3,957 research outputs found

    Turing machines based on unsharp quantum logic

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    In this paper, we consider Turing machines based on unsharp quantum logic. For a lattice-ordered quantum multiple-valued (MV) algebra E, we introduce E-valued non-deterministic Turing machines (ENTMs) and E-valued deterministic Turing machines (EDTMs). We discuss different E-valued recursively enumerable languages from width-first and depth-first recognition. We find that width-first recognition is equal to or less than depth-first recognition in general. The equivalence requires an underlying E value lattice to degenerate into an MV algebra. We also study variants of ENTMs. ENTMs with a classical initial state and ENTMs with a classical final state have the same power as ENTMs with quantum initial and final states. In particular, the latter can be simulated by ENTMs with classical transitions under a certain condition. Using these findings, we prove that ENTMs are not equivalent to EDTMs and that ENTMs are more powerful than EDTMs. This is a notable difference from the classical Turing machines.Comment: In Proceedings QPL 2011, arXiv:1210.029

    Energy Loss Signals in the ALICE TRD

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    We present the energy loss measurements with the ALICE TRD in the βγ\beta\gamma range 1--104^{4}, where β=v/c\beta=v/c and γ=1/1β2\gamma=1/\sqrt{1-\beta^2}. The measurements are conducted in three different scenarios: 1) with pions and electrons from testbeams; 2) with protons, pions and electrons in proton-proton collisions at center-of-mass energy 7 TeV; 3) with muons detected in ALICE cosmic runs. In the testbeam and cosmic ray measurements, ionization energy loss (dE/dx) signal as well as ionization energy loss plus transition radiation (dE/dx+TR) signal are measured. With cosmic muons the onset of TR is observed. Signals from TeV cosmic muons are consistent with those from GeV electrons in the other measurements. Numerical descriptions of the signal spectra and the βγ\beta\gamma-dependence of the most probable signals are also presented.Comment: Proceedings for the 4th Workshop on Advanced Transition Radiation Detectors for Accelerator and Space Applications, 14-16 September 2011, Bari, Ital

    Adaptive DCTNet for Audio Signal Classification

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    In this paper, we investigate DCTNet for audio signal classification. Its output feature is related to Cohen's class of time-frequency distributions. We introduce the use of adaptive DCTNet (A-DCTNet) for audio signals feature extraction. The A-DCTNet applies the idea of constant-Q transform, with its center frequencies of filterbanks geometrically spaced. The A-DCTNet is adaptive to different acoustic scales, and it can better capture low frequency acoustic information that is sensitive to human audio perception than features such as Mel-frequency spectral coefficients (MFSC). We use features extracted by the A-DCTNet as input for classifiers. Experimental results show that the A-DCTNet and Recurrent Neural Networks (RNN) achieve state-of-the-art performance in bird song classification rate, and improve artist identification accuracy in music data. They demonstrate A-DCTNet's applicability to signal processing problems.Comment: International Conference of Acoustic and Speech Signal Processing (ICASSP). New Orleans, United States, March, 201

    Strong enhancement of chlorophyll a concentration by a weak typhoon

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    Recent studies demonstrate that chlorophyll a (chl a) concentrations in the surface ocean can be significantly enhanced due to typhoons. The present study investigated chl a concentrations in the middle of the South China Sea (SCS) from 1997-2007. Only the Category1 (minimal) Typhoon Hagibis (2007) had a notable effect on the chl a concentrations. Typhoon Hagibis had a strong upwelling potential due to its location near the equator, and the forcing time of the typhoon (>82 h) was much longer than the geostrophic adjustment time (~63 h). The higher upwelling velocity and the longer forcing time increased the depth of the mixed-layer, which consequently induced a strong phytoplankton bloom that accounted for about 30% of the total annual chl a concentration in the middle of the SCS. The implication is that the forcing time of a typhoon should be long enough to establish a strong upwelling and consequently for the induction of significant upper ocean responses.Comment: Typhoon-Ocean Environment interaction

    Controllable Operations of Edge States in Cross-One-dimensional Topological Chains

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    Topological edge states are recently attracting intense interest due to their robustness in the presence of disorder and defects. However, most approaches for manipulating such states require global modulations of the system's Hamiltonian. In this work, we develop a method to control edge states using local interactions of a four-node junction between cross-one-dimensional topological atomic chains. These junction interactions can give rise to tunable couplings between the hybridized edge states within different geometric symmetry, allowing us to implement robust quantum state transfer and SWAP gate between the two topological chains, where the edge states are pair-encoded as a single qubit. Moreover, when the atoms are precisely positioned to couple waveguides, the correlated decay caused by the environment enables the anti-symmetric edge states to present subradiant dynamics and thus show extremely long coherence time. These findings open up new possibilities for quantum technologies with topological edge states in the future.Comment: 7 pages, 4 figure
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