49,329 research outputs found
Gravitomagnetic Field and Time-Dependent Spin-Rotation Coupling
The Kerr metric of spherically symmetric gravitational field is analyzed
through the coordinate transformation from the rotating frame to fixing frame,
and consequently that the inertial force field (with the exception of the
centrifugal force field) in the rotating system is one part of its
gravitomagnetic field is verified. We investigate the spin-rotation coupling
and, by making use of Lewis-Riesenfeld invariant theory, we obtain exact
solutions of the Schr\"{o}dinger equation of a spinning particle in a
time-dependent rotating reference frame. A potential application of these exact
solutions to the investigation of Earths rotating frequency fluctuation
by means of neutron-gravity interferometry experiment is briefly discussed in
the present paper.Comment: 6 pages, 0 figures, Late
Anomalous Higgs-top Coupling Pollution on Triple Higgs Coupling Extraction at Future High-Luminosity Electron-Positron Collider
One of the most challenging tasks for future high-luminosity
electron-positron colliders is to extract Higgs triple coupling. It was
proposed that this can be carried out via the precisely measuring the cross
section of ZH associated production up to . In this paper, we example
the possible heavy pollution from Higgs-top anomalous coupling. Our numerical
results show that the pollution is small for .
However for the higher energy collider, pollution is sizable, which should be
taken into account. We further explored the possibility to measure CP-violated
Higgs top coupling, via the forward-backward asymmetry for the process
. The asymmetry can reach which is comparable to
the precision of cross section measurement.Comment: 10 pages, 6 figures, discussions and references added, published in
Phys. Rev.
Parton recombination effect in polarized parton distributions
Parton recombination corrections to the standard spin-dependent
Altarelli-Parisi evolution equation are considered in a nonlinear evolution
equation. The properties of this recombination equation and its relation with
the spin-averaged form are discussed.Comment: 25 pages, 1 figure, to be published in Nucl. Phys. B. Appendix is
correcte
Reimagining career guidance: towards a pluralistic perspective
Difficulties concerning the identified mis-match between supply and demand sides of the labour market are discussed. The variability of career guidance services for young people across Europe is illustrated together with policy initiatives in some cases leading to problems of professional identity and limited support to clients of the service. The risks associated with a monoculture of ‘one size fits all’ approach to guidance practice are discussed. The principles of pluralistic approaches to counselling are discussed with the suggestion that this might prove to be a fertile way forward for career guidance practice
Improved speed estimation in sensorless PM brushless AC drives
The application of flux-observer-based sensorless control to permanent-magnet brushless AC motor drives is described. Current methods of speed estimation are assessed, both theoretically and experimentally, and an improved method, which combines the best features of methods in which speed is derived from the differential of rotor position and from the ratio of the electromotive force to excitation flux linkage, is proposed. Its performance is verified experimentally
The chaotic effects in a nonlinear QCD evolution equation
The corrections of gluon fusion to the DGLAP and BFKL equations are discussed
in a united partonic framework. The resulting nonlinear evolution equations are
the well-known GLR-MQ-ZRS equation and a new evolution equation. Using the
available saturation models as input, we find that the new evolution equation
has the chaos solution with positive Lyaponov exponents in the perturbative
range. We predict a new kind of shadowing caused by chaos, which blocks the QCD
evolution in a critical small range. The blocking effect in the evolution
equation may explain the Abelian gluon assumption and even influence our
expectations to the projected Large Hadron Electron Collider (LHeC), Very Large
Hadron Collider (VLHC) and the upgrade (CppC) in a circular collider
(SppC).Comment: 58 pages, 23 figures,. Final version to appear in NP
Exact solutions to the time-dependent supersymmetric muliphoton Jaynes-Cummings model and the Chiao-Wu model
By using both the Lewis-Riesenfeld invariant theory and the invariant-related
unitary transformation formulation, the present paper obtains the exact
solutions to the time-dependent supersymmetric two-level multiphoton
Jaynes-Cummings model and the Chiao-Wu model that describes the propagation of
a photon inside the optical fiber. On the basis of the fact that the two-level
multiphoton Jaynes-Cummings model possesses the supersymmetric structure, an
invariant is constructed in terms of the supersymmetric generators by working
in the sub-Hilbert-space corresponding to a particular eigenvalue of the
conserved supersymmetric generators (i.e., the time-independent invariant). By
constructing the effective Hamiltonian that describes the interaction of the
photon with the medium of the optical fiber, it is further verified that the
particular solution to the Schr\"{o}dinger equation is the eigenfunction of the
second-quantized momentum operator of photons field. This, therefore, means
that the explicit expression (rather than the hidden form that involves the
chronological product) for the time-evolution operator of wave function is
obtained by means of the invariant theories.Comment: 14 pages, Latex. This is a revised version of the published paper:
Shen J Q, Zhu H Y 2003 Ann. Phys.(Leipzig) Vol.12 p.131-14
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