11,427 research outputs found
A Hardy's Uncertainty Principle Lemma in Weak Commutation Relations of Heisenberg-Lie Algebra
In this article we consider linear operators satisfying a generalized
commutation relation of a type of the Heisenberg-Lie algebra. It is proven that
a generalized inequality of the Hardy's uncertainty principle lemma follows.
Its applications to time operators and abstract Dirac operators are also
investigated
Femtosecond laser nanostructuring of transparent materials: from bulk to fiber lasers
Progress in high power ultra-short pulse lasers has opened new frontiers in the physics of light-matter interactions and laser material processing. Recently there has been considerable interest in the application of femtosecond lasers to writing inside transparent materials and in particular to fabrication of three-dimensional microstructures
Upper limit to in scalar-tensor gravity theories
In a previous paper (Serna & Alimi 1996), we have pointed out the existence
of some particular scalar-tensor gravity theories able to relax the
nucleosynthesis constraint on the cosmic baryonic density. In this paper, we
present an exhaustive study of primordial nucleosynthesis in the framework of
such theories taking into account the currently adopted observational
constraints. We show that a wide class of them allows for a baryonic density
very close to that needed for the universe closure. This class of theories
converges soon enough towards General Relativity and, hence, is compatible with
all solar-system and binary pulsar gravitational tests. In other words, we show
that primordial nucleosynthesis does not always impose a very stringent bound
on the baryon contribution to the density parameter.Comment: uuencoded tar-file containing 16 pages, latex with 5 figures,
accepted for publication in Astrophysical Journal (Part 1
Nonperturbative infrared effects for light scalar fields in de Sitter space
We study the phi^4 scalar field theory in de Sitter space using the 2PI
effective action formalism. This formalism enables us to investigate the
nonperturbative quantum effects. We use the mean field and gap equations and
calculate the physical mass and effective potential. We find that
nonperturbative infrared effects on de Sitter space produce a curvature-induced
mass and work to restore the broken Z_2 symmetry.Comment: 14 pages, 3 figures, section 2 revised, discussion in section 4
changed, results not change
Phase reduction of stochastic limit cycle oscillators
We point out that the phase reduction of stochastic limit cycle oscillators
has been done incorrectly in the literature. We present a correct phase
reduction method for oscillators driven by weak external white Gaussian noises.
Numerical evidence demonstrates that the present phase equation properly
approximates the dynamics of the original full oscillator system.Comment: 4 pages, 2 figure
Occupation probability of harmonic-oscillator quanta for microscopic cluster-model wave functions
We present a new and simple method of calculating the occupation probability
of the number of total harmonic-oscillator quanta for a microscopic
cluster-model wave function. Examples of applications are given to the recent
calculations including -model for He, -model for
Li, and -model for Be as well as the classical
calculations of -model for Li and -model
for C. The analysis is found to be useful for quantifying the amount of
excitations across the major shell as well as the degree of clustering. The
origin of the antistretching effect is discussed.Comment: 9 page
The Experimental plan of the 4m Resonant Sideband Extraction Prototype for The LCGT
The 4m Resonant Sideband Extraction (RSE) interferometer is a planned prototype of the LCGT interferometer. The aim of the experiment is to operate a powerrecycled Broadband RSE interferometer with suspended optics and to achieve diagonalization of length signals of the central part of the interferometer directly through the optical setup. Details of the 4m RSE interferometer control method as well as the design of the experimental setup will be presented
Inelastic neutron scattering study on the resonance mode in an optimally doped superconductor LaFeAsOF
An optimally doped iron-based superconductor LaFeAsOF with
K has been studied by inelastic powder neutron scattering. The
magnetic excitation at \AA is enhanced below , leading to
a peak at meV as the resonance mode, in addition to the
formation of a gap at low energy below the crossover energy . The peak energy at \AA corresponds to in
good agreement with the other values of resonance mode observed in the various
iron-based superconductors, even in the high- cuprates. Although the
phonon density of states has a peak at the same energy as the resonance mode in
the present superconductor, the -dependence is consistent with the resonance
being of predominately magnetic origin.Comment: 4 pages, 5 Postscript figure
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