10,651 research outputs found
Nilpotent invariants in N=4 SYM
It is shown that there are no nilpotent invariants in N=4 analytic superspace
for points. It is argued that there is (at least) one such invariant
for n=5 points which is not invariant under U(1)_Y. The consequences of these
results are that the n=2 and 3 point correlation functions of the N=4
gauge-invariant operators which correspond to KK multiplets in AdS supergravity
are given exactly by their tree level expressions, the 4 point correlation
functions of such operators are invariant under U(1)_Y and correlation
functions with points have non-trivial dependence on the Yang-Mills
coupling constant.Comment: 9 page
Experimental characterization of a supercapacitor-based electrical torque-boost system for downsized ICE vehicles
The need to improve fuel economy and reduce the emission of CO2 and other harmful pollution from internal-combustion-engine vehicles has led to engine downsizing. However, downsized turbocharged engines exhibit a relatively low torque capability at low engine speeds. To overcome this problem, an electrical torque boost may be employed while accelerating and changing gear and to facilitate energy recovery during regenerative braking. This paper describes the operational requirements of a supercapacitor-based torque-boost system, outlines the design and sizing of the electrical drive-train components, and presents experimental characterization of a demonstrator system
Four-point functions in N=2 superconformal field theories
Four-point correlation functions of hypermultiplet bilinear composites are
analysed in N=2 superconformal field theory using the superconformal Ward
identities and the analyticity properties of the composite operator
superfields. It is shown that the complete amplitude is determined by a single
arbitrary function of the two conformal cross-ratios of the space-time
variables.Comment: 36 pp LaTeX2e, uses amsfonts, amssymb. Some references adde
Partial non-renormalisation of the stress-tensor four-point function in N=4 SYM and AdS/CFT
We show that, although the correlator of four stress-tensor multiplets in N=4
SYM is known to have radiative corrections, certain linear combinations of its
components are protected from perturbative renormalisation and remain at their
free-field values. This result is valid for weak as well as for strong coupling
and for any gauge group. Our argument uses Intriligator's insertion formula,
and includes a proof that the possible contact term contributions cannot change
the form of the amplitudes. Combining this new non-renormalisation theorem with
Maldacena's conjecture allows us to make a prediction for the structure of the
corresponding correlator in AdS supergravity. This is verified by first
considerably simplifying the strong coupling expression obtained by recent
supergravity calculations, and then showing that it does indeed exhibit the
expected structure.Comment: 21 pages, no figure
A Comparative Study of Scholastic Achievement between Day and Dormitory High School Students in Ankara, Turkey
The primary purpose of this study was to compare the scholastic achievement of dormitory students and day students after both groups entered Ankara American High School
Regarding themselves as permanently settled : An Ethnohistory of Cherokee Hyper-Displacement
“Regarding themselves as permanently settled” analyzes displacement and resettlement of four Cherokee regions and sets of communities during the first few decades of the nineteenth century. Instead of parsing out various Cherokee removal episodes of the period, this dissertation moves across time and space to foreground the human experiences as expressed by the displaced Cherokees themselves. Instead of utilizing a framework of Euro-American removal tactics to compartmentalize, marginalize and silence tribal agency throughout displacement episodes, what were the social elements of individual and collective networks utilized to navigate removal, and subsequent responses to newly constituted social networks when forming new communities in a post-displacement setting. I foreground existing tribal culturally grounded manifestations of self-determination to understand the importance of family and kin during times of isolation and stress, a process I refer to as hyper-displacement. Additionally, this dissertation emphasizes the uniquely centered Cherokee cultural components of tohi (balance, or walking the correct way, the open way), and osi (life in a good state) within larger discourses surrounding the normalization of violence experienced by indigenous populations throughout the early establishment of federal Indian policy.My main data-sets were collections of sworn affidavits, depositions, memorials, and spoliation claims presented by individual Cherokees over a twenty-year period. Most often these data-sets were presented by Cherokees seeking monetary recompense of their removal from homes and farms to the very federal agents who had legislatively, economically and forcibly removed them. The application of an ethnohistorical ethnographic approach to these archival materials, what I call archival participant observation, emphasizes new perspectives to analyze Cherokee towns not necessarily just predicated on a specific location, but as organically interconnected networks of mutual aid and fellowship. While this dissertation is grounded in a nineteenth century Cherokee perspective of displacement and post-displacement community construction, it provides insight to understand the wider implications of how individuals and communities navigate displacement. This dissertation illustrates that sometimes all we have are our social and familial networks, and the lengths people centralize them following displacement
BRST quantization of matrix models with constraints and two-dimensional Yang-Mills theory on the cylinder
BRST quantization of the one-dimensional constrained matrix model which
describes two-dimensional Yang-Mills theory on the cylinder is performed.
Classical and quantum BRST generators and BRST-invariant hamiltonians are
constructed. Evolution operator is expressed in terms of BRST path integral.
Advantages of the BRST quantization over the reduced phase space approach
leading to the theory of free fermions are discussed.Comment: 8 page
Holonomy groups and W-symmetries
Irreducible sigma models, i.e. those for which the partition function does
not factorise, are defined on Riemannian spaces with irreducible holonomy
groups. These special geometries are characterised by the existence of
covariantly constant forms which in turn give rise to symmetries of the
supersymmetric sigma model actions. The Poisson bracket algebra of the
corresponding currents is a W-algebra. Extended supersymmetries arise as
special cases.Comment: pages 2
A Reference-Free Algorithm for Computational Normalization of Shotgun Sequencing Data
Deep shotgun sequencing and analysis of genomes, transcriptomes, amplified
single-cell genomes, and metagenomes has enabled investigation of a wide range
of organisms and ecosystems. However, sampling variation in short-read data
sets and high sequencing error rates of modern sequencers present many new
computational challenges in data interpretation. These challenges have led to
the development of new classes of mapping tools and {\em de novo} assemblers.
These algorithms are challenged by the continued improvement in sequencing
throughput. We here describe digital normalization, a single-pass computational
algorithm that systematizes coverage in shotgun sequencing data sets, thereby
decreasing sampling variation, discarding redundant data, and removing the
majority of errors. Digital normalization substantially reduces the size of
shotgun data sets and decreases the memory and time requirements for {\em de
novo} sequence assembly, all without significantly impacting content of the
generated contigs. We apply digital normalization to the assembly of microbial
genomic data, amplified single-cell genomic data, and transcriptomic data. Our
implementation is freely available for use and modification
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