Effect of local Coulomb interaction on Majorana corner modes: weak and strong correlation limits

Here we present an analysis of the evolution of Majorana corner modes realizing in a higher-order topological superconductor (HOTSC) on a square lattice under the influence of local Coulomb repulsion. The HOTSC spectral properties were considered in two regimes: when the intensities of many-body interactions are either weak or strong. The weak regime was studied using the mean-field approximation with self-consistent solutions carried out both in the uniform case and taking into account of the boundary of the finite square-shaped system. It is shown that in the uniform case the topologically nontrivial phase on the phase diagram is widened by the Coulomb repulsion. The boundary effect, resulting in an inhomogeneous spatial distribution of the correlators, leads to the appearance of the crossover from the symmetric spin-independent solution to the spin-dependent one characterized by a spontaneously broken symmetry. In the former the corner states have energies that are determined by the overlap of the excitation wave functions localized at the different corners. In the latter the corner excitation energy is defined by the Coulomb repulsion intensity with a quadratic law. The crossover is a finite size effect, i.e. the larger the system the lesser the critical value of the Coulomb repulsion. In the strong repulsion regime we derive the effective HOTSC Hamiltonian in the atomic representation and found a rich variety of interactions induced by virtual processes between the lower and upper Hubbard subbands. It is shown that Majorana corner modes still can be realized in the limit of the infinite repulsion. Although the boundaries of the topologically nontrivial phase are strongly renormalized by Hubbard corrections.Comment: 13 pages, 6 figure

A generic C1C^1 map has no absolutely continuous invariant probability measure

Let $M$ be a smooth compact manifold (maybe with boundary, maybe disconnected) of any dimension $d \ge 1$. We consider the set of $C^1$ maps $f:M\to M$ which have no absolutely continuous (with respect to Lebesgue) invariant probability measure. We show that this is a residual (dense $G_\delta) set in the$C^1$ topology. In the course of the proof, we need a generalization of the usual Rokhlin tower lemma to non-invariant measures. That result may be of independent interest.Comment: 12 page

Dispersion of sound velocity in certain organic liquids /

Prepared for the National Science Foundation Russian Science Translation-Dictionary Project, Columbia University, July, 1953--page 5.Translated from Doklady Akademii Nauk SSSR, 92, 285-88 (1953)--title page."February 1954."Includes bibliographical references (page 4).Mode of access: Internet

Анализ симметрии радиальных профилей магнитных скирмионов

The search for analytical profiles of chiral magnetic structures such as 2D magnetic skyrmions (MS) is important for their theoretical study. Since the Euler–Lagrange (EL) equations for such excita- tions are not solved exactly, the MSs are described using analytical ansatzs. In this work, we validate one of the widely used ansatzs based on a symmetry analysis of the 1D analog of the EL equations, which characterizes the radial profile of the MS. As a development of this approach, a profiles of skyrmion bags are proposedПоиск аналитических профилей киральных магнитных структур типа 2D магнитных скирмионов (МС) является важным при их теоретическом описании. Поскольку уравнения Эйлера–Лагранжа (ЭЛ) для таких возбуждений не решаются точно, описание МС проводят с помощью аналитических пробных функций — анзацев. В настоящей работе проводится обоснование одного из широко используемых анзацей на основе симметрийного анализа 1D версии уравнений ЭЛ, определяющего радиальный профиль МС. В развитии такого подхода предлагаются профили скирмионных мешков с топологическими зарядами Q >