15,750 research outputs found
Film study for a star correlator Final report
Photographic recording film evaluation for star field image processing in spacecraft environment and use in star correlato
Maximum observable correlation for a bipartite quantum system
The maximum observable correlation between the two components of a bipartite
quantum system is a property of the joint density operator, and is achieved by
making particular measurements on the respective components. For pure states it
corresponds to making measurements diagonal in a corresponding Schmidt basis.
More generally, it is shown that the maximum correlation may be characterised
in terms of a `correlation basis' for the joint density operator, which defines
the corresponding (nondegenerate) optimal measurements. The maximum coincidence
rate for spin measurements on two-qubit systems is determined to be (1+s)/2,
where s is the spectral norm of the spin correlation matrix, and upper bounds
are obtained for n-valued measurements on general bipartite systems. It is
shown that the maximum coincidence rate is never greater than the computable
cross norm measure of entanglement, and a much tighter upper bound is
conjectured. Connections with optimal state discrimination and entanglement
bounds are briefly discussed.Comment: Revtex, no figure
Momentum transfer dependence of the proton's electric and magnetic polarizabilities
The Q^2-dependence of the sum of the electric and magnetic polarizabilities
of the proton is calculated over the range 0 \leq Q^2 \leq 6 GeV^2 using the
generalized Baldin sum rule. Employing a parametrization of the F_1 structure
function valid down to Q^2 = 0.06 GeV^2, the polarizabilities at the real
photon point are found by extrapolating the results of finite Q^2 to Q^2 = 0
GeV^2. We determine the evolution over four-momentum transfer to be consistent
with the Baldin sum rule using photoproduction data, obtaining \alpha + \beta =
13.7 \pm 0.7 \times 10^{-4}\, \text{fm}^3.Comment: 4 pages, 3 figure
Alien Registration- Hall, Thomas W. (Wade, Aroostook County)
https://digitalmaine.com/alien_docs/32561/thumbnail.jp
Quark-hadron duality constraints on \gamma Z box corrections to parity-violating elastic scattering
We examine the interference \gamma Z box corrections to parity-violating
elastic electron--proton scattering in the light of the recent observation of
quark-hadron duality in parity-violating deep-inelastic scattering from the
deuteron, and the approximate isospin independence of duality in the
electromagnetic nucleon structure functions down to Q^2 \approx 1 GeV^2.
Assuming that a similar behavior also holds for the \gamma Z proton structure
functions, we find that duality constrains the \gamma Z box correction to the
proton's weak charge to be \Re e\, \square_{\gamma Z}^V = (5.4 \pm 0.4) \times
10^{-3} at the kinematics of the Q_{\text{weak}} experiment. Within the same
model we also provide estimates of the \gamma Z corrections for future
parity-violating experiments, such as MOLLER at Jefferson Lab and MESA at
Mainz.Comment: 10 pages, 3 figures. Final version to be published in Phys. Lett.
Innovation, Managerial Effort, and Start-Up Performance
Managers of start-up firms make a number of important yet understudied decisions, such as whether or not to develop a new product, whether or not to choose a high-technology product or service, whether or not to use external assistance, and the amount of time and effort they will devote to their new company. These choices are informed by their access to various resources, such as the size of the management team, its education level, its previous experience working at start-ups, and other attributes. In this paper we consider how these resources influence optimal provision of effort, and examine decisions about innovative behavior (i.e., to market a novel or high-technology product) and managerial exertion (i.e., the hours per week spent by the managers and their decision to supplement their own efforts by employing external assistance such as consulting services)
Collaborative Educational Experiences through Higher Education-Industry Partnerships
This paper examines the perceptions of mentors and student interns from NASA's Langley Aerospace Research Summer Scholars (LARSS) program in Hampton, Virginia. Data for the current study are from student interns and mentors participating in the 2010, 10-week summer internship. Students are chosen from around the country based upon their applications and mentoring opportunities to participate in a summer program focusing on a range of specialty areas including: aeronautics; earth science research; exploration and flight; systems and concepts; systems engineering; subsonic/transonic testing; supersonic/hypersonic testing; and structures testing. This study presents information on mentors perceptions of academic preparedness brought to the workplace by student interns; student interns perceptions of how the internship helped develop key skill areas; and self-reports from student interns and their mentors about their internship experience
On topological phases of spin chains
Symmetry protected topological phases of one-dimensional spin systems have
been classified using group cohomology. In this paper, we revisit this problem
for general spin chains which are invariant under a continuous on-site symmetry
group G. We evaluate the relevant cohomology groups and find that the
topological phases are in one-to-one correspondence with the elements of the
fundamental group of G if G is compact, simple and connected and if no
additional symmetries are imposed. For spin chains with symmetry
PSU(N)=SU(N)/Z_N our analysis implies the existence of N distinct topological
phases. For symmetry groups of orthogonal, symplectic or exceptional type we
find up to four different phases. Our work suggests a natural generalization of
Haldane's conjecture beyond SU(2).Comment: 18 pages, 7 figures, 2 tables. Version v2 corresponds to the
published version. It includes minor revisions, additional references and an
application to cold atom system
Adolescent smoking networks: The effects of influence and selection on future smoking
Submitted in fulfillment of KU faculty's Open Access Policy.Peer influence and peer selection have both been linked to the smoking behavior of adolescents. The present investigation uses social network analysis methodology to explore the simultaneous effects of both processes on adolescent smoking and smoking susceptibility over two time periods. Results suggest the effects of friendship selection in 6th grade on smoking behavior in 7th grade were primarily direct. Selecting smokers as friends in 6th
grade predicted both smoking and smoking susceptibility in 7th grade, and selecting susceptibles predicted future friendship selection and peer influence. Influence processes were indirectly related to smoking. Smokers' influence
in 6th grade predicts the selection of smokers as friends in 7th grade. Smokers' influence also demonstrated a protective effect when ties were not reciprocated
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