106,964 research outputs found

### Cosmic Strings, Zero Modes and SUSY breaking in Nonabelian N=1 Gauge Theories

We investigate the microphysics of cosmic strings in Nonabelian gauge
theories with N=1 supersymmetry. We give the vortex solutions in a specific
example and demonstrate that fermionic superconductivity arises because of the
couplings and interactions dictated by supersymmetry. We then use supersymmetry
transformations to obtain the relevant fermionic zero modes and investigate the
role of soft supersymmetry breaking on the existence and properties of the
superconducting strings.Comment: 12 pages, RevTex, submitted to Phys. Rev.

### Integrity bases for local invariants of composite quantum systems

Unitary group branchings appropriate to the calculation of local invariants
of density matrices of composite quantum systems are formulated using the
method of $S$-function plethysms. From this, the generating function for the
number of invariants at each degree in the density matrix can be computed. For
the case of two two-level systems the generating function is $F(q) = 1 + q +
4q^{2} + 6 q^{3} + 16 q^{4} + 23 q^{5} + 52 q^{6} + 77 q^{7} + 150 q^{8} + 224
q^{9} + 396 q^{10} + 583 q^{11}+ O(q^{12})$. Factorisation of such series leads
in principle to the identification of an integrity basis of algebraically
independent invariants. This note replaces Appendix B of our paper\cite{us} J
Phys {\bf A33} (2000) 1895-1914 (\texttt{quant-ph/0001076}) which is incorrect.Comment: Latex, 4 pages, correcting Appendix B of quant-ph/0001076 Error in
$F(q)$ corrected and conclusions modified accordingl

### Multibody Interplanetary Swingby Trajectories /MIST-1/

Computer program incorporates new isolation procedure to determine interplanetary trajectories which utilize a maximum of three flybys. Program also computes singe planet flybys and direct transfer trajectories. The three principle systems employed in MIST-1 use as their fundamental plane the mean plane of the earth's orbit around the sun

### Chiral Vortons and Cosmological Constraints on Particle Physics

We investigate the cosmological consequences of particle physics theories
that admit stable loops of current-carrying string - vortons. In particular, we
consider chiral theories where a single fermion zero mode is excited in the
string core, such as those arising in supersymmetric theories with a D-term.
The resulting vortons formed in such theories are expected to be more stable
than their non-chiral cousins. General symmetry breaking schemes are considered
in which strings formed at one symmetry breaking scale become current-carrying
at a subsequent phase transition. The vorton abundance is estimated and
constraints placed on the underlying particle physics theories from
cosmological observations. Our constraints on the chiral theory are
considerably more stringent than the previous estimates for more general
theories.Comment: minor corrections made. This version will appear in PR

### Daze fasteners

A daze fastener system for connecting two or more structural elements wherein the structural elements and fastener parts have substantially different coefficient of thermal expansion physical property characteristics is employed in this invention. By providing frusto-conical abutting surfaces between the structural elements and fastener parts any differences in thermal expansion/contraction between the parts is translated to sliding motion and avoids deleterious thermal stresses in the connection. An essential feature for isotropic homogeneous material connections is that at least two sets of mating surfaces are required wherein each set of mating surfaces have line element extensions that pass through a common point

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### Consumer confidence indeces and short-term forecasting of consumption

Recently there has been growing interest in examining the potential shortterm
link between survey-based confidence indicators and real economic activity,
notably for macroeconomic policy making. This paper builds on previous studies to
establish whether there is a short-term predictive relationship between measures of
consumer confidence and actual consumption, that could be used for forecasting, in a
range of major industrial countries. It then extends such previous analyses by
assessing whether this relation has changed over time, and whether we can attribute
any time-varying relation to structural developments in the economy, such as financial
deepening and the increasing role of house prices in determination of consumption

### Explicit solution of an inverse first-passage time problem for L\'{e}vy processes and counterparty credit risk

For a given Markov process $X$ and survival function $\overline{H}$ on
$\mathbb{R}^+$, the inverse first-passage time problem (IFPT) is to find a
barrier function $b:\mathbb{R}^+\to[-\infty,+\infty]$ such that the survival
function of the first-passage time $\tau_b=\inf \{t\ge0:X(t)<b(t)\}$ is given
by $\overline{H}$. In this paper, we consider a version of the IFPT problem
where the barrier is fixed at zero and the problem is to find an initial
distribution $\mu$ and a time-change $I$ such that for the time-changed process
$X\circ I$ the IFPT problem is solved by a constant barrier at the level zero.
For any L\'{e}vy process $X$ satisfying an exponential moment condition, we
derive the solution of this problem in terms of $\lambda$-invariant
distributions of the process $X$ killed at the epoch of first entrance into the
negative half-axis. We provide an explicit characterization of such
distributions, which is a result of independent interest. For a given
multi-variate survival function $\overline{H}$ of generalized frailty type, we
construct subsequently an explicit solution to the corresponding IFPT with the
barrier level fixed at zero. We apply these results to the valuation of
financial contracts that are subject to counterparty credit risk.Comment: Published at http://dx.doi.org/10.1214/14-AAP1051 in the Annals of
Applied Probability (http://www.imstat.org/aap/) by the Institute of
Mathematical Statistics (http://www.imstat.org

### Umbilical disconnect actuator

Contamination of sensitive equipment when squibs are fired is prevented by O-rings which retain the debris of squib discharge within the disconnect device

### Consumer confidence indices and short-term forecasting of consumption

Recently there has been growing interest in examining the potential shortterm link between survey-based confidence indicators and real economic activity, notably for macroeconomic policy making. This paper builds on previous studies to establish whether there is a short-term predictive relationship between measures of consumer confidence and actual consumption, that could be used for forecasting, in a range of major industrial countries. It then extends such previous analyses by assessing whether this relation has changed over time, and whether we can attribute any time-varying relation to structural developments in the economy, such as financial deepening and the increasing role of house prices in determination of consumption

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