Anomalous population of 10^{10}He states in reactions with 11^{11}Li

Structure with the lowest energy observed in the $^{10}$He spectrum populated in the proton knockout reaction with $^{11}$Li beam has a peak at $1.2-1.5$ MeV. This peak is usually interpreted as a resonant $0^+$ ground state of $^{10}$He. Our theoretical calculations indicate that this peak is likely to be a pileup of $1^-$, $0^+$, and $2^+$ excitations with very similar shapes. %We predict a very specific nature of the $1^-$ excitation in $^{10}$He. Moreover, the ``soft'' $1^-$ excitation appears to be the lowest one in energy. Such an anomalous continuum response is traced to the halo structure of $^{11}$Li providing extreme low energy shift to all the expected continuum excitations. Competitions of the initial state structure (ISS) and the final state interaction (FSI) effects on the spectrum and three-body correlations in $^{10}$He are discussed. Analogous effect of the extreme low-energy shift could also be expected in other cases of $2n$ emitters populated in reactions with halo nuclei. Simplified example of the $^{10}$He spectrum in $\alpha$ knockout from $^{14}$Be, is given. We also discuss limits on the properties of $^{9}$He stemming from the observed $^{10}$He spectrum.Comment: 10 pages, 13 figure

Pauli-principle driven correlations in four-neutron nuclear decays

Mechanism of simultaneous non-sequential four-neutron ($4n$) emission (or `true' $4n$-decay) has been considered in phenomenological five-body approach. This approach is analogous to the model of the direct decay to the continuum often applied to $2n$- and $2p$-decays. It is demonstrated that $4n$-decay fragments should have specific energy and angular correlations reflecting strong spatial correlations of `valence' nucleons orbiting in their $4n$-precursors. Due to the Pauli exclusion principle, the valence neutrons are pushed to the symmetry-allowed configurations in the $4n$-precursor structure, which causes a `Pauli focusing' effect. Prospects of the observation of the Pauli focusing have been considered for the $4n$-precursors $^7$H and $^{28}$O. Fingerprints of their nuclear structure or/and decay dynamics are predicted

Mechanics and Mathematical Modeling of Class III Treatment with Orthodontic Appliances with a Movable Ramp

Treatment of class III is a current problem in orthodontics that requires constant improvement of its methods, development of new or modifications of known methods and techniques. We have developed and studied the modification of removable functionally-directing orthodontic appliances for treatment of Class III, which consists of a plastic base, vestibular arc, retaining clasps, ramp, which is connected with the base by means of two torsion springs. Its usage ensures a prolonged contact of ramp with the teeth. We studied two types of club-shaped springs (torsion springs): one spring, which create an amortization effect during the action of the ramp, but do not change its inclination angle and second one – spring that seek to increase the angle of the ramp inclination due to the disclosure of its curl

Analytical solution of the optimal laser control problem in two-level systems

The optimal control of two-level systems by time-dependent laser fields is studied using a variational theory. We obtain, for the first time, general analytical expressions for the optimal pulse shapes leading to global maximization or minimization of different physical quantities. We present solutions which reproduce and improve previous numerical results.Comment: 12 pages, 2 figure

The main directions for pharmacological correction (combinations of drugs for general anesthesia) of neurological and cognitive disorders in patients with neoplasms of the central nervous system

The aim of the study was to develop a goal-oriented combination of drugs for general anesthesia, based on a retrospective assessment of the baseline level of neurological and cognitive disorders in adults and children at the stage of preparation for surgery for neoplasms of the central nervous system (sub- and supratentorial neoplasms - SubTNN and SupraTNN), and a prospective evaluation of complications in the postoperative perio

Universal Dynamic Conductivity and Quantized Visible Opacity of Suspended Graphene

We show that the optical transparency of suspended graphene is defined by the fine structure constant, alpha, the parameter that describes coupling between light and relativistic electrons and is traditionally associated with quantum electrodynamics rather than condensed matter physics. Despite being only one atom thick, graphene is found to absorb a significant (pi times alpha=2.3%) fraction of incident white light, which is a consequence of graphene's unique electronic structure. This value translates into universal dynamic conductivity G =e^2/4h_bar within a few percent accuracy

Topological photonics with scattering media

Scattering media, being ubiquitous in nature and critically important for assessments (e.g., biological tissues), are often considered as nuisance in optics. Here we show that it is not always the case and scattering media could be essential in providing elements of topological photonics. We demonstrate that topological darkness can be realised in the presence of scattering media due to the transverse nature of electromagnetic waves and the hairy ball theorem. We describe realizations of topological darkness in a scattering medium comprising composite gold nanostructures produced by a low-cost technique of laser structuring of thin metal films. Our results can be useful for a variety of tasks, including topological nanophotonics, optical label-free biosensing, and biomedical photonics