492 research outputs found
Rigidity around Poisson Submanifolds
We prove a rigidity theorem in Poisson geometry around compact Poisson
submanifolds, using the Nash-Moser fast convergence method. In the case of
one-point submanifolds (fixed points), this immediately implies a stronger
version of Conn's linearization theorem, also proving that Conn's theorem is,
indeed, just a manifestation of a rigidity phenomenon; similarly, in the case
of arbitrary symplectic leaves, it gives a stronger version of the local normal
form theorem; another interesting case corresponds to spheres inside duals of
compact semisimple Lie algebras, our result can be used to fully compute the
resulting Poisson moduli space.Comment: 43 pages, v3: published versio
Molecular vibration in cold collision theory
Cold collisions of ground state oxygen molecules with Helium have been
investigated in a wide range of cold collision energies (from 1 K up to 10
K) treating the oxygen molecule first as a rigid rotor and then introducing the
vibrational degree of freedom. The comparison between the two models shows that
at low energies the rigid rotor approximation is very accurate and able to
describe all the dynamical features of the system. The comparison between the
two models has also been extended to cases where the interaction potential He -
O is made artificially stronger. In this case vibration can perturb rate
constants, but fine-tuning the rigid rotor potential can alleviate the
discrepancies between the two models.Comment: 11 pages, 3 figure
Using Nonlinear Response to Estimate the Strength of an Elastic Network
Disordered networks of fragile elastic elements have been proposed as a model
of inner porous regions of large bones [Gunaratne et.al., cond-mat/0009221,
http://xyz.lanl.gov]. It is shown that the ratio of responses of such
a network to static and periodic strain can be used to estimate its ultimate
(or breaking) stress. Since bone fracture in older adults results from the
weakening of porous bone, we discuss the possibility of using as a
non-invasive diagnostic of osteoporotic bone.Comment: 4 pages, 4 figure
On non-local variational problems with lack of compactness related to non-linear optics
We give a simple proof of existence of solutions of the dispersion manage-
ment and diffraction management equations for zero average dispersion,
respectively diffraction. These solutions are found as maximizers of non-linear
and non-local vari- ational problems which are invariant under a large
non-compact group. Our proof of existence of maximizer is rather direct and
avoids the use of Lions' concentration compactness argument or Ekeland's
variational principle.Comment: 30 page
Quantum Computing of Quantum Chaos in the Kicked Rotator Model
We investigate a quantum algorithm which simulates efficiently the quantum
kicked rotator model, a system which displays rich physical properties, and
enables to study problems of quantum chaos, atomic physics and localization of
electrons in solids. The effects of errors in gate operations are tested on
this algorithm in numerical simulations with up to 20 qubits. In this way
various physical quantities are investigated. Some of them, such as second
moment of probability distribution and tunneling transitions through invariant
curves are shown to be particularly sensitive to errors. However,
investigations of the fidelity and Wigner and Husimi distributions show that
these physical quantities are robust in presence of imperfections. This implies
that the algorithm can simulate the dynamics of quantum chaos in presence of a
moderate amount of noise.Comment: research at Quantware MIPS Center http://www.quantware.ups-tlse.fr,
revtex 11 pages, 13 figs, 2 figs and discussion adde
Marketing madness or financial folly?: Implementing equity crowdfunding in the record industry
Purpose The purpose of this paper is to explore the implementation of equity crowdfunding (ECF) within the record industry in terms of challenges and opportunities, in addition to the marketing and financial implications for independent music artists and major record labels. Design/methodology/approach This study adopted a qualitative methodology consisting of two-stage interview-based research methods. A total of 44 semi-structured in-depth interviews were conducted with the CEOs of ECF platforms in the record industry, other related record industry informants, independent artist managers and senior executives from major record labels. Findings The loyalty aspect of ECF may have significant marketing potential in terms of inconspicuously using the equity platform as a âprosumerâ identification