2,960 research outputs found
Efficient Code for Relativistic Quantum Summoning
Summoning retrieves quantum information, prepared somewhere in spacetime, at
another specified point in spacetime, but this task is limited by the quantum
no-cloning principle and the speed-of-light bound. We develop a thorough
mathematical framework for summoning quantum information in a relativistic
system and formulate a quantum summoning protocol for any valid configuration
of causal diamonds in spacetime. For single-qubit summoning, we present a
protocol based on a Calderbank-Shor-Steane code that decreases the space
complexity for encoding by a factor of two compared to the previous best result
and reduces the gate complexity from scaling as the cube to the square of the
number of causal diamonds. Our protocol includes decoding whose gate complexity
scales linearly with the number of causal diamonds. Our thorough framework for
quantum summoning enables full specification of the protocol, including spatial
and temporal implementation and costs, which enables quantum summoning to be a
well posed protocol for relativistic quantum communication purposes.Comment: 15 pages, 7 figure
Nuclear-nuclear interaction mediated by a mechanically controlled nitrogen-vacancy-center spin in diamond
We propose a scheme to achieve nuclear-nuclear indirect interactions mediated
by a mechanically driven nitrogen-vacancy (NV) center in diamond. Here we
demonstrate two-qubit entangling gates and quantum-state transfer between two
carbon nuclei in diamond. In such a system, the NV center interacts with a
nearby nuclear spin via a dipole-dipole interaction. Under the quantum Zeno
condition, the scheme is robust against decoherence caused by coupling between
the NV center (nuclear spins) and the environment. Conveniently, precise
control of dipole coupling is not required so this scheme is insensitive to
fluctuating positions of the nuclear spins and the NV center. Our scheme
provides a general blueprint for multi-nuclear-spin gates and for multi-party
communication in a polygon geometry with each vertex occupied by a nuclear
spin.Comment: 11 pages, 8 figure
Molecular evolution of the keratin associated protein gene family in mammals, role in the evolution of mammalian hair
Correction to Wu DD, Irwin DM, Zhang YP: Molecular evolution of the keratin associated protein gene family in mammals, role in the evolution of mammalian hair. BMC Evol Biol 2008, 8:241
MSSM Anatomy of the Polarization Puzzle in B --> phi K* Decays
We analyze the polarization puzzle in the Minimal
Supersymmetric Standard Model (MSSM) including the neutral Higgs boson (NHB)
contributions. To calculate the non-factorizable contributions to hadronic
matrix elements of operators, we have used the QCD factorization framework to
the order. It is shown that the recent experimental results of the
polarization fractions in decays, which are difficult to be
explained in SM, could be explained in MSSM if there are flavor non-diagonal
squark mass matrix elements of 2nd and 3rd generations, which also satisfy all
relevant constraints from known experiments (, etc.). We have shown
in details that the experimental results can be accommodated with the flavor
non-diagonal mass insertion of chirality RL, RL+LR, RR, or LL+ RR when the NHB
contributions as well as corrections of hadronic matrix
elements of operators are included. However the branching ratios for the decay
are smaller than the experimental measurements.Comment: 15 pages, 5 figures, minor revision and references adde
Efficient code for relativistic quantum summoning
Summoning retrieves quantum information, prepared somewhere in spacetime, at another specified point in spacetime, but this task is limited by the quantum no-cloning principle and the speed-of-light bound. We develop a thorough mathematical framework for summoning quantum information in a relativistic system and formulate a quantum summoning protocol for any valid configuration of causal diamonds in spacetime. For single-qubit summoning, we present a protocol based on a Calderbank–Shor–Steane code that decreases the space complexity for encoding by a factor of two compared to the previous best result and reduces the gate complexity from scaling as the cube to the square of the number of causal diamonds. Our protocol includes decoding whose gate complexity scales linearly with the number of causal diamonds. Our thorough framework for quantum summoning enables full specification of the protocol, including spatial and temporal implementation and costs, which enables quantum summoning to be a well posed protocol for relativistic quantum communication purposes
Multi-Locus Analysis Reveals A Different Pattern of Genetic Diversity for Mitochondrial and Nuclear DNA between Wild and Domestic Pigs in East Asia
BACKGROUND: A major reduction of genetic diversity in mtDNA occurred during the domestication of East Asian pigs. However, the extent to which genetic diversity has been lost in the nuclear genome is uncertain. To reveal levels and patterns of nucleotide diversity and to elucidate the genetic relationships and demographic history of domestic pigs and their ancestors, wild boars, we investigated 14 nuclear markers (including 8 functional genes, 2 pseudogenes and 4 intergenic regions) from 11 different chromosomes in East Asia-wide samples and pooled them with previously obtained mtDNA data for a combined analysis. PRINCIPAL FINDINGS: The results indicated that domestic pigs and wild boars possess comparable levels of nucleotide diversity across the nuclear genome, which is inconsistent with patterns that have been found in mitochondrial genome. CONCLUSIONS: This incongruence between the mtDNA and nuclear genomes is suggestive of a large-scale backcross between male wild boars and female domestic pigs in East Asia. Our data reveal the impacts of founder effects and backcross on the pig genome and help us better understand the complex demographic histories of East Asian pigs, which will be useful for future work on artificial selection
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