 pages, 5 figures. Matches the published version. One figure
modified. Conclusions unchange
Search for tau -> e gamma decay at Belle
We have searched for the lepton-flavor-violating decay tau -> e gamma using a
data sample of 86.7/fb collected with the Belle detector at the KEKB asymmetric
e^+ e^- collider. No evidence for a signal is obtained, and we set an upper
limit for the branching fraction Br(tau -> e gamma) < 3.9 x 10^-7 at the 90%
C.L.Comment: 11 pages, 10 figures, ReVTeX4, eps
First Observation of CP Violation in B0->D(*)CP h0 Decays by a Combined Time-Dependent Analysis of BaBar and Belle Data
We report a measurement of the time-dependent CP asymmetry of B0->D(*)CP h0
decays, where the light neutral hadron h0 is a pi0, eta or omega meson, and the
neutral D meson is reconstructed in the CP eigenstates K+ K-, K0S pi0 or K0S
omega. The measurement is performed combining the final data samples collected
at the Y(4S) resonance by the BaBar and Belle experiments at the
asymmetric-energy B factories PEP-II at SLAC and KEKB at KEK, respectively. The
data samples contain ( 471 +/- 3 ) x 10^6 BB pairs recorded by the BaBar
detector and ( 772 +/- 11 ) x 10^6, BB pairs recorded by the Belle detector. We
measure the CP asymmetry parameters -eta_f S = +0.66 +/- 0.10 (stat.) +/- 0.06
(syst.) and C = -0.02 +/- 0.07 (stat.) +/- 0.03 (syst.). These results
correspond to the first observation of CP violation in B0->D(*)CP h0 decays.
The hypothesis of no mixing-induced CP violation is excluded in these decays at
the level of 5.4 standard deviations.Comment: 9 pages, 2 figures, submitted to Physical Review Letter
Polymorphic Structures of Alzheimer's β-Amyloid Globulomers
Misfolding and self-assembly of Amyloid-β (Aβ) peptides into amyloid fibrils is pathologically linked to the development of Alzheimer's disease. Polymorphic Aβ structures derived from monomers to intermediate oligomers, protofilaments, and mature fibrils have been often observed in solution. Some aggregates are on-pathway species to amyloid fibrils, while the others are off-pathway species that do not evolve into amyloid fibrils. Both on-pathway and off-pathway species could be biologically relevant species. But, the lack of atomic-level structural information for these Aβ species leads to the difficulty in the understanding of their biological roles in amyloid toxicity and amyloid formation.Here, we model a series of molecular structures of Aβ globulomers assembled by monomer and dimer building blocks using our peptide-packing program and explicit-solvent molecular dynamics (MD) simulations. Structural and energetic analysis shows that although Aβ globulomers could adopt different energetically favorable but structurally heterogeneous conformations in a rugged energy landscape, they are still preferentially organized by dynamic dimeric subunits with a hydrophobic core formed by the C-terminal residues independence of initial peptide packing and organization. Such structural organizations offer high structural stability by maximizing peptide-peptide association and optimizing peptide-water solvation. Moreover, curved surface, compact size, and less populated β-structure in Aβ globulomers make them difficult to convert into other high-order Aβ aggregates and fibrils with dominant β-structure, suggesting that they are likely to be off-pathway species to amyloid fibrils. These Aβ globulomers are compatible with experimental data in overall size, subunit organization, and molecular weight from AFM images and H/D amide exchange NMR.Our computationally modeled Aβ globulomers provide useful insights into structure, dynamics, and polymorphic nature of Aβ globulomers which are completely different from Aβ fibrils, suggesting that these globulomers are likely off-pathway species and explaining the independence of the aggregation kinetics between Aβ globulomers and fibrils
Measurement of branching fractions and direct asymmetries for and decays at Belle II
We report measurements of the branching fractions and direct
asymmetries of the decays , , , and , and use these for testing the standard
model through an isospin-based sum rule. In addition, we measure the branching
fraction and direct asymmetry of the decay and
the branching fraction of the decay . The data are
collected with the Belle II detector from collisions at the
resonance produced by the SuperKEKB asymmetric-energy collider
and contain bottom-antibottom meson pairs. Signal yields are
determined in two-dimensional fits to background-discriminating variables, and
range from 500 to 3900 decays, depending on the channel. We obtain for the sum rule, in agreement with the standard model
expectation of zero and with a precision comparable to the best existing
determinations
Measurement of asymmetries in decays with Belle II
We present a measurement of time-dependent rate asymmetries in decays to search for non-standard-model physics in transitions. The data sample is collected with the Belle II
detector at the SuperKEKB asymmetric-energy collider in 2019-2022
and contains bottom-antibottom mesons from
resonance decays. We reconstruct signal events and
extract the charge-parity () violating parameters from a fit to the
distribution of the proper-decay-time difference of the two mesons. The
measured direct and mixing-induced asymmetries are
and , respectively, where the first
uncertainties are statistical and the second are systematic. The results are
compatible with the asymmetries observed in
transitions
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