mechanism. As this early career stage of artists is delicate in terms of establishing trust and patronage from their fans, these early marketing and ECF ventures should be implemented directly from the artist without external third-party involvement. Research limitations/implications The implications of this paperâs findings and theoretical model are not limited to the two studied stakeholder groups of the record industry. The insights in relation to the obstinate lack of understanding and clarity (particularly for independent artists) which surround ECF are likely to influence short-term strategic approaches by other players throughout the wider music industry. Practical implications The insights regarding negative approaches towards ECF by the labels may influence future âcoopetition strategiesâ for independent labels, as they seek to navigate the changing industry dynamics. Originality/value This paper is the first study to empirically explore the predominantly under-researched area of ECF implementation in the record industry in terms of marketing and financial consequences for artists and labels. </jats:sec
decays into and mesons
We consider the nonleptonic and semileptonic decays of -mesons into
and mesons. QCD sum rules are used to calculate the form
factors associated with these decays, and the correspondig decay rates. On the
basis of data on , which goes dominantly via the
transition , we conclude that there is space for a
sizeable light quark component on .Comment: 14 pages, RevTeX4 including 5 figures in ps file
Tunneling of quantum rotobreathers
We analyze the quantum properties of a system consisting of two nonlinearly
coupled pendula. This non-integrable system exhibits two different symmetries:
a permutational symmetry (permutation of the pendula) and another one related
to the reversal of the total momentum of the system. Each of these symmetries
is responsible for the existence of two kinds of quasi-degenerated states. At
sufficiently high energy, pairs of symmetry-related states glue together to
form quadruplets. We show that, starting from the anti-continuous limit,
particular quadruplets allow us to construct quantum states whose properties
are very similar to those of classical rotobreathers. By diagonalizing
numerically the quantum Hamiltonian, we investigate their properties and show
that such states are able to store the main part of the total energy on one of
the pendula. Contrary to the classical situation, the coupling between pendula
necessarily introduces a periodic exchange of energy between them with a
frequency which is proportional to the energy splitting between
quasi-degenerated states related to the permutation symmetry. This splitting
may remain very small as the coupling strength increases and is a decreasing
function of the pair energy. The energy may be therefore stored in one pendulum
during a time period very long as compared to the inverse of the internal
rotobreather frequency.Comment: 20 pages, 11 figures, REVTeX4 styl
Tests for a Strong Electroweak Sector at Future e^+e^- High Energy Colliders
The study of the scattering at high energy of the gauge bosons W and Z, in
particular longitudinally polarized W and Z, can clarify the mechanism of
spontaneous symmetry breaking in the Standard Model of the electroweak
interactions. Different models of strong electroweak sector, based on the
effective lagrangian approach are briefly reviewed. They include models with no
resonance, with scalar resonance, additional vector and axial-vector
resonances. The effective Lagrangians are derived from the chiral symmetry of
the symmetry breaking sector. Limits on these models from existing
measurements, mainly LEP and Tevatron, are considered. We study also direct and
indirect effects of the new interactions at high energy future e^+e^- linear
colliders, through WW scattering and the direct production of these new vector
gauge bosons.Comment: 74 pages, 19 figures and 4 tables included, Latex, uses epsf, to
appear in La Rivista del Nuovo Cimento, some minor change
Observation of exclusive DVCS in polarized electron beam asymmetry measurements
We report the first results of the beam spin asymmetry measured in the
reaction e + p -> e + p + gamma at a beam energy of 4.25 GeV. A large asymmetry
with a sin(phi) modulation is observed, as predicted for the interference term
of Deeply Virtual Compton Scattering and the Bethe-Heitler process. The
amplitude of this modulation is alpha = 0.202 +/- 0.028. In leading-order and
leading-twist pQCD, the alpha is directly proportional to the imaginary part of
the DVCS amplitude.Comment: 6 pages, 5 figure
- âŠ