21,130 research outputs found
Canonical Quantization of the Self-Dual Model coupled to Fermions
This paper is dedicated to formulate the interaction picture dynamics of the
self-dual field minimally coupled to fermions. To make this possible, we start
by quantizing the free self-dual model by means of the Dirac bracket
quantization procedure. We obtain, as result, that the free self-dual model is
a relativistically invariant quantum field theory whose excitations are
identical to the physical (gauge invariant) excitations of the free
Maxwell-Chern-Simons theory. The model describing the interaction of the
self-dual field minimally coupled to fermions is also quantized through the
Dirac bracket quantization procedure. One of the self-dual field components is
found not to commute, at equal times, with the fermionic fields. Hence, the
formulation of the interaction picture dynamics is only possible after the
elimination of the just mentioned component. This procedure brings, in turns,
two new interaction terms, which are local in space and time while
non-renormalizable by power counting. Relativistic invariance is tested in
connection with the elastic fermion-fermion scattering amplitude. We prove that
all the non-covariant pieces in the interaction Hamiltonian are equivalent to
the covariant minimal interaction of the self-dual field with the fermions. The
high energy behavior of the self-dual field propagator corroborates that the
coupled theory is non-renormalizable. Certainly, the self-dual field minimally
coupled to fermions bears no resemblance with the renormalizable model defined
by the Maxwell-Chern-Simons field minimally coupled to fermions.Comment: 16 pages, no special macros, no corrections in the pape
Magnetic glass in Shape Memory Alloy : Ni45Co5Mn38Sn12
The first order martensitic transition in the ferromagnetic shape memory
alloy Ni45Co5Mn38Sn12 is also a magnetic transition and has a large field
induced effect. While cooling in the presence of field this first order
magnetic martensite transition is kinetically arrested. Depending on the
cooling field, a fraction of the arrested ferromagnetic austenite phase
persists down to the lowest temperature as a magnetic glassy state, similar to
the one observed in various intermetallic alloys and in half doped manganites.
A detailed investigation of this first order ferromagnetic austenite (FM-A) to
low magnetization martensite (LM-M) state transition as a function of
temperature and field has been carried out by magnetization measurements.
Extensive cooling and heating in unequal field (CHUF) measurements and a novel
field cooled protocol for isothermal MH measurements (FC-MH) are utilized to
investigate the glass like arrested states and show a reverse martensite
transition. Finally, we determine a field -temperature (HT) phase diagram of
Ni45Co5Mn38Sn12 from various magnetization measurements which brings out the
regions where thermodynamic and metastable states co-exist in the HT space
clearly depicting this system as a 'Magnetic Glass'.Comment: Magnetic field tunes kinetic arrest and CHUF shows devitrification
and melting of Magnetic glas
On the constrained structure of duality symmetric Maxwell theory
The constrained structure of the duality invariant form of Maxwell theory is
considered in the Hamiltonian formulation of Dirac as well as from the
symplectic viewpoint. Compared to the former the latter approach is found to be
more economical and elegant. Distinctions from the constrained analysis of the
usual Maxwell theory are pointed out and their implications are also discussed.Comment: Latex, 12 page
Health outcomes of children born to mothers with chronic kidney disease: a pilot study
This study aimed to study the health of children born to mothers with chronic kidney disease. Twenty-four children born to mothers with chronic kidney disease were compared with 39 matched control children born to healthy mothers without kidney disease. The well-being of each child was individually assessed in terms of physical health, neurodevelopment and psychological health. Families participating with renal disease were more likely to be from lower socio-economic backgrounds. Significantly fewer vaginal deliveries were reported for mothers with renal disease and their infants were more likely to experience neonatal morbidity. Study and control children were comparable for growth parameters and neurodevelopment as assessed by the Griffiths scales. There was no evidence of more stress amongst mothers with renal disease or of impaired bonding between mother and child when compared to controls. However, there was evidence of greater externalizing behavioral problems in the group of children born to mothers with renal disease. Engaging families in such studies is challenging. Nonetheless, families who participated appreciated being asked. The children were apparently healthy but there was evidence in this small study of significant antenatal and perinatal morbidity compared to controls. Future larger multi-center studies are required to confirm these early findings
