513 research outputs found
Julia Lawrence to Susan Ursin Niemcewicz, December 24, 1819
Julia Lawrence wrote from Jamaica to Susan Ursin Niemcewicz, her aunt, addressed to Elizabethtown, NJ. She talks about Jamaica and the enslaved people there are allowed three days off to celebrate around Christmas, that is all the time the have off during the year. She remarks that they should do everything in their power to contribute to their happiness. She also talks about family and how she and her husband were both recently sick.
People Included: John Kean (JK1814), Julia Ursin Niemcewicz Kean, Peter Philip James Kean, Sarah Sabina Morris Kean, Philip Livingston, John Tharp Lawrence, John Thraphttps://digitalcommons.kean.edu/lhc_1810s/1021/thumbnail.jp
On a coordinate independent description of string worldsheet theory
We study worldsheet conformal invariance for bosonic string propagating in a
curved background using the hamiltonian formalism. In order to formulate the
problem in a background independent manner we first rewrite the worldsheet
theory in a language where it describes a single particle moving in an
infinite-dimensional curved spacetime. This language is developed at a formal
level without regularizing the infinite-dimensional traces. Then we adopt
DeWitt's (Phys.Rev.85:653-661,1952) coordinate independent formulation of
quantum mechanics in the present context. Given the expressions for the
classical Virasoro generators, this procedure enables us to define the
coordinate invariant quantum analogues which we call DeWitt-Virasoro
generators. This framework also enables us to calculate the invariant matrix
elements of an arbitrary operator constructed out of the DeWitt-Virasoro
generators between two arbitrary scalar states. Using these tools we further
calculate the DeWitt-Virasoro algebra in spin-zero representation. The result
is given by the Witt algebra with additional anomalous terms that vanish for
Ricci-flat backgrounds. Further analysis need to be performed in order to
precisely relate this with the beta function computation of Friedan and others.
Finally, we explain how this analysis improves the understanding of showing
conformal invariance for certain pp-wave that has been recently discussed using
hamiltonian framework.Comment: 32 pages, some reorganization for more elaborate explanation, no
change in conclusio
Mutually unbiased binary observable sets on N qubits
The Pauli operators (tensor products of Pauli matrices) provide a complete
basis of operators on the Hilbert space of N qubits. We prove that the set of
4^N-1 Pauli operators may be partitioned into 2^N+1 distinct subsets, each
consisting of 2^N-1 internally commuting observables. Furthermore, each such
partitioning defines a unique choice of 2^N+1 mutually unbiased basis sets in
the N-qubit Hilbert space. Examples for 2 and 3 qubit systems are discussed
with emphasis on the nature and amount of entanglement that occurs within these
basis sets.Comment: 5 pages, 5 figures. Replacement - expanded introduction and
conclusions; added reference
The inverse moment problem for convex polytopes
The goal of this paper is to present a general and novel approach for the
reconstruction of any convex d-dimensional polytope P, from knowledge of its
moments. In particular, we show that the vertices of an N-vertex polytope in
R^d can be reconstructed from the knowledge of O(DN) axial moments (w.r.t. to
an unknown polynomial measure od degree D) in d+1 distinct generic directions.
Our approach is based on the collection of moment formulas due to Brion,
Lawrence, Khovanskii-Pukhikov, and Barvinok that arise in the discrete geometry
of polytopes, and what variously known as Prony's method, or Vandermonde
factorization of finite rank Hankel matrices.Comment: LaTeX2e, 24 pages including 1 appendi
Natural Theories of Ultra-Low Mass PNGB's: Axions and Quintessence
We consider the Wilson Line PNGB which arises in a U(1)^N gauge theory,
abstracted from a latticized, periodically compactified extra dimension U(1).
Planck scale breaking of the PNGB's global symmetry is suppressed, providing
natural candidates for the axion and quintessence. We construct an explicit
model in which the axion may be viewed as the 5th component of the U(1)_Y gauge
field in a 1+4 latticized periodically compactified extra dimension. We also
construct a quintessence PNGB model where the ultra-low mass arises from
Planck-scale suppressed physics itself.Comment: 20 pages, fixed typo and reference
Group Process and Organizational Environment: Student Organizations in the University
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68768/2/10.1177_089976407400300305.pd
Mental Health Changes Over Time: a Longitudinal Perspective: Summary Report: Mental Health and Wellbeing Transition Study
Bryant, R., Lawrence-Wood, E., Baur, J., McFarlane, A., Hodson, S., Sadler, N., Benassi, H., Howell, S., Abraham, M., Iannos, M., Hansen, C., Searle, A., Van Hooff, M
Mental Health Changes Over Time: a Longitudinal Perspective: Mental Health and Wellbeing Transition Study
Bryant, R., Lawrence-Wood, E., Baur, J., McFarlane, A., Hodson, S., Sadler, N., Benassi, H., Howell, S., Abraham, M., Iannos, M., Hansen, C., Searle, A., Van Hooff, M
Black Hole, Jet, and Disk: The Universal Engine
In this paper I review the results of our ongoing project to investigate the
coupling between accretion disk and radio jet in galactic nuclei and stellar
mass black holes. We find a good correlation between the UV bump luminosity and
the radio luminosities of AGN, which improves upon the usual [OIII]/radio
correlations. Taking mass and energy conservation in the jet/disk system into
account we can successfully model the correlation for radio-loud and radio-weak
quasars. We find that jets are comparable in power to the accretion disk
luminosity, and the difference between radio-loud and radio-weak may correspond
to two natural stages of the relativistic electron distribution -- assuming
that radio weak quasars have jets as well. The distribution of flat- and
steep-spectrum sources is explained by bulk Lorentz factors gamma_j ~ 5-10. The
absence of radio-loud quasars below a critical optical luminosity coincides
with the FR I/FR II break and could be explained by a powerdependent,
``closing'' torus. This points towards a different type of obscuring torus in
radio-loud host galaxies which might be a consequence of past mergers (e.g. by
the temporary formation of a binary black-hole). Interaction of the jet with
the closing torus might in principle also help to make a jet radio-loud.
Turning to stellar-mass black holes we find that galactic jet sources can be
described with the same coupled jet/disk model as AGN which is suggestive of
some kind of universal coupling between jet and accretion disk around compact
objects.Comment: to appear in ``Jets from Stars and Galactic Nuclei'', Springer
Lecture Notes, plain TeX, 16 pages, also at
http://www.astro.umd.edu/~hfalcke/publications.htm
A Kinematically Complete Measurement of the Proton Structure Function F2 in the Resonance Region and Evaluation of Its Moments
We measured the inclusive electron-proton cross section in the nucleon
resonance region (W < 2.5 GeV) at momentum transfers Q**2 below 4.5 (GeV/c)**2
with the CLAS detector. The large acceptance of CLAS allowed for the first time
the measurement of the cross section in a large, contiguous two-dimensional
range of Q**2 and x, making it possible to perform an integration of the data
at fixed Q**2 over the whole significant x-interval. From these data we
extracted the structure function F2 and, by including other world data, we
studied the Q**2 evolution of its moments, Mn(Q**2), in order to estimate
higher twist contributions. The small statistical and systematic uncertainties
of the CLAS data allow a precise extraction of the higher twists and demand
significant improvements in theoretical predictions for a meaningful comparison
with new experimental results.Comment: revtex4 18 pp., 12 figure
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