Generalization of Bloch's theorem for arbitrary boundary conditions: Interfaces and topological surface band structure

We describe a method for exactly diagonalizing clean $D$-dimensional lattice systems of independent fermions subject to arbitrary boundary conditions in one direction, as well as systems composed of two bulks meeting at a planar interface. Our method builds on the generalized Bloch theorem [A. Alase et al., Phys. Rev. B 96, 195133 (2017)] and the fact that the bulk-boundary separation of the Schrodinger equation is compatible with a partial Fourier transform operation. Bulk equations may display unusual features because they are relative eigenvalue problems for non-Hermitian, bulk-projected Hamiltonians. Nonetheless, they admit a rich symmetry analysis that can simplify considerably the structure of energy eigenstates, often allowing a solution in fully analytical form. We illustrate our extension of the generalized Bloch theorem to multicomponent systems by determining the exact Andreev bound states for a simple SNS junction. We then analyze the Creutz ladder model, by way of a conceptual bridge from one to higher dimensions. Upon introducing a new Gaussian duality transformation that maps the Creutz ladder to a system of two Majorana chains, we show how the model provides a first example of a short-range chiral topological insulator hosting topological zero modes with a power-law profile. Additional applications include the complete analytical diagonalization of graphene ribbons with both zigzag-bearded and armchair boundary conditions, and the analytical determination of the edge modes in a chiral $p+ip$ two-dimensional topological superconductor. Lastly, we revisit the phenomenon of Majorana flat bands and anomalous bulk-boundary correspondence in a two-band gapless $s$-wave topological superconductor. We analyze the equilibrium Josephson response of the system, showing how the presence of Majorana flat bands implies a substantial enhancement in the $4\pi$-periodic supercurrent.Comment: 20+9 pages, 10 figure

IL-36γ has proinflammatory effects on human endothelial cells

Interleukin-36 cytokines are predominantly expressed by epithelial cells. Significant upregulation of epidermal IL-36 is now a recognised characteristic of psoriatic skin inflammation. IL-36 is known to induce inflammatory responses in dendritic cells, fibroblasts and epithelial cells. Although vascular alterations are a hallmark of psoriatic lesions and dermal endothelial cells are well known to play a critical role in skin inflammation, the effects of IL-36 on endothelial cells are unexplored. We here show that endothelial cells including dermal microvascular cells express a functionally active IL-36 receptor. Adhesion molecules VCAM-1 and ICAM-1 are upregulated by IL-36γ stimulation and this is reversed by the presence of the endogenous IL-36 receptor antagonist. IL-36γ stimulated endothelial cells secrete the proinflammatory chemokines IL-8, CCL2 and CCL20. Chemotaxis assays showed increased migration of T cells following IL-36γ stimulation of endothelial cells. These results suggest a role for IL-36γ in the dermal vascular compartment and it is likely to enhance psoriatic skin inflammation by activating endothelial cells and promoting leukocyte recruitment. This article is protected by copyright. All rights reserved

The Interpretative Phenomenological Analysis (IPA): A Guide to a Good Qualitative Research Approach

As a research methodology, qualitative research method infuses an added advantage to the exploratory capability that researchers need to explore and investigate their research studies. Qualitative methodology allows researchers to advance and apply their interpersonal and subjectivity skills to their research exploratory processes. However, in a study with an interpretative phenomenological analysis (IPA