53 research outputs found
Time development of a wave packet and the time delay
A one-dimensional scattering problem off a -shaped potential is
solved analytically and the time development of a wave packet is derived from
the time-dependent Schr\"odinger equation. The exact and explicit expression of
the scattered wave packet supplies us with interesting information about the
"time delay" by potential scattering in the asymptotic region. It is
demonstrated that a wave packet scattered by a spin-flipping potential can give
us quite a different value for the delay times from that obtained without
spin-degrees of freedom.Comment: 13 pages, plain TeX, 2 eps figures, tar+gzip+uuencode
Multiphoton Ionization as Time-Dependent Tunneling
A new semiclassical approach to ionization by an oscillating field is
presented. For a delta-function atom, an asymptotic analysis is performed with
respect to a quantity h, defined as the ratio of photon energy to ponderomotive
energy. This h appears formally equivalent to Planck's constant in a suitably
transformed Schroedinger equation and allows semiclassical methods to be
applicable. Systematically, a picture of tunneling wave packets in complex time
is developped, which by interference account for the typical ponderomotive
features of ionization curves. These analytical results are then compared to
numerical simulations and are shown to be in good agreement.Comment: 36 pages (also printable half size), uuencoded compressed tarred
Latex file with 9 Postscript figures included automaticall
Second-price auctions with private entry costs
We study asymmetric second-price auctions under incomplete information. The bidders have potentially different, commonly-known, valuations for the object and private information about their entry costs. The seller, however, does not benefit from these entry costs. We calculate the equilibrium strategies of the bidders and analyze the optimal design for the seller in this environment
Quantum Tunneling in the Wigner Representation
Time dependence for barrier penetration is considered in the phase space. An
asymptotic phase-space propagator for nonrelativistic scattering on a one -
dimensional barrier is constructed. The propagator has a form universal for
various initial state preparations and local potential barriers. It is
manifestly causal and includes time-lag effects and quantum spreading. Specific
features of quantum dynamics which disappear in the standard semi-classical
approximation are revealed. The propagator may be applied to calculation of the
final momentum and coordinate distributions, for particles transmitted through
or reflected from the potential barrier, as well as for elucidating the
tunneling time problem.Comment: 18 pages, LATEX, no figure
The Impact of Market Size and Users' Sophistication on Innovation: The Patterns of Demand and the Technology Life Cycle
Dues primeres pàgines de "Time-Dependent Tunneling Through Thin Barriers: A Simple Analytical Solution" by W. Elberfeld and M. Kebler
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