Incommensurate and multiple-q\boldsymbol{q} magnetic misfit order in the frustrated quantum spin ladder material antlerite, Cu3_3SO4_4(OH)4_4

In frustrated magnetic systems, the competition amongst interactions can introduce extremely high degeneracy and prevent the system from readily selecting a unique ground state. In such cases, the magnetic order is often exquisitely sensitive to the balance among the interactions, allowing tuning among novel magnetically ordered phases. In antlerite, Cu$_3$SO$_4$(OH)$_4$, Cu$^{2+}$ ($S=1/2$) quantum spins populate three-leg zigzag ladders in a highly frustrated quasi-one-dimensional structural motif. We demonstrate that at zero applied field, in addition to its recently reported low-temperature phase of coupled ferromagnetic and antiferromagnetic spin chains, this mineral hosts an incommensurate helical+cycloidal state, an idle-spin state, and a multiple-$q$ phase which is the magnetic analog of misfit crystal structures. The antiferromagnetic order on the central leg is reentrant. The high tunability of the magnetism in antlerite makes it a particularly promising platform for pursuing exotic magnetic order.Comment: 18.3 pages, 16 Figures, follow-up paper to arXiv:2203.1534

Pressure-induced dimerization and valence bond crystal formation in the Kitaev-Heisenberg magnet alpha-RuCl3

Magnetization and high-resolution x-ray diffraction measurements of the Kitaev-Heisenberg material alpha-RuCl3 reveal a pressure-induced crystallographic and magnetic phase transition at a hydrostatic pressure of p=0.2 GPa. This structural transition into a triclinic phase is characterized by a very strong dimerization of the Ru-Ru bonds, accompanied by a collapse of the magnetic susceptibility. Ab initio quantum-chemistry calculations disclose a pressure-induced enhancement of the direct 4d-4d bonding on particular Ru-Ru links, causing a sharp increase of the antiferromagnetic exchange interactions. These combined experimental and computational data show that the Kitaev spin liquid phase in alpha-RuCl3 strongly competes with the crystallization of spin singlets into a valence bond solid

Manganites at Quarter Filling: Role of Jahn-Teller Interactions

We have analyzed different correlation functions in a realistic spin-orbital model for half-doped manganites. Using a finite-temperature diagonalization technique the CE phase was found in the charge-ordered phase in the case of small antiferromagnetic interactions between $t_{2g}$ electrons. It is shown that a key ingredient responsible for stabilization of the CE-type spin and orbital-ordered state is the cooperative Jahn-Teller (JT) interaction between next-nearest Mn$^{+3}$ neighbors mediated by the breathing mode distortion of Mn$^{+4}$ octahedra and displacements of Mn$^{+4}$ ions. The topological phase factor in the Mn-Mn hopping leading to gap formation in one-dimensional models for the CE phase as well as the nearest neighbor JT coupling are not able to produce the zigzag chains typical for the CE phase in our model.Comment: 16 pages with 16 figures, contains a more detailed parameter estimate based on the structural data by Radaelli et al. (accepted for publication in Phys. Rev. B

Can a single model explain both breast cancer and prostate cancer?

<p>Abstract</p> <p>Background</p> <p>The Estradiol-Dihydrotestosterone model of prostate cancer (PC) showed how the interaction of hormones with specific hormone receptors affected apoptosis. The same hormone can produce different effects, depending on which hormone receptor it interacts with.</p> <p>Model</p> <p>This model proposes that the first step in the development of most PC and breast cancer (BC) occurs when aromatase converts testosterone to estradiol (E2). A sufficiently high enough local level of E2 results in telomerase activity. The telomerase activity allows cell division and may lead to BC or PC, which will proliferate if the rate of cell division is greater than the rate of cell death. The effect of hormones on their hormone receptors will affect the rate of cell death and determine whether or not the cancer proliferates.</p> <p>Conclusion</p> <p>By minimizing bcl-2 and maximizing apoptotic proteins, new systemic treatments for BC and PC can be developed that may be more effective than existing treatments.</p

On the nature of «cultural shift» in the value system of the creative class in a prosperous society

Исследована природа креативного класса, основания и предпосылки «культурного сдвига» в пространстве ценностного мира креативного класса. Проанализированы условия и тенденции формирования системы постматериалистических ценностей (самовыражение, благополучие, счастье), характерных для системы ценностного мира, креативного класса. Раскрыта роль инноваций как креативного разрушения. Заявлена идея возможности измерения креативности в условиях, основанных на знаниях и инновациях экономического роста. В статье анализируется природа «смещения» − «тектонических сдвигов», произошедших в сегментах власти и управления на пороге XXI в. Установлена приоритетная роль знания в обозначенных трансформациях как статуса доминирующего ресурса когнитивного общества. Представлена идея формирования «интеллектуальной элиты» когнитивного общества; признаки элитарности формируются как определяемые владением знанием. Показано, что в границах институтов, связанных с интеллектуальной деятельностью, «новой элите» принадлежит монополия на власть и управление. Однако в мире большой политики можно говорить лишь о влиянии «новой элиты» в сегментах экспертизы, консалтинге, процедуре анализа технически сложных решений.The article examines the nature of the creative class, the foundations and prerequisites for the «cultural shift» in the space of the value world of the creative class. The authors have analyzed the preconditions and tendencies of the formation of a system of post-materialistic values - the values of self-expression, well-being, happiness - which are characteristic for the system of the value world, the creative class. The role of innovation as a creative destruction is revealed. The idea of the possibility of measuring creativity in the context of knowledge-based and innovation-based economic growth is announced. The article analyzes the nature of the «displacement» - «tectonic shifts» that occurred in the segments of power and management on the threshold of the XXI century. The authors revealed the priority role of knowledge in the indicated transformations as the status of the dominant resource of the cognitive society. The paper introduces the idea of forming an «intellectual elite» of a cognitive society; signs of elitism are formed as determined by the possession of knowledge. It is shown that within the boundaries of institutions related to intellectual activity, the «new elite» has a monopoly on power and control. But in the world of big politics, one can only talk about the influence of the «new elite» in the areas of expertise, consulting, and procedures for analyzing technically complex decisions