16,008 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
Efficient Scheme for Perfect Collective Einstein-Podolsky-Rosen Steering
A practical scheme for the demonstration of perfect one-sided
device-independent quantum secret sharing is proposed. The scheme involves a
three-mode optomechanical system in which a pair of independent cavity modes is
driven by short laser pulses and interact with a movable mirror. We demonstrate
that by tuning the laser frequency to the blue (anti-Stokes) sideband of the
average frequency of the cavity modes, the modes become mutually coherent and
then may collectively steer the mirror mode to a perfect
Einstein-Podolsky-Rosen state. The scheme is shown to be experimentally
feasible, it is robust against the frequency difference between the modes,
mechanical thermal noise and damping, and coupling strengths of the cavity
modes to the mirror.Comment: 9 pages, 4 figure
The Sorting Index and Permutation Codes
In the combinatorial study of the coefficients of a bivariate polynomial that
generalizes both the length and the reflection length generating functions for
finite Coxeter groups, Petersen introduced a new Mahonian statistic ,
called the sorting index. Petersen proved that the pairs of statistics
and have the same joint distribution over
the symmetric group, and asked for a combinatorial proof of this fact. In
answer to the question of Petersen, we observe a connection between the sorting
index and the B-code of a permutation defined by Foata and Han, and we show
that the bijection of Foata and Han serves the purpose of mapping
to . We also give a type analogue of the
Foata-Han bijection, and we derive the quidistribution of and over signed
permutations. So we get a combinatorial interpretation of Petersen's
equidistribution of and . Moreover, we show that
the six pairs of set-valued statistics ,
, , ,
and are equidistributed over signed
permutations. For Coxeter groups of type , Petersen showed that the two
statistics and are equidistributed. We introduce two statistics
and for elements of and we prove that the two
pairs of statistics and are
equidistributed.Comment: 25 page
Energy Spectra of Anti-nucleons in Finite Nuclei
The quantum vacuum in a many-body system of finite nuclei has been
investigated within the relativistic Hartree approach which describes the bound
states of nucleons and anti-nucleons consistently. The contributions of the
Dirac sea to the source terms of the meson-field equations are taken into
account up to the one-nucleon loop and one-meson loop. The tensor couplings for
the - and -meson are included in the model. The overall nucleon
spectra of shell-model states are in agreement with the data. The calculated
anti-nucleon spectra in the vacuum differ about 20 -- 30 MeV with and without
the tensor-coupling effects.Comment: 4 pages, to appear in the Proceedings of MENU 2004 (Beijing, Aug. 29
-- Sept. 4, 2004
Ideal switching effect in periodic spin-orbit coupling structures
An ideal switching effect is discovered in a semiconductor nanowire with a
spatially-periodic Rashba structure. Bistable `ON' and `OFF' states can be
realized by tuning the gate voltage applied on the Rashba regions. The energy
range and position of `OFF' states can be manipulated effectively by varying
the strength of the spin-orbit coupling (SOC) and the unit length of the
periodic structure, respectively. The switching effect of the nanowire is found
to be tolerant of small random fluctuations of SOC strength in the periodic
structure. This ideal switching effect might be applicable in future spintronic
devices.Comment: 4 pages and 4 figure
Two-path succussive relaying with hybrid demodulate and forward
This is the author accepted manuscript. The final version is available from IEEE via the DOI in this recordThis paper proposes a novel demodulation-and-forward (DMF) scheme for the two-path succussive relay system. While the two-path relaying avoids the data rate loss that occurs in many one-relay cooperative systems, its performance is severely limited by interrelay interference. In this paper, we propose a hybrid DMF scheme for the two-path relay system so that the relays can switch between direct and differential demodulation modes according to channel conditions. The hybrid DMF scheme not only performs better than existing two-path approaches but is easy to achieve synchronization at the relays as well, which is particularly important as a relay receives signals from both the source and the other relay. The proposed hybrid DMF scheme provides an innovative way to implement the two-path relaying scheme.This work was supported by
the Important National Science and Technology Specific Projects of China
under Grant 2011ZX03004-005
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