Optical phonon scattering and theory of magneto-polarons in a quantum cascade laser in a strong magnetic field

We report a theoretical study of the carrier relaxation in a quantum cascade laser (QCL) subjected to a strong magnetic field. Both the alloy (GaInAs) disorder effects and the Frohlich interaction are taken into account when the electron energy differences are tuned to the longitudinal optical (LO) phonon energy. In the weak electron-phonon coupling regime, a Fermi's golden rule computation of LO phonon scattering rates shows a very fast non-radiative relaxation channel for the alloy broadened Landau levels (LL's). In the strong electron-phonon coupling regime, we use a magneto-polaron formalism and compute the electron survival probabilities in the upper LL's with including increasing numbers of LO phonon modes for a large number of alloy disorder configurations. Our results predict a nonexponential decay of the upper level population once electrons are injected in this state.Comment: 10 pages, 23 figure

Diffractive gauge bosons production beyond QCD factorisation

We discuss single diffractive gauge bosons ($\gamma^*,\,W^{\pm},\,Z$) production in proton-proton collisions at different (LHC and RHIC) energies within the color dipole approach. The calculations are performed for gauge bosons produced at forward rapidities. The diffractive cross section is predicted as function of fractional momentum and invariant mass of the lepton pair. We found a dramatic breakdown of the diffractive QCD factorisation caused by an interplay of hard and soft interactions. Data from the CDF experiment on diffractive production of $W$ and $Z$ are well explained in a parameter free way.Comment: 28 pages, 10 figures; a clarification of absorptive corrections has been added, typos corrected; the published versio

Large Rapidity Gap Processes in Proton-Nucleus Collisions

The cross sections for a variety of channels of proton-nucleus interaction associated with large gaps in rapidity are calculated within the Glauber-Gribov theory. We found inelastic shadowing corrections to be dramatically enhanced for such events. We employ the light-cone dipole formalism which allows to calculate the inelastic corrections to all orders of the multiple interaction. Although Gribov corrections are known to make nuclear matter more transparent, we demonstrate that in some instances they lead to an opaqueness. Numerical calculations are performed for the energies of the HERA-B experiment, and the RHIC-LHC colliders.Comment: 19 page

Клинический случай поражения молнией

Atmospheric electricity damage as a result of lightning strike is a relatively rare condition in intensive care medicine, however it can be accompanied by high mortality and serious complications in the majority of survived patients.The objective was to demonstrate a clinical case of lightning injury and discussion of diagnostic and treatment aspects in this condition.Materials and Methods. 18-yr old patient was delivered to hospital after lightning strike. She lost consciousness, there was no breathing for a short time, and the witnesses provided artificial respiration and external cardiac compressions. On admission, the signs of shock were present in parallel with dopamine infusion, the skin was pale-grey and cold, with traces of thermal damage according to the type of contact with metal of various localization on the neck, scalp, front surface of the chest and abdominal wall, in the groin, on the left foot. The patient was hospitalized to ICU, therapeutic and diagnostic measures were started. We revealed decompensated lactic acidosis, biochemical signs of myocardial and muscle damage. The infusion therapy, analgesics, antibiotics, proton pump inhibitors, anticoagulants were administered. During the therapy in the first 6 hours, the signs of shock were attenuated, in 4 days, the patient was transferred to traumatological department in a stable state. After the transfer from the ICU, hearing decline as well as pain and sensory disturbances in the left foot are persisting.Conclusion. An integrated approach is required in the diagnosis, treatment, and rehabilitation of patients with lightning injury.Поражение атмосферным электричеством в результате удара молнии – состояние, достаточно редко встречающееся в реанимационной практике; вместе с тем, оно сопровождается высокой смертностью и серьезными осложнениями у значительной части выживших пациентов.Цель – демонстрация клинического наблюдения поражения атмосферным электричеством и обсуждение аспектов диагностики и лечения данной патологии.Материалы и методы. Пациентка 18 лет доставлена в стационар после поражения молнией на берегу. Отмечалась потеря сознания, кратковременно отсутствовало дыхание, свидетели происшествия проводили искусственное дыхание и наружный массаж сердца. При поступлении – признаки шока на фоне инфузии допамина, кожный покров бледно-серый, холодный, следы термического повреждения по типу соприкосновения с металлом различной локализации на шее, волосистой части головы, передней поверхности грудной клетки, брюшной стенке, в паховой области, на левой стопе. Госпитализирована в ОРИТ, начат комплекс мер диагностики и интенсивной терапии. Выявлены декомпенсированный метаболический ацидоз, биохимические признаки повреждения миокарда и мышечной ткани. Назначены инфузионная терапия, анальгетики, антибиотики, блокаторы протонной помпы, антикоагулянты. На фоне проводимого лечения в первые 6 часов явления шока купированы, через 4 суток в стабильном состоянии переведена в травматологическое отделение. После перевода из ОРИТ сохраняются нарушения слуха, боль и нарушения чувствительности в левой стопе.Заключение. Необходим комплексный подход в диагностике, лечении, реабилитации пациентов с поражением атмосферным электричеством

Gluon Shadowing in DIS off Nuclei

Within a light-cone quantum-chromodynamics dipole formalism based on the Green function technique, we study nuclear shadowing in deep-inelastic scattering at small Bjorken xB < 0.01. Such a formalism incorporates naturally color transparency and coherence length effects. Calculations of the nuclear shadowing for the \bar{q}q Fock component of the photon are based on an exact numerical solution of the evolution equation for the Green function, using a realistic form of the dipole cross section and nuclear density function. Such an exact numerical solution is unavoidable for xB > 0.0001, when a variation of the transverse size of the \bar{q}q Fock component must be taken into account. The eikonal approximation, used so far in most other models, can be applied only at high energies, when xB < 0.0001 and the transverse size of the \bar{q}q Fock component is "frozen" during propagation through the nuclear matter. At xB < 0.01 we find quite a large contribution of gluon suppression to nuclear shadowing, as a shadowing correction for the higher Fock states containing gluons. Numerical results for nuclear shadowing are compared with the available data from the E665 and NMC collaborations. Nuclear shadowing is also predicted at very small xB corresponding to LHC kinematical range. Finally the model predictions are compared and discussed with the results obtained from other models.Comment: 29 pages including 7 figures; Fig.7 modified, some references and corresponding discussion adde

Stimulated emission of radiation using spin-population inversion in metals: a spin-laser

Arrays of 10 nm-diameter point contacts of exchange-coupled spin-majority/spin-minority ferromagnetic metals, integrated into infrared-terahertz range photon resonators, are fabricated and measured electrically and optically. Giant, threshold-type electronic excitations under high-current pumping of the devices are observed as abrupt but reversible steps in device resistance, in many cases in access of 100%, which correlate with optical emission from the devices. The results are interpreted as due to stimulated spin-flip electron-photon relaxation in the system.Comment: 5 page