Approximations from Anywhere and General Rough Sets
Not all approximations arise from information systems. The problem of fitting
approximations, subjected to some rules (and related data), to information
systems in a rough scheme of things is known as the \emph{inverse problem}. The
inverse problem is more general than the duality (or abstract representation)
problems and was introduced by the present author in her earlier papers. From
the practical perspective, a few (as opposed to one) theoretical frameworks may
be suitable for formulating the problem itself. \emph{Granular operator spaces}
have been recently introduced and investigated by the present author in her
recent work in the context of antichain based and dialectical semantics for
general rough sets. The nature of the inverse problem is examined from
number-theoretic and combinatorial perspectives in a higher order variant of
granular operator spaces and some necessary conditions are proved. The results
and the novel approach would be useful in a number of unsupervised and semi
supervised learning contexts and algorithms.Comment: 20 Pages. Scheduled to appear in IJCRS'2017 LNCS Proceedings,
Springe
BFFT quantization with nonlinear constraints
We consider the method due to Batalin, Fradkin, Fradkina, and Tyutin (BFFT)
that makes the conversion of second-class constraints into first-class ones for
the case of nonlinear theories. We first present a general analysis of an
attempt to simplify the method, showing the conditions that must be fulfilled
in order to have first-class constraints for nonlinear theories but that are
linear in the auxiliary variables. There are cases where this simplification
cannot be done and the full BFFT method has to be used. However, in the way the
method is formulated, we show with details that it is not practicable to be
done. Finally, we speculate on a solution for these problems.Comment: 19 pages, Late
Batalin-Tyutin Quantization of the Self-Dual Massive Theory in Three Dimensions
We quantize the self-dual massive theory by using the Batalin-Tyutin
Hamiltonian method, which systematically embeds second class constraint system
into first class one in the extended phase space by introducing the new fields.
Through this analysis we obtain simultaneously the St\"uckelberg scalar term
related to the explicit gauge-breaking effect and the new type of Wess-Zumino
action related to the Chern-Simons term.Comment: 17 pages, SOGANG-HEP 191/9
Recursive Construction of Generator for Lagrangian Gauge Symmetries
We obtain, for a subclass of structure functions characterizing a first class
Hamiltonian system, recursive relations from which the general form of the
local symmetry transformations can be constructed in terms of the independent
gauge parameters. We apply this to a non-trivial Hamiltonian system involving
two primary constraints, as well as two secondary constraints of the Nambu-Goto
type.Comment: 10 pages, Late
Komar energy and Smarr formula for noncommutative Schwarzschild black hole
We calculate the Komar energy for a noncommutative Schwarzschild black
hole. A deformation from the conventional identity is found in the
next to leading order computation in the noncommutative parameter
(i.e. ) which is also consistent
with the fact that the area law now breaks down. This deformation yields a
nonvanishing Komar energy at the extremal point of these black holes.
We then work out the Smarr formula, clearly elaborating the differences from
the standard result , where the mass () of the black hole is
identified with the asymptotic limit of the Komar energy. Similar conclusions
are also shown to hold for a deSitter--Schwarzschild geometry.Comment: 5 pages Late
Cu_{2}O as nonmagnetic semiconductor for spin transport in crystalline oxide electronics
We probe spin transport in Cu_{2}O by measuring spin valve effect in
La_{0.7}Sr_{0.3}MnO_{3}/Cu_{2}O/Co and
La_{0.7}Sr_{0.3}MnO_{3}/Cu_{2}O/La_{0.7}Sr_{0.3}MnO_{3} epitaxial
heterostructures. In La_{0.7}Sr_{0.3}MnO_{3}/Cu_{2}O/Co systems we find that a
fraction of out-of-equilibrium spin polarized carrier actually travel across
the Cu_{2}O layer up to distances of almost 100 nm at low temperature. The
corresponding spin diffusion length dspin is estimated around 40 nm.
Furthermore, we find that the insertion of a SrTiO_{3} tunneling barrier does
not improve spin injection, likely due to the matching of resistances at the
interfaces. Our result on dspin may be likely improved, both in terms of
Cu_{2}O crystalline quality and sub-micrometric morphology and in terms of
device geometry, indicating that Cu_{2}O is a potential material for efficient
spin transport in devices based on crystalline oxides.Comment: 15 pages, 10 figure
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