3,329 research outputs found
Generalized X states of N qubits and their symmetries
Several families of states such as Werner states, Bell-diagonal states and
Dicke states are useful to understand multipartite entanglement. Here we
present a [2^(N+1)-1]-parameter family of N-qubit "X states" that embrace all
those families, generalizing previously defined states for two qubits. We also
present the algebra of the operators that characterize the states and an
iterative construction for this algebra, a sub-algebra of su(2^(N)). We show
how a variety of entanglement witnesses can detect entanglement in such states.
Connections are also made to structures in projective geometry.Comment: 4 pages, 2 figure
Second post-Newtonian gravitational radiation reaction for two-body systems: Nonspinning bodies
Starting from the recently obtained 2PN accurate forms of the energy and
angular momentum fluxes from inspiralling compact binaries, we deduce the
gravitational radiation reaction to 2PN order beyond the quadrupole
approximation - 4.5PN terms in the equation of motion - using the refined
balance method proposed by Iyer and Will. We explore critically the features of
their construction and illustrate them by contrast to other possible variants.
The equations of motion are valid for general binary orbits and for a class of
coordinate gauges. The limiting cases of circular orbits and radial infall are
also discussed.Comment: 38 pages, REVTeX, no figures, to appear in Phys. Rev.
SubSpectralNet - Using Sub-Spectrogram based Convolutional Neural Networks for Acoustic Scene Classification
Acoustic Scene Classification (ASC) is one of the core research problems in
the field of Computational Sound Scene Analysis. In this work, we present
SubSpectralNet, a novel model which captures discriminative features by
incorporating frequency band-level differences to model soundscapes. Using
mel-spectrograms, we propose the idea of using band-wise crops of the input
time-frequency representations and train a convolutional neural network (CNN)
on the same. We also propose a modification in the training method for more
efficient learning of the CNN models. We first give a motivation for using
sub-spectrograms by giving intuitive and statistical analyses and finally we
develop a sub-spectrogram based CNN architecture for ASC. The system is
evaluated on the public ASC development dataset provided for the "Detection and
Classification of Acoustic Scenes and Events" (DCASE) 2018 Challenge. Our best
model achieves an improvement of +14% in terms of classification accuracy with
respect to the DCASE 2018 baseline system. Code and figures are available at
https://github.com/ssrp/SubSpectralNetComment: Accepted to IEEE International Conference on Acoustics, Speech, and
Signal Processing (ICASSP) 201
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