46,814 research outputs found
Direction-of-Arrival Estimation Based on Sparse Recovery with Second-Order Statistics
Traditional direction-of-arrival (DOA) estimation techniques perform Nyquist-rate sampling of the received signals and as a result they require high storage. To reduce sampling ratio, we introduce level-crossing (LC) sampling which captures samples whenever the signal crosses predetermined reference levels, and the LC-based analog-to-digital converter (LC ADC) has been shown to efficiently sample certain classes of signals. In this paper, we focus on the DOA estimation problem by using second-order statistics based on the LC samplings recording on one sensor, along with the synchronous samplings of the another sensors, a sparse angle space scenario can be found by solving an minimization problem, giving the number of sources and their DOA's. The experimental results show that our proposed method, when compared with some existing norm-based constrained optimization compressive sensing (CS) algorithms, as well as subspace method, improves the DOA estimation performance, while using less samples when compared with Nyquist-rate sampling and reducing sensor activity especially for long time silence signal
Quantum mechanical photon-count formula derived by entangled state representation
By introducing the thermo entangled state representation, we derived four new
photocount distribution formulas for a given density operator of light field.
It is shown that these new formulas, which is convenient to calculate the
photocount, can be expressed as such integrations over Laguree-Gaussian
function with characteristic function, Wigner function, Q-function, and
P-function, respectively.Comment: 5 pages, no figur
Entangled Husimi distribution and Complex Wavelet transformation
Based on the proceding Letter [Int. J. Theor. Phys. 48, 1539 (2009)], we
expand the relation between wavelet transformation and Husimi distribution
function to the entangled case. We find that the optical complex wavelet
transformation can be used to study the entangled Husimi distribution function
in phase space theory of quantum optics. We prove that the entangled Husimi
distribution function of a two-mode quantum state |phi> is just the modulus
square of the complex wavelet transform of exp{-(|eta|^2)/2} with phi(eta)being
the mother wavelet up to a Gaussian function.Comment: 7 page
Generalized thermo vacuum state derived by the partial trace method
By virtue of the technique of integration within an ordered product (IWOP) of
operators we present a new approach for deriving generalized thermo vacuum
state which is simpler in form that the result by using the Umezawa-Takahashi
approach, in this way the thermo field dynamics can be developed. Applications
of the new state are discussed.Comment: 5 pages, no figure, revtex
Influence of tensor interactions on masses and decay widths of dibaryons
The influence of gluon and Goldstone boson induced tensor interactions on the
dibaryon masses and D-wave decay widths has been studied in the quark
delocalization, color screening model. The effective S-D wave transition
interactions induced by gluon and Goldstone boson exchanges decrease rapidly
with increasing strangeness of the channel. The tensor contribution of K and
mesons is negligible in this model. There is no six-quark state in the
light flavor world studied so far that can become bound by means of these
tensor interactions besides the deuteron. The partial D-wave decay widths of
the N state to spin 0 and 1 final states
are 12.0 keV and 21.9 keV respectively. This is a very narrow dibaryon
resonance that might be detectable in relativistic heavy ion reactions by
existing RHIC detectors through the reconstruction of the vertex mass of the
decay product and by the COMPAS detector at CERN or at JHF in
Japan and the FAIR project in Germany in the future.Comment: 19 pages, 5 figure
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