25,131 research outputs found
Practical Certificateless Aggregate Signatures From Bilinear Maps
Aggregate signature is a digital signature with a striking property that anyone can aggregate n individual signatures on n different messages which are signed by n distinct signers, into a single compact signature to reduce computational and storage costs. In this work, two practical certificateless aggregate signature schemes are proposed from bilinear maps. The first scheme CAS-1 reduces the costs of communication and signer-side computation but trades off the storage, while CAS-2 minimizes the storage but sacrifices the communication costs. One can choose either of the schemes by consideration of the application requirement. Compare with ID-based schemes, our schemes do not entail public key certificates as well and achieve the trust level 3, which imply the frauds of the authority are detectable. Both of the schemes are proven secure in the random oracle model by assuming the intractability of the computational Diffie-Hellman problem over the groups with bilinear maps, where the forking lemma technique is avoided
Self-consistent relativistic quasiparticle random-phase approximation and its applications to charge-exchange excitations and -decay half-lives
The self-consistent quasiparticle random-phase approximation (QRPA) approach
is formulated in the canonical single-nucleon basis of the relativistic
Hatree-Fock-Bogoliubov (RHFB) theory. This approach is applied to study the
isobaric analog states (IAS) and Gamov-Teller resonances (GTR) by taking Sn
isotopes as examples. It is found that self-consistent treatment of the
particle-particle residual interaction is essential to concentrate the IAS in a
single peak for open-shell nuclei and the Coulomb exchange term is very
important to predict the IAS energies. For the GTR, the isovector pairing can
increase the calculated GTR energy, while the isoscalar pairing has an
important influence on the low-lying tail of the GT transition. Furthermore,
the QRPA approach is employed to predict nuclear -decay half-lives. With
an isospin-dependent pairing interaction in the isoscalar channel, the
RHFB+QRPA approach almost completely reproduces the experimental -decay
half-lives for nuclei up to the Sn isotopes with half-lives smaller than one
second. Large discrepancies are found for the Ni, Zn, and Ge isotopes with
neutron number smaller than , as well as the Sn isotopes with neutron
number smaller than . The potential reasons for these discrepancies are
discussed in detail.Comment: 34 pages, 14 figure
Quantum Transport Simulation of III-V TFETs with Reduced-Order K.P Method
III-V tunneling field-effect transistors (TFETs) offer great potentials in
future low-power electronics application due to their steep subthreshold slope
and large "on" current. Their 3D quantum transport study using non-equilibrium
Green's function method is computationally very intensive, in particular when
combined with multiband approaches such as the eight-band K.P method. To reduce
the numerical cost, an efficient reduced-order method is developed in this
article and applied to study homojunction InAs and heterojunction GaSb-InAs
nanowire TFETs. Device performances are obtained for various channel widths,
channel lengths, crystal orientations, doping densities, source pocket lengths,
and strain conditions
Analysis of the X(1576) as a tetraquark state with the QCD sum rules
In this letter, we take the point of view that the X(1576) be tetraquark
state which consists of a scalar-diquark and an anti-scalar-diquark in relative
-wave, and calculate its mass in the framework of the QCD sum rules
approach. The numerical value of the mass is
consistent with the experimental data, there may be some tetraquark component
in the vector meson X(1576).Comment: 6 pages, 1 figure, second version, typos correcte
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