437 research outputs found
Numerical Analysis of Quasiholes of the Moore-Read Wavefunction
We demonstrate numerically that non-Abelian quasihole excitations of the fractional quantum Hall state have some of the key properties necessary
to support quantum computation. We find that as the quasihole spacing is
increased, the unitary transformation which describes winding two quasiholes
around each other converges exponentially to its asymptotic limit and that the
two orthogonal wavefunctions describing a system with four quasiholes become
exponentially degenerate. We calculate the length scales for these two decays
to be and
respectively. Additionally we determine which fusion channel is lower in energy
when two quasiholes are brought close together.Comment: 4 pages, 3 figure
Resources Required for Topological Quantum Factoring
We consider a hypothetical topological quantum computer where the qubits are
comprised of either Ising or Fibonacci anyons. For each case, we calculate the
time and number of qubits (space) necessary to execute the most computationally
expensive step of Shor's algorithm, modular exponentiation. For Ising anyons,
we apply Bravyi's distillation method [S. Bravyi, Phys. Rev. A 73, 042313
(2006)] which combines topological and non-topological operations to allow for
universal quantum computation. With reasonable restrictions on the physical
parameters we find that factoring a 128 bit number requires approximately 10^3
Fibonacci anyons versus at least 3 x 10^9 Ising anyons. Other distillation
algorithms could reduce the resources for Ising anyons substantially.Comment: 4+epsilon pages, 4 figure
Resource-saving technologies
All that is routinely used by mankind, from electric lighting to flat-screen TV sets and iPhone - depends on our ability to pump out of the Earth's resources. Modern life of humanity is depend on the expense of natural resources.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3105
Epilepsy, Behavioral Abnormalities, and Physiological Comorbidities in Syntaxin-Binding Protein 1 (STXBP1) Mutant Zebrafish.
Mutations in the synaptic machinery gene syntaxin-binding protein 1, STXBP1 (also known as MUNC18-1), are linked to childhood epilepsies and other neurodevelopmental disorders. Zebrafish STXBP1 homologs (stxbp1a and stxbp1b) have highly conserved sequence and are prominently expressed in the larval zebrafish brain. To understand the functions of stxbp1a and stxbp1b, we generated loss-of-function mutations using CRISPR/Cas9 gene editing and studied brain electrical activity, behavior, development, heart physiology, metabolism, and survival in larval zebrafish. Homozygous stxbp1a mutants exhibited a profound lack of movement, low electrical brain activity, low heart rate, decreased glucose and mitochondrial metabolism, and early fatality compared to controls. On the other hand, homozygous stxbp1b mutants had spontaneous electrographic seizures, and reduced locomotor activity response to a movement-inducing "dark-flash" visual stimulus, despite showing normal metabolism, heart rate, survival, and baseline locomotor activity. Our findings in these newly generated mutant lines of zebrafish suggest that zebrafish recapitulate clinical phenotypes associated with human syntaxin-binding protein 1 mutations
Non-Abelian statistics as a Berry phase in exactly solvable models
We demonstrate how to directly study non-Abelian statistics for a wide class
of exactly solvable many-body quantum systems. By employing exact eigenstates
to simulate the adiabatic transport of a model's quasiparticles, the resulting
Berry phase provides a direct demonstration of their non-Abelian statistics. We
apply this technique to Kitaev's honeycomb lattice model and explicitly
demonstrate the existence of non-Abelian Ising anyons confirming the previous
conjectures. Finally, we present the manipulations needed to transport and
detect the statistics of these quasiparticles in the laboratory. Various
physically realistic system sizes are considered and exact predictions for such
experiments are provided.Comment: 10 pages, 3 figures. To appear in New Journal of Physic
Photodissociation transition states characterized by chirped pulse millimeter wave spectroscopy.
The 193-nm photolysis of CH2CHCN illustrates the capability of chirped-pulse Fourier transform millimeter-wave spectroscopy to characterize transition states. We investigate the HCN, HNC photofragments in highly excited vibrational states using both frequency and intensity information. Measured relative intensities of J = 1-0 rotational transition lines yield vibrational-level population distributions (VPD). These VPDs encode the properties of the parent molecule transition state at which the fragment molecule was born. A Poisson distribution formalism, based on the generalized Franck-Condon principle, is proposed as a framework for extracting information about the transition-state structure from the observed VPD. We employ the isotopologue CH2CDCN to disentangle the unimolecular 3-center DCN elimination mechanism from other pathways to HCN. Our experimental results reveal a previously unknown transition state that we tentatively associate with the HCN eliminated via a secondary, bimolecular reaction
Anisotropic Instabilities in Trapped Spinor Bose-Einstein Condensates
We theoretically investigate the effect of an anisotropic trap on the
instability of the polar phase of a spin-1 Bose-Einstein condensate.
By considering rigorously the spatial quantization, we show that the growth of
the nascent ferromagnetic phase at short times becomes anisotropic with
stronger oscillations in the magnetization correlation function along the
unconfined direction.Comment: 8 pages, 6 figure
Discovery of SiCSi in IRC+10216: A missing link between gas and dust carriers of SiC bonds
We report the discovery in space of a disilicon species, SiCSi, from
observations between 80 and 350 GHz with the IRAM 30m radio telescope. Owing to
the close coordination between laboratory experiments and astrophysics, 112
lines have now been detected in the carbon-rich star CWLeo. The derived
frequencies yield improved rotational and centrifugal distortion constants up
to sixth order. From the line profiles and interferometric maps with the
Submillimeter Array, the bulk of the SiCSi emis- sion arises from a region of 6
arcseconds in radius. The derived abundance is comparable to that of SiC2. As
expected from chemical equilibrium calculations, SiCSi and SiC2 are the most
abundant species harboring a SiC bond in the dust formation zone and certainly
both play a key role in the formation of SiC dust grains.Comment: To be published in the Astrophysical Journal Letters; Accepted May 6
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Selective role of the translin/trax RNase complex in hippocampal synaptic plasticity
Activity-dependent local protein synthesis is critical for synapse-specific, persistent plasticity. Abnormalities in local protein synthesis have been implicated in psychiatric disorders. We have recently identified the translin/trax microRNA-degrading enzyme as a novel mediator of protein synthesis at activated synapses. Additionally, translin knockout (KO) mice, which lack translin/trax, exhibit some of the behavioral abnormalities found in a mouse model of fragile X syndrome (fragile X mental retardation protein-FMRP-KO mice). Therefore, identifying signaling pathways interacting with translin/trax to support persistent synaptic plasticity is a translationally relevant goal. Here, as a first step to achieve this goal, we have assessed the requirement of translin/trax for multiple hippocampal synaptic plasticity paradigms that rely on distinct molecular mechanisms. We found that mice lacking translin/trax exhibited selective impairment in a form of persistent hippocampal plasticity, which requires postsynaptic protein kinase A (PKA) activity. In contrast, enduring forms of plasticity that are dependent on presynaptic PKA were unaffected. Furthermore, these mice did not display exaggerated metabotropic glutamate receptor-mediated long-term synaptic depression (mGluR-LTD), a hallmark of the FMRP KO mice. On the contrary, translin KO mice exhibited deficits in N-methyl-d-aspartate receptor (NMDAR) dependent LTD, a phenotype not observed in the FMRP knockouts. Taken together, these findings demonstrate that translin/trax mediates long-term synaptic plasticity that is dependent on postsynaptic PKA signaling and suggest that translin/trax and FMRP play distinct roles in hippocampal synaptic plasticity
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