22,192 research outputs found
Measurements of the Influence of Acceleration and Temperature of Bodies on their Weight
A brief review of experimental research of the influence of acceleration and
temperatures of test mass upon gravitation force, executed between the 1990s
and the beginning of 2000 is provided.Results of weighing a rotor of a
mechanical gyroscope with a horizontal axis, an anisotropic crystal with the
big difference of the speed of longitudinal acoustic waves, measurements of
temperature dependence of weight of metal bars of non-magnetic materials, and
also measurement of restitution coefficients at quasi-elastic impact of a steel
ball about a massive plate are given. A negative temperature dependence of the
weight of a brass core was measured. All observably experimental effects, have
probably a general physical reason connected with the weight change dependent
upon acceleration of a body or at thermal movement of its microparticles.Comment: 7 pages, 6 figures. Presented at the 5-th Symposium on New Frontiers
and Future Concepts (STAIF-2008
Spectral theory of soliton and breather gases for the focusing nonlinear Schrödinger equation
Solitons and breathers are localized solutions of integrable systems that can be viewed as “particles” of complex statistical objects called soliton and breather gases. In view of the growing evidence of their ubiquity in fluids and nonlinear optical media, these “integrable” gases present a fundamental interest for nonlinear physics. We develop an analytical theory of breather and soliton gases by considering a special, thermodynamic-type limit of the wave-number–frequency relations for multiphase (finite-gap) solutions of the focusing nonlinear Schrödinger equation. This limit is defined by the locus and the critical scaling of the band spectrum of the associated Zakharov-Shabat operator, and it yields the nonlinear dispersion relations for a spatially homogeneous breather or soliton gas, depending on the presence or absence of the “background” Stokes mode. The key quantity of interest is the density of states defining, in principle, all spectral and statistical properties of a soliton (breather) gas. The balance of terms in the nonlinear dispersion relations determines the nature of the gas: from an ideal gas of well separated, noninteracting breathers (solitons) to a special limiting state, which we term a breather (soliton) condensate, and whose properties are entirely determined by the pairwise interactions between breathers (solitons). For a nonhomogeneous breather gas, we derive a full set of kinetic equations describing the slow evolution of the density of states and of its carrier wave counterpart. The kinetic equation for soliton gas is recovered by collapsing the Stokes spectral band. A number of concrete examples of breather and soliton gases are considered, demonstrating the efficacy of the developed general theory with broad implications for nonlinear optics, superfluids, and oceanography. In particular, our work provides the theoretical underpinning for the recently observed remarkable connection of the soliton gas dynamics with the long-term evolution of spontaneous modulational instability
Cyclicity in weighted Bergman type spaces
We use the so called resolvent transform method to study the cyclicity of the
one point mass singular inner function in weighted Bergman type spaces.Comment: 20 page
A Process for Producing Ice Coverage Marine Information Objects (MIOs) in IHO S-57 Format
While global warming may be opening up more Arctic waters in the summer, ice still infests key shipping lanes in the northern hemisphere during the winter months. To safely navigate these areas, mariners rely on daily ice coverage charts produced by national governmental agencies. Ice charts are primarily issued in paper format or as a fax. However, there is increased interest to ice coverage information on vessel navigation systems such as an Electronic Chart and Display Information Systems (ECDIS). However, to do so, the ice information must be provided as a separate layer of information to the Electronic Navigational Chart (ENC)
Clock transition by continuous dynamical decoupling of a three-level system
We present a novel continuous dynamical decoupling scheme for the
construction of a robust qubit in a three-level system. By means of a clock
transition adjustment, we first show how robustness to environmental noise is
achieved, while eliminating drive-noise, to first-order. We demonstrate this
scheme with the spin sub-levels of the NV-centre's electronic ground state. By
applying drive fields with moderate Rabi frequencies, the drive noise is
eliminated and an improvement of 2 orders of magnitude in the coherence time is
obtained compared to the pure dephasing time. We then show how the clock
transition adjustment can be tuned to eliminate also the second-order effect of
the environmental noise with moderate drive fields. A further improvement of
more than 1 order of magnitude in the coherence time is expected and confirmed
by simulations. Hence, our scheme prolongs the coherence time towards the
lifetime-limit using a relatively simple experimental setup.Comment: 7 pages, 5 figure
Quarkonium Spectral Function from Anisotropic Lattice
We discuss the behavior of charmonia and bottomonia correlators and spectral
functions above the deconfinement temperature and determine melting
temperatures for different mesonic states.Comment: 4 pages, 6 figures. Talk presented at Hard Probes 2006, Asilomar,
California, USA, June 9-16, 200
Unified Approach to KdV Modulations
We develop a unified approach to integrating the Whitham modulation
equations. Our approach is based on the formulation of the initial value
problem for the zero dispersion KdV as the steepest descent for the scalar
Riemann-Hilbert problem, developed by Deift, Venakides, and Zhou, 1997, and on
the method of generating differentials for the KdV-Whitham hierarchy proposed
by El, 1996. By assuming the hyperbolicity of the zero-dispersion limit for the
KdV with general initial data, we bypass the inverse scattering transform and
produce the symmetric system of algebraic equations describing motion of the
modulation parameters plus the system of inequalities determining the number
the oscillating phases at any fixed point on the - plane. The resulting
system effectively solves the zero dispersion KdV with an arbitrary initial
data.Comment: 27 pages, Latex, 5 Postscript figures, to be submitted to Comm. Pure.
Appl. Mat
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