3,472 research outputs found
Coupling of Josephson current qubits using a connecting loop
We propose a coupling scheme for the three-Josephson junction qubits which
uses a connecting loop, but not mutual inductance. Present scheme offers the
advantages of a large and tunable level splitting in implementing the
controlled-NOT (CNOT) operation. We calculate the switching probabilities of
the coupled qubits in the CNOT operations and demonstrate that present CNOT
gate can meet the criteria for the fault-tolerant quantum computing. We obtain
the coupling strength as a function of the coupling energy of the Josephson
junction and the length of the connecting loop which varies with selecting two
qubits from the scalable design.Comment: 5 pages with updates, version to appear in Phys. Rev.
Higher-twist contributions to large pT hadron production in hadronic collisions
The scaling behavior of large-pT hadron production in hadronic collisions is
investigated. A significant deviation from the NLO QCD predictions is reported,
especially at high values of xT=2pT/sqrt(s). In contrast, the prompt photon and
jet production data prove in agreement with leading-twist expectations. These
results are interpreted as coming from a non-negligible contribution of
higher-twist processes, where the hadron is produced directly in the hard
subprocess. Predictions for scaling exponents at RHIC are successfully compared
to PHENIX preliminary measurements. We suggest to trigger on isolated large-pT
hadron production to enhance higher-twist processes, and point that the use of
isolated hadrons as a signal for new physics at colliders can be affected by
the presence of direct hadron production processes.Comment: 4 pages, 2 figures. Talk given at the 45th Rencontres de Moriond QCD
and High Energy Interactions, La Thuile, Italy, 13-20 March 201
Higher-Twist Dynamics in Large Transverse Momentum Hadron Production
A scaling law analysis of the world data on inclusive large-pT hadron
production in hadronic collisions is carried out. A significant deviation from
leading-twist perturbative QCD predictions at next-to-leading order is
reported. The observed discrepancy is largest at high values of xT=2pT/sqrt(s).
In contrast, the production of prompt photons and jets exhibits the scaling
behavior which is close to the conformal limit, in agreement with the
leading-twist expectation. These results bring evidence for a non-negligible
contribution of higher-twist processes in large-pT hadron production in
hadronic collisions, where the hadron is produced directly in the hard
subprocess rather than by gluon or quark jet fragmentation. Predictions for
scaling exponents at RHIC and LHC are given, and it is suggested to trigger the
isolated large-pT hadron production to enhance higher-twist processes.Comment: 5 pages, 4 figures. Extended introduction, additional reference
Effect of epitaxial strain on ferroelectric polarization in multiferroic BiFeO3 films
Multiferroic BiFeO3 epitaxial films with thickness ranging from 40 nm to 960
nm were grown by pulsed laser deposition on SrTiO3 (001) substrates with SrRuO3
bottom electrodes. X-ray characterization shows that the structure evolves from
angularly-distorted tetragonal with c/a ~ 1.04 to more bulk-like distorted
rhombohedral (c/a ~ 1.01) as the strain relaxes with increasing thickness.
Despite this significant structural evolution, the ferroelectric polarization
along the body diagonal of the distorted pseudo-cubic unit cells, as calculated
from measurements along the normal direction, barely changes.Comment: Legend in Fig.3 corrected and et
AN ANALYSIS OF LATIN AMERICAN PEANUT TRADE
The Latin American peanut industry is estimated using SUR. In scenarios, their demand is not affected dramatically by both price changes. The price changes affect the Latin American supply by roughly 15% and net trade by approximately 50%, compared to less than 10% in world price shock.peanut, SUR, scenarios, trade, International Relations/Trade,
An intuitive two-fluid picture of spontaneous 2D collisionless magnetic reconnection and whistler wave generation
An intuitive and physical two-fluid picture of spontaneous 2D collisionless magnetic reconnection and whistler wave generation is presented in the framework of 3D electron-magnetohydrodynamics. In this regime, canonical circulation (Q = m_e â Ă u + q_e B) flux tubes can be defined in analogy to magnetic flux tubes in ideal magnetohydrodynamics. Following the 3D behavior of these Q flux tubes provides a new perspective on collisionless reconnectionâa perspective that has been hard to perceive via examinations of 2D projections. This shows that even in a 2D geometry with an ignorable coordinate, a 3D examination is essential for a full comprehension of the process. Intuitive answers are given to three main questions in collisionless reconnection: why is reconnection spontaneous, why do particles accelerate extremely fast, and why are whistler waves generated? Possible extensions to other regimes are discussed
A generalized two-fluid picture of non-driven collisionless reconnection and its relation to whistler waves
A generalized, intuitive two-fluid picture of 2D non-driven collisionless magnetic reconnection is described using results from a full-3D numerical simulation. The relevant two-fluid equations simplify to the condition that the flux associated with canonical circulation Q=m_e â Ă u_e + q_e B is perfectly frozen into the electron fluid. In the reconnection geometry, flux tubes defined by Q are convected with the central electron current, effectively stretching the tubes and increasing the magnitude of Q exponentially. This, coupled with the fact that Q is a sum of two quantities, explains how the magnetic fields in the reconnection region reconnect and give rise to strong electron acceleration. The Q motion provides an interpretation for other phenomena as well, such as spiked central electron current filaments. The simulated reconnection rate was found to agree with a previous analytical calculation having the same geometry. Energy analysis shows that the magnetic energy is converted and propagated mainly in the form of the Poynting flux, and helicity analysis shows that the canonical helicity â«P·QâdV as a whole must be considered when analyzing reconnection. A mechanism for whistler wave generation and propagation is also described, with comparisons to recent spacecraft observations
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