149 research outputs found
UV/IR Mixing for Noncommutative Complex Scalar Field Theory, II (Interaction with Gauge Fields)
We consider noncommutative analogs of scalar electrodynamics and N=2 D=4 SUSY
Yang-Mills theory. We show that one-loop renormalizability of noncommutative
scalar electrodynamics requires the scalar potential to be an anticommutator
squared. This form of the scalar potential differs from the one expected from
the point of view of noncommutative gauge theories with extended SUSY
containing a square of commutator. We show that fermion contributions restore
the commutator in the scalar potential. This provides one-loop
renormalizability of noncommutative N=2 SUSY gauge theory. We demonstrate a
presence of non-integrable IR singularities in noncommutative scalar
electrodynamics for general coupling constants. We find that for a special
ratio of coupling constants these IR singularities vanish. Also we show that IR
poles are absent in noncommutative N=2 SUSY gauge theory.Comment: 9 pages, 16 EPS figure
Satellite observations of plasma-wave disturbances induced by high-power radio emission from the NWC transmitter
In this work, we present the results of in-situ measurements of the characteristics of electromagnetic and plasma disturbances in the ionospheric region modified by high-power emission from the NWC transmitter, which were obtained using the onboard equipment of the French microsatellite DEMETER. It is shown that under the influence of VLF emissions from the ground-based transmitters, artificial plasma-wave channels with typical transverse scales of about 1000 km can be formed in the ionospheric plasma.Представлены результаты непосредственных (in-situ) измерений бортовой аппаратурой французского микроспутника DEMETER характеристик электромагнитных и плазменных возмущений в модифицированной мощным излучением передатчика NWC области ионосферы. Отмечено, что при воздействии ОНЧ-излучения наземных передатчиков в ионосферной плазме формируются искусственные плазменно-волновые каналы с характерным поперечным масштабом ~ 1000 км.Представлені результати безпосередніх (in-situ) вимірювань бортовою апаратурою французького мікросупутника DEMETER характеристик електромагнітних і плазмових збурень у модифікованій потужним випромінюванням передавача NWC області іоносфери. Відзначено, що при впливі ОНЧ- випромінювання наземних передавачів в іоносферній плазмі формуються штучні плазмово-хвильові канали з характерним поперечним масштабом ~ 1000 км
Quantizing non-Lagrangian gauge theories: an augmentation method
We discuss a recently proposed method of quantizing general non-Lagrangian
gauge theories. The method can be implemented in many different ways, in
particular, it can employ a conversion procedure that turns an original
non-Lagrangian field theory in dimensions into an equivalent Lagrangian
topological field theory in dimensions. The method involves, besides the
classical equations of motion, one more geometric ingredient called the
Lagrange anchor. Different Lagrange anchors result in different quantizations
of one and the same classical theory. Given the classical equations of motion
and Lagrange anchor as input data, a new procedure, called the augmentation, is
proposed to quantize non-Lagrangian dynamics. Within the augmentation
procedure, the originally non-Lagrangian theory is absorbed by a wider
Lagrangian theory on the same space-time manifold. The augmented theory is not
generally equivalent to the original one as it has more physical degrees of
freedom than the original theory. However, the extra degrees of freedom are
factorized out in a certain regular way both at classical and quantum levels.
The general techniques are exemplified by quantizing two non-Lagrangian models
of physical interest.Comment: 46 pages, minor correction
Tachyon condensation in cubic superstring field theory
It has been conjectured that at the stationary point of the tachyon potential
for the non-BPS D-brane or brane-anti-D-brane pair, the negative energy density
cancels the brane tension. We study this conjecture using a cubic superstring
field theory with insertion of a double-step inverse picture changing operator.
We compute the tachyon potential at levels (1/2,1) and (2,6). In the first case
we obtain that the value of the potential at the minimum is 97.5% of the non
BPS D-brane tension. Using a special gauge in the second case we get 105.8% of
the tension.Comment: 19 pages, LaTeX, 3 figures. Eqs. (3.2), (3.3) and (4.6) are
corrected, and new gauge fixing condition is use
Formality theorems for Hochschild complexes and their applications
We give a popular introduction to formality theorems for Hochschild complexes
and their applications. We review some of the recent results and prove that the
truncated Hochschild cochain complex of a polynomial algebra is non-formal.Comment: Submitted to proceedings of Poisson 200
Gauge Invariance and Tachyon Condensation in Cubic Superstring Field Theory
The gauge invariance of cubic open superstring field theory is considered in
a framework of level truncation, and applications to the tachyon condensation
problem are discussed. As it is known, in the bosonic case the Feynman-Siegel
gauge is not universal within the level truncation method. We explore another
gauge that is more suitable for calculation of the tachyon potential for
fermionic string at level (2,6). We show that this new gauge has no
restrictions on the region of its validity at least at this level.Comment: 21 pages, 2 figures, LaTeX 2e; references added, typos correcte
H⁻ injector for Moscow meson factory linac
Status report is presented for an H⁻ injector being now under construction. The injector parameters are as follows: energy − 400 keV; average beam current − 400 µA; beam pulse duration − up to 200 µs; pulse repetition rate − 50 Hz. A pulsed high-voltage generator and a surface-plasma ion source power supply have been developed and
manufactured.Представлено состоянии работ по созданию инжектора отрицательных ионов водорода с энергией
400 кВ, который должен обеспечить средний ток пучка ионов до 400 мкА при длительности импульса тока
до 200 мкс и частоте повторения импульсов 50 Гц. Разработаны, изготовлены и смонтированы генератор
ускоряющего импульсного напряжения и система питания поверхностно-плазменного ионного источника.Представлено звіт про стан робіт зі створення інжектора негативних іонів водню з енергією 400 кВ, що
повинен забезпечити середній струм пучка іонів до 400 мкА при тривалості імпульсу струму пучка до
200 мкс і частоті повторення імпульсів 50 Гц. Розроблено, виготовлені і змонтовані генератор
прискорювальної імпульсної напруги і система живлення поверхнево-плазмового іонного джерел
AEGIS at CERN: Measuring Antihydrogen Fall
The main goal of the AEGIS experiment at the CERN Antiproton Decelerator is
the test of fundamental laws such as the Weak Equivalence Principle (WEP) and
CPT symmetry. In the first phase of AEGIS, a beam of antihydrogen will be
formed whose fall in the gravitational field is measured in a Moire'
deflectometer; this will constitute the first test of the WEP with antimatter.Comment: Presented at the Fifth Meeting on CPT and Lorentz Symmetry,
Bloomington, Indiana, June 28-July 2, 201
Temporal evolution of solar energetic particle spectra
During solar flares and coronal mass ejections, solar energetic par- ticles (SEPs) may be released into the interplanetary medium and near-Earth locations. The energy spectra of SEP events at 1 AU are typically averaged over the entire event or studied in a few snapshots. In this paper we analyze the time evolution of the energy spectra of four large selected SEP events using a large number of snapshots. We use a multi-spacecraft and multi-instrument approach for the observations, obtained over a wide SEP energy range. We find large differences in the spectra at the beginning of the events as measured by different instruments. We show that over time, a wave-like structure is observed traveling through the spectra from the highest energies to the lowest energies, creating an “arch” shape which then straightens into a power law later in the event, after times of the order of 10 hours. We discuss the processes that determine SEP intensities and their role in shaping the spectral time evolution
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