15 research outputs found
Generation of magnetic and chromomagnetic fields at high temperature in the standard model
The spontaneous generation of the magnetic and chromomagnetic fields at high temperature is investigated in the Standard Model. The consistent effective potential including the one-loop and the daisy diagrams of all boson and fermion fields is calculated. The mixing of the generated fields due to the quark loop diagram is studied
The Effective electromagnetic interaction in a dense fermionic medium in QED_{2+1}
The effective Lagrangian of arbitrary varying in space electromagnetic field
in a dense medium is derived. It has been used for investigation of interaction
between charged fermions in the medium. It is shown the possibility for the
formation of metastable electron bound states in the medium when external
magnetic field is applied.Comment: 6 pages, LaTeX, 1 figure (PS file), minor change
On the type of the temperature phase transition in O(N) models
The temperature induced phase transition is investigated in the O(N) models by using graphics processing units (GPU) for Monte Carlo simulations on a lattice. General purpose computing on GPU (GPGPU) technology allows to collect a huge amount of data that gives a possibility to investigate the type of the phase transition for a wide interval of coupling values. It is found that for the small values of λ a weak-first-order phase transition happens. It converts into a second order phase transition with the increase of λ. A comparison with analytic calculations in continuum field theory and lattice simulations obtained by other authors is given.Исследован температурный фазовый переход в O(N)-моделях с помощью использования графических видеокарт (GPU) для Монте-Карло симуляций на решетке. Технология расчетов общего назначения на видеокартах (GPGPU) сделала возможным собрать огромное количество данных, позволивших исследовать тип фазового перехода в широком интервале значений константы связи. Найдено, что для малых значений величин λ наблюдается фазовый переход первого рода. С ростом константы связи λ фазовый переход становится фазовым переходом второго рода. Представлено сравнение результатов с результатами, полученными другими авторами с помощью аналитических вычислений в континуальной теории и решеточных симуляций.Досліджено температурний фазовий перехід в O(N)-моделях за допомогою використання графічних відеокарт (GPU) у Монте-Карло симуляціях на решітці. Технологія розрахунків загального призначення на відеокартах (GPGPU) зробила можливим зібрати величезну кількість даних, які дозволили дослідити тип фазового переходу в широкому інтервалі значень константи зв'язку. Знайдено, що для малих значень величин λ спостерігається фазовий перехід першого роду. З ростом константи зв'язку λ фазовий перехід стає фазовим переходом другого роду. Представлено порівняння результатів з результатами, отриманими іншими авторами за допомогою аналітичних обчислень у континуальній теорії та симуляцій на решітках
Model-independent Z' searches at modern colliders
The model-independent constraints on the Abelian Z' couplings from the LEP data are applied to estimate the Z' production in experiments at hadron colliders. The Z' contribution to the Drell-Yan process at modern hadron colliders is analyzed. The results are compared with model-dependent predictions and present experimental data from the Tevatron and the LHC. The lower bounds on the Z' mass are derived and the Z' discovery limit in the LHC experiments is found.С помощью модельно-независимых ограничений на константы связи абелевого Z'-бозона получены оценки процессов рождения Z' в экспериментах на адронных коллайдерах. Изучен вклад Z'-бозона в процесс Дрелла-Яна. Проведено сравнение полученных результатов с модельно-зависимыми предсказаниями и экспериментальными данными ускорителей Tevatron и LHC. Получена нижняя граница значения массы Z'-бозона, а также предельные значения массы, при которых Z' будет обнаружен в эксперименте LHC.За допомогою модельно-незалежних обмежень констант зв’язку абелевого Z'-бозона отримано оцінки процесів народження Z'-бозона в експериментах на гадронних колайдерах. Досліджено внесок Z' в процес Дрелла-Яна. Виконано порівняння отриманих результатів з модельно-залежними результатами та експериментальними даними прискорювачів Tevatron та LHC. Отримана нижня границя маси Z'-бозона, а також граничні значення маси, при яких Z'-бозон буде знайдено в експериментах LHC
Phase of the Wilson Line at High Temperature in the Standard Model
We compute the effective potential for the phase of the Wilson line at high
temperature in the standard model to one loop order. Besides the trivial vacua,
there are metastable states in the direction of hypercharge. Assuming
that the universe starts out in such a metastable state at the Planck scale, it
easily persists to the time of the electroweak phase transition, which then
proceeds by an unusual mechanism. All remnants of the metastable state
evaporate about the time of the phase transition.Comment: 4 pages in ReVTeX plus 1 figure; Columbia Univ. preprint CU-TP-63
Neutrino Propagation in a Strongly Magnetized Medium
We derive general expressions at the one-loop level for the coefficients of
the covariant structure of the neutrino self-energy in the presence of a
constant magnetic field. The neutrino energy spectrum and index of refraction
are obtained for neutral and charged media in the strong-field limit () using the lowest Landau level
approximation. The results found within the lowest Landau level approximation
are numerically validated, summing in all Landau levels, for strong and weakly-strong fields. The neutrino energy in
leading order of the Fermi coupling constant is expressed as the sum of three
terms: a kinetic-energy term, a term of interaction between the magnetic field
and an induced neutrino magnetic moment, and a rest-energy term. The leading
radiative correction to the kinetic-energy term depends linearly on the
magnetic field strength and is independent of the chemical potential. The other
two terms are only present in a charged medium. For strong and weakly-strong
fields, it is found that the field-dependent correction to the neutrino energy
in a neutral medium is much larger than the thermal one. Possible applications
to cosmology and astrophysics are considered.Comment: 23 pages, 4 figures. Corrected misprints in reference
Magnetism in Dense Quark Matter
We review the mechanisms via which an external magnetic field can affect the
ground state of cold and dense quark matter. In the absence of a magnetic
field, at asymptotically high densities, cold quark matter is in the
Color-Flavor-Locked (CFL) phase of color superconductivity characterized by
three scales: the superconducting gap, the gluon Meissner mass, and the
baryonic chemical potential. When an applied magnetic field becomes comparable
with each of these scales, new phases and/or condensates may emerge. They
include the magnetic CFL (MCFL) phase that becomes relevant for fields of the
order of the gap scale; the paramagnetic CFL, important when the field is of
the order of the Meissner mass, and a spin-one condensate associated to the
magnetic moment of the Cooper pairs, significant at fields of the order of the
chemical potential. We discuss the equation of state (EoS) of MCFL matter for a
large range of field values and consider possible applications of the magnetic
effects on dense quark matter to the astrophysics of compact stars.Comment: To appear in Lect. Notes Phys. "Strongly interacting matter in
magnetic fields" (Springer), edited by D. Kharzeev, K. Landsteiner, A.
Schmitt, H.-U. Ye
Automation of monitoring and exploitation management of pointwork electric motor parks based of the parameters of current technical state
Exploitation technology of pointwork electric motor parks is developed based on the fuzzy-statistical expert system. Technology includes monitoring and diagnostics of engine current technical state without an exception from a drive, allows defining the order of engine repairs
Automation of planning the heterogeneous dynamic streams in transport networks
The dynamic streams, when stream units have individual characteristics (heterogeneity), are analyzed in the article