Two-body correlation functions in nuclear matter with npnp condensate

The density, spin and isospin correlation functions in nuclear matter with a neutron-proton ($np$) condensate are calculated to study the possible signatures of the BEC-BCS crossover in the low-density region. It is shown that the criterion of the crossover (Phys. Rev. Lett. {\bf 95}, 090402 (2005)), consisting in the change of the sign of the density correlation function at low momentum transfer, fails to describe correctly the density-driven BEC-BCS transition at finite isospin asymmetry or finite temperature. As an unambiguous signature of the BEC-BCS transition, there can be used the presence (BCS regime) or absence (BEC regime) of the singularity in the momentum distribution of the quasiparticle density of states.Comment: Prepared with RevTeX4, 5p., 4 figure

ANI-1, A data set of 20 million calculated off-equilibrium conformations for organic molecules

One of the grand challenges in modern theoretical chemistry is designing and implementing approximations that expedite ab initio methods without loss of accuracy. Machine learning (ML) methods are emerging as a powerful approach to constructing various forms of transferable atomistic potentials. They have been successfully applied in a variety of applications in chemistry, biology, catalysis, and solid-state physics. However, these models are heavily dependent on the quality and quantity of data used in their fitting. Fitting highly flexible ML potentials, such as neural networks, comes at a cost: a vast amount of reference data is required to properly train these models. We address this need by providing access to a large computational DFT database, which consists of more than 20 M off equilibrium conformations for 57,462 small organic molecules. We believe it will become a new standard benchmark for comparison of current and future methods in the ML potential community

Spontaneous breaking of rotational symmetry in superconductors

We show that homogeneous superconductors with broken spin/isospin symmetry lower their energy via a transition to a novel superconducting state where the Fermi-surfaces are deformed to a quasi-ellipsoidal form at zero total momentum of Cooper pairs. In this state, the gain in the condensation energy of the pairs dominates over the loss in the kinetic energy caused by the lowest order (quadrupole) deformation of Fermi-surfaces from the spherically symmetric form. There are two energy minima in general, corresponding to the deformations of the Fermi-spheres into either prolate or oblate forms. The phase transition from spherically symmetric state to the superconducting state with broken rotational symmetry is of the first order.Comment: 5 pages, including 3 figures, published versio

Competition of ferromagnetic and antiferromagnetic spin ordering in nuclear matter

In the framework of a Fermi liquid theory it is considered the possibility of ferromagnetic and antiferromagnetic phase transitions in symmetric nuclear matter with Skyrme effective interaction. The zero temperature dependence of ferromagnetic and antiferromagnetic spin polarization parameters as functions of density is found for SkM$^*$, SGII effective forces. It is shown that in the density domain, where both type of solutions of self--consistent equations exist, ferromagnetic spin state is more preferable than antiferromagnetic one.Comment: 9p., 3 figure

The AFLOW Fleet for Materials Discovery

The traditional paradigm for materials discovery has been recently expanded to incorporate substantial data driven research. With the intent to accelerate the development and the deployment of new technologies, the AFLOW Fleet for computational materials design automates high-throughput first principles calculations, and provides tools for data verification and dissemination for a broad community of users. AFLOW incorporates different computational modules to robustly determine thermodynamic stability, electronic band structures, vibrational dispersions, thermo-mechanical properties and more. The AFLOW data repository is publicly accessible online at aflow.org, with more than 1.7 million materials entries and a panoply of queryable computed properties. Tools to programmatically search and process the data, as well as to perform online machine learning predictions, are also available.Comment: 14 pages, 8 figure

Оценка эффективности оперативного лечения больных с хронической критической ишемией нижних конечностей в стадии трофических осложнений

Relevance. Chronic critical ischemia of the lower extremities (CCILE) in the stage of trophic complications is the final stage of diseases of the arteries of the lower extremities, leading to disability of patients and having a poor prognosis in terms of preservation of the lower extremities and mortality.Aim of study. Objective assessment of the efficacy of lower limb revascularization in trophic disorders.Material and methods. The analysis of treatment of 52 patients with stage IV CCILE (according to the classification of R. Fontaine and A.V. Pokrovsky) was carried out. Of these, 42 patients underwent three-phase scintigraphy combined with X-ray computed angiography on a hybrid apparatus. After the operation, this study was conducted in 37 patients.Results. Out of 52 patients, surgery for revascularization of the lower extremities was performed in 37 patients, 15 were not operated on. Out of 37 operated patients, improvement of blood circulation occurred in 32 (86.5%). Circulatory decompensation was observed in 5 patients (9.7%). Among non-operated patients, improvement of blood circulation occurred in 9 patients (17.3%), no effect or decompensation — in 5 (9.7%). Subjective improvement in the condition and decrease in the degree of ischemia corresponded to the improvement of microcirculation according to the data of three-phase scintigraphy.Conclusion.1. Revascularization of the lower extremities in patients with trophic disorders is an effective method of treating this pathology. Therefore, all patients with chronic ischemia threatening limb loss should be considered as candidates for revascularization.2. If the leg arteries or short occlusive or stenotic lesions of the main arteries are affected, such patients should be discussed together with specialists in endovascular surgery for endovascular treatment or joint intervention.3. Hybrid radiation method (three-phase scintigraphy and single-photon emission computed tomography, combined with X-ray computed angiography) is an objective method that reflects the state of peripheral circulation and microcirculation, and allows you to objectively assess the effectiveness of the treatment.Актуальность. Хроническая критическая ишемия нижних конечностей (ХКИНК) в стадии трофических осложнений представляет собой конечную стадию заболеваний артерий нижних конечностей, приводящую к инвалидизации больных и имеющую неблагоприятный прогноз по показателям сохранения нижних конечностей и летальности.Цель исследования. Объективная оценка эффективности реваскуляризации нижних конечностей при трофических расстройствах.Материал и методы. Проведен анализ лечения 52 больных ХКИНК IV стадии (по классификации R. Fontaine и А.В. Покровского). Из них 42 пациентам выполнена трехфазная сцинтиграфия, совмещенная с рентгеновской компьютерной ангиографией на гибридном аппарате. После операции данное исследование проведено 37 пациентам.Результаты. Из 52 пациентов операция по реваскуляризации нижних конечностей выполнена 37 пациентам, не оперированы 15. Из 37 оперированных улучшение кровообращения произошло у 32 (86,5%). Декомпенсация кровообращения отмечена у 5 пациентов (9,7%). Среди неоперированных пациентов улучшение кровообращения произошло у 9 пациентов (17,3%), отсутствие эффекта или декомпенсация — у 5 (9,7%). Субъективное улучшение состояния и снижение степени ишемии соответствовали улучшению микроциркуляции по данным трехфазной сцинтиграфии.Выводы.1. Реваскуляризация нижних конечностей у пациентов с трофическими нарушениями является эффективным методом лечения данной патологии. Поэтому все пациенты с хронической ишемией, угрожающей потерей конечности, должны быть рассмотрены как кандидаты для реваскуляризации.2. При поражении артерий голени или коротких окклюдирующих или стенотических поражениях магистральных артерий такие пациенты должны быть обсуждены совместно со специалистами по рентгенэндоваскулярной хирургии на предмет эндоваскулярного лечения или выполнения вмешательства совместно.3. Гибридный лучевой метод (трехфазная сцинтиграфия и однофотонная эмиссионная компьютерная томография, совмещенная с рентгеновской компьютерной ангиографией) является объективным методом, отображающим состояние периферического кровообращения и микроциркуляции, и позволяет объективно оценить эффективность проведенного лечения