2,440 research outputs found
Supersymmetric Gauge Field Theory and String Theory
Designed as a sequel to the authors' Introduction to Gauge Field Theory, Supersymmetric Gauge Field Theory and String Theory introduces first-year graduate students to supersymmetric theories, including supergravity and superstring theories. Starting with the necessary background in quantum field theory, the book covers the three key topics of high-energy physics. The emphasis is on practical calculations rather than abstract generalities or phenomenological results. Where possible, the authors show how to calculate, connecting the theoretical with the phenomenological. While the field continues to advance and grow, this book addresses the basic theory at the core and will likely remain relevant even if more advanced ideas change
Introduction to Gauge Field Theory Revised Edition
Introduction to Gauge Field Theory provides comprehensive coverage of modern relativistic quantum field theory, emphasizing the details of actual calculations rather than the phenomenology of the applications. Forming a foundation in the subject, the book assumes knowledge of relativistic quantum mechanics, but not of quantum field theory. The boo
Cosmology in Gauge Field Theory and String Theory
Cosmology in Gauge Field Theory and String Theory focuses on the cosmological implications of the gauge theories of particle physics and of string theory. The book first examines the universe's series of phase transitions in which the successive gauge symmetries of the higher-temperature phase were spontaneously broken after the big bang, discussing relics of these phase transitions, more generic relics (baryons, neutrinos, axions), and supersymmetric particles (neutralinos and gravitinos). The author next studies supersymmetric theory, supergravity theory, and the constraints on the underlying field theory of the universe's inflationary era. The book concludes with a discussion of black hole solutions of the supergravity theory that approximates string theory at low energies and the insight that string theory affords into the microscopic origin of the Bekenstein-Hawking entropy. Cosmology in Gauge Field Theory and String Theory provides a modern introduction to these important problems from a particle physicist's perspective. It is intended as an introductory textbook for a first course on the subject at a graduate level
Phonon-phonon interactions and phonon damping in carbon nanotubes
We formulate and study the effective low-energy quantum theory of interacting
long-wavelength acoustic phonons in carbon nanotubes within the framework of
continuum elasticity theory. A general and analytical derivation of all three-
and four-phonon processes is provided, and the relevant coupling constants are
determined in terms of few elastic coefficients. Due to the low dimensionality
and the parabolic dispersion, the finite-temperature density of noninteracting
flexural phonons diverges, and a nonperturbative approach to their interactions
is necessary. Within a mean-field description, we find that a dynamical gap
opens. In practice, this gap is thermally smeared, but still has important
consequences. Using our theory, we compute the decay rates of acoustic phonons
due to phonon-phonon and electron-phonon interactions, implying upper bounds
for their quality factor.Comment: 15 pages, 2 figures, published versio
Holey fibre mode-selective couplers
Mode-selective coupling in an asymmetric holey fibre coupler is demonstrated both numerically and experimentally for the first
time. The coupler's performance is shown to be ultrabroadband, with significant potential existing for the use of such
couplers in high bandwidth few-mode fibre networks
Tautomerisation and hydrogen-bonding interactions in four-coordinate metal halide and azide complexes of N-donor-extended dipyrromethanes (vol 39, pg 2851, 2010)
The enigmatic multiple star VV Ori
New photometry, including TESS data, have been combined with recent
spectroscopic observations of the Orion Ib pulsating triple-star system VV Ori.
This yields a revised set of absolute parameters with increased precision. Two
different programs were utilized for the light curve analysis, with results in
predictably close agreement. The agreement promotes confidence in the analysis
procedures. The spectra were analysed using the {\sc FDBinary} program. The
main parameters are as follows: and
(M). We estimate an approximate mass of the wide companion as M. Similarly, , , (R); , and (K). The close
binary's orbital separation is (R); its age is
(Myr) and its photometric distance is pc. The primary's Cep
type oscillations support these properties and confirm our understanding of its
evolutionary status. Examination of the well-defined 6678 He I
profiles reveals the primary to have a significantly low projected rotation:
some 80\% of the synchronous value. This can be explained on the basis of the
precession of an unaligned spin axis. This proposal can resolve also observed
variations of the apparent inclination and address other longer-term
irregularities of the system reported in the literature. This topic invites
further observations and follow-up theoretical study of the dynamics of this
intriguing young multiple star.Comment: 17 pages, 15 figures, 14 tables, accepted by MNRA
Simple Amides and Amines for the Synergistic Recovery of Rhodium from Hydrochloric Acid by Solvent Extraction
Fistula awareness among sisters of women with fistula
ObjectiveTo determine whether sisters of women with obstetric fistula (OF) were aware of their sistersâ condition, in order to inform the development of survey questions that adapt the sisterâbased method to fistula rate estimation.MethodsTwelve women with OF and 20 of their sisters were interviewed using semiâstructured questionnaires in rural Uganda in 2007. Topics included fistula awareness and perceptions of causality.ResultsEleven women had vesicovaginal fistula and 1 had rectovaginal fistula. Three were primiparous at time of fistula occurrence; 6 had a parity of 6 or more. Nineteen sisters were aware their sister had OF; 12 became aware at the time of occurrence. The majority of participants (fistula patients and their sisters) associated OF with mistakes made by hospital personnel or problems during procedures.ConclusionSisters were generally aware of OF within their family. Larger studies are needed to assess the validity and reliability of the sisterâbased method in capturing fistula through household surveys. In the present study, there was a widespread perception among fistula patients and their sisters that fistula is caused by medical procedures. More research is needed to understand this perception, and program development efforts are required to improve patient perceptions of hospital care.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135323/1/ijgo232.pd
Observation of the Dependence of Scintillation from Nuclear Recoils in Liquid Argon on Drift Field
We have exposed a dual-phase Liquid Argon Time Projection Chamber (LAr-TPC)
to a low energy pulsed narrowband neutron beam, produced at the Notre Dame
Institute for Structure and Nuclear Astrophysics to study the scintillation
light yield of recoiling nuclei in a LAr-TPC. A liquid scintillation counter
was arranged to detect and identify neutrons scattered in the LAr-TPC target
and to select the energy of the recoiling nuclei.
We report the observation of a significant dependence on drift field of
liquid argon scintillation from nuclear recoils of 11 keV. This observation is
important because, to date, estimates of the sensitivity of noble liquid TPC
dark matter searches are based on the assumption that electric field has only a
small effect on the light yield from nuclear recoils.Comment: v3 updated to reflect published version, including a set of plots for
49.9 keV dat
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