1,707 research outputs found
Gauged Fermionic Q-balls
We present a new model for a non-topological soliton (NTS) that contains
interacting fermions, scalar particles and a gauge field. Using a variational
approach, we estimate the energy of the localized configuration, showing that
it can be the lowest energy state of the system for a wide range of parameters.Comment: 5 pages, 2 figures; revised version to appear in Phys. Rev.
The ground state energy of the weakly interacting Bose gas at high density
We prove the Lee-Huang-Yang formula for the ground state energy of the 3D
Bose gas with repulsive interactions described by the exponential function, in
a simultaneous limit of weak coupling and high density. In particular, we show
that the Bogoliubov approximation is exact in an appropriate parameter regime,
as far as the ground state energy is concerned.Comment: RevTeX4, 16 page
Fully submerged composite cryogenic testing
New methods for marine salvage and decommissioning of structures in the open sea are continually being sought in order to improve control and lower operational costs [1]. The concept design of a lightweight, cryogenic, marine, heavy lift, buoyancy system has been investigated [2]. The objective is to be able to raise or lower high mass objects controlled solely from a surface support vessel. The overall design concept and associated system development issues have been discussed previously. A number of the sub-systems in one complete buoyancy system involve considerable design and development, these include: structural design of the buoyancy chamber, mechanical systems to control and connection to the lift device, the cryogenic system itself and overall process control systems. The main area of concern in the design process is the composite cryogenic Dewar. This is required to operate not only at temperatures as low as -196oC but also to withstand pressure differences exceeding 35bar. As such the composite materials have to perform in a very aggressive environment. This work details a method for fully submersed composite cryogenic testing in order to qualify the materials for use in the Dewar of the buoyancy system
Jarlskog Invariant of the Neutrino Mapping Matrix
The Jarlskog Invariant of the neutrino mapping matrix is
calculated based on a phenomenological model which relates the smallness of
light lepton masses and (of ) with the smallness of
violation. For small violating phase in the lepton sector,
is proportional to , but and are proportional
to . This leads to . Assuming
, we find
, consistent with the present experimental
data.Comment: 19 page
Non-topological solitons in brane world models
We examine some general properties of a certain class of scalar filed theory
models containing non-topological soliton solutions in the context of brane
world models with compact large extra dimensions. If a scalar field is allowed
to propagate in extra space, then, beside standard Kaluza-Klein type
excitations, a whole new class of very massive soliton-type states can exist.
Depending on their abundance, they can be important dark matter candidates or
give significant contribution to entropy and energy density in our universe. .Comment: version accepted for publication in Physical Review
Renormalization Effects in a Dilute Bose Gas
The low-density expansion for a homogeneous interacting Bose gas at zero
temperature can be formulated as an expansion in powers of ,
where is the number density and is the S-wave scattering length.
Logarithms of appear in the coefficients of the expansion. We show
that these logarithms are determined by the renormalization properties of the
effective field theory that describes the scattering of atoms at zero density.
The leading logarithm is determined by the renormalization of the pointlike scattering amplitude.Comment: 10 pages, 1 postscript figure, LaTe
Convergent Iterative Solutions of Schroedinger Equation for a Generalized Double Well Potential
We present an explicit convergent iterative solution for the lowest energy
state of the Schroedinger equation with a generalized double well potential
. The condition for the convergence of the
iteration procedure and the dependence of the shape of the groundstate wave
function on the parameter are discussed.Comment: 23 pages, 7 figure
High sensitivity analysis of phenylthiohydantoin amino acid derivatives by electrospray mass spectrometry
A new methodology has been developed for high sensitivity electrospray ionization mass spectrometric analyses of phenylthiohydantoin (PTH) amino acid derivatives. Key components of the methodology are the use of a solvent system consisting of methanol/dichloromethane (1:1 v/v) containing 5-mM lithium triflate, a stainless steel electrode having a relatively large surface area, and a microscale electrospray nozzle that provides for stable electrospray at flow rates in the range of 100–500 nL/min. A linear response for the absolute signal intensity of the protonated molecule was observed for a number of derivatives over the concentration range of 50–1000 fmol/μL. For all except the arginine derivative, there was a decrease in the signal intensity with increasing flow rate with 100–300 nL/min being optimum. Collision induced dissociation (CID) product ion spectra were obtained for 21 derivatives including carboxymethyl cysteine and dehydrothreonine. Leucine and isoleucine can be distinquished on the basis of their CID product ion spectra. A subfemtomole detection limit was demonstrated for the phenylalanine PTH derivative in a selected reaction monitoring (SRM) experiment. Samples from an automated Edman microsequencer run have been analyzed using the new technique and compared to results obtained by conventional high-performance liquid chromatography analysis with UV detection. This work demonstrates the feasibility of using mass spectrometry to identify and quantitate the products generated by automated protein microsequencing using standard Edman degradation chemistry
A Generalized Circle Theorem on Zeros of Partition Function at Asymmetric First Order Transitions
We present a generalized circle theorem which includes the Lee-Yang theorem
for symmetric transitions as a special case. It is found that zeros of the
partition function can be written in terms of discontinuities in the
derivatives of the free energy. For asymmetric transitions, the locus of the
zeros is tangent to the unit circle at the positive real axis in the
thermodynamic limit. For finite-size systems, they lie off the unit circle if
the partition functions of the two phases are added up with unequal prefactors.
This conclusion is substantiated by explicit calculation of zeros of the
partition function for the Blume-Capel model near and at the triple line at low
temperatures.Comment: 10 pages, RevTeX. To be published in PRL. 3 Figures will be sent upon
reques
Exact Zeros of the Partition Function for a Continuum System with Double Gaussian Peaks
We calculate the exact zeros of the partition function for a continuum system
where the probability distribution for the order parameter is given by two
asymmetric Gaussian peaks. When the positions of the two peaks coincide, the
two separate loci of zeros which used to give first-order transition touch each
other, with density of zeros vanishing at the contact point on the positive
real axis. Instead of the second-order transition of Ehrenfast classification
as one might naively expect, one finds a critical behavior in this limit.Comment: 13 pages, 6 figures, revtex, minor changes in fig.2, to be published
in Physical Review
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