40,035 research outputs found
Investigation of Frame Alignments for GMM-based Digit-prompted Speaker Verification
Frame alignments can be computed by different methods in GMM-based speaker
verification. By incorporating a phonetic Gaussian mixture model (PGMM), we are
able to compare the performance using alignments extracted from the deep neural
networks (DNN) and the conventional hidden Markov model (HMM) in digit-prompted
speaker verification. Based on the different characteristics of these two
alignments, we present a novel content verification method to improve the
system security without much computational overhead. Our experiments on the
RSR2015 Part-3 digit-prompted task show that, the DNN based alignment performs
on par with the HMM alignment. The results also demonstrate the effectiveness
of the proposed Kullback-Leibler (KL) divergence based scoring to reject speech
with incorrect pass-phrases.Comment: accepted by APSIPA ASC 201
Ultracold Dipolar Gas of Fermionic NaK Molecules in their Absolute Ground State
We report on the creation of an ultracold dipolar gas of fermionic
NaK molecules in their absolute rovibrational and hyperfine
ground state. Starting from weakly bound Feshbach molecules, we demonstrate
hyperfine resolved two-photon transfer into the singlet ground state, coherently bridging a binding energy
difference of 0.65 eV via stimulated rapid adiabatic passage. The
spin-polarized, nearly quantum degenerate molecular gas displays a lifetime
longer than 2.5 s, highlighting NaK's stability against two-body chemical
reactions. A homogeneous electric field is applied to induce a dipole moment of
up to 0.8 Debye. With these advances, the exploration of many-body physics with
strongly dipolar Fermi gases of NaK molecules is in experimental
reach.Comment: 5 pages, 5 figure
Two-Photon Pathway to Ultracold Ground State Molecules of NaK
We report on high-resolution spectroscopy of ultracold fermionic
\nak~Feshbach molecules, and identify a two-photon pathway to the rovibrational
singlet ground state via a resonantly mixed \Bcres intermediate state.
Photoassociation in a Na-K atomic mixture and one-photon
spectroscopy on \nak~Feshbach molecules reveal about 20 vibrational levels of
the electronically excited \ctrip state. Two of these levels are found to be
strongly perturbed by nearby \Bsing states via spin-orbit coupling, resulting
in additional lines of dominant singlet character in the perturbed complex
{}, or of
resonantly mixed character in {}. The dominantly singlet level is used to locate
the absolute rovibrational singlet ground state via Autler-Townes spectroscopy. We demonstrate coherent
two-photon coupling via dark state spectroscopy between the predominantly
triplet Feshbach molecular state and the singlet ground state. Its binding
energy is measured to be 5212.0447(1) \cm, a thousand-fold improvement in
accuracy compared to previous determinations. In their absolute singlet ground
state, \nak~molecules are chemically stable under binary collisions and possess
a large electric dipole moment of Debye. Our work thus paves the way
towards the creation of strongly dipolar Fermi gases of NaK molecules.Comment: 23 pages, 8 figure
Resonant Higgs boson pair production in the decay channel
Adding a scalar singlet provides one of the simplest extensions of the
Standard Model. In this work we briefly review the latest constraints on the
mass and mixing of the new Higgs boson and study its production and decay at
the LHC. We mainly focus on double Higgs production in the decay channel.
This decay is found to be efficient in a region of masses of the heavy Higgs
boson of 260 - 500 GeV, so it is complementary to the 4 channel, more
efficient for Higgs bosons having masses greater than 500 GeV. We analyse this
di-leptonic decay channel in detail using kinematic variables such as and the -assisted on-shell reconstruction of invisible
momenta. Using proper cuts, a significance of 3 for 3000
fb can be achieved at the 14 TeV LHC for = 260 - 400 GeV if the
mixing is close to its present limit and . Smaller mixing values would require combining various decay channels in
order to reach a similar significance. The complementarity among , and channels is
studied for arbitrary values.Comment: 36 pages, 13 figure
Supergravity duals of gauge theories from F(4) gauged supergravity in six dimensions
We construct supergravity solutions dual to twisted field theories that are
the worldvolume theories of D4-branes wrapped on 2, 3-cycles, and NS-fivebranes
on 3-cycles. We first obtain the solutions for the Romans' six-dimensional
gauged supergravity theories and then up-lift them to ten dimensions. In
particular, we find solutions for field configurations with either non-Abelian
fields or B-fields being excited. One of these solutions, in the massless case,
is up-lifted to the massless type IIA string theory. This is the first example
of such a kind. The cases studied provide new examples of the AdS/CFT duality
involving twisted field theories.Comment: 26 pages, 3 figures, minor changes and references added to match the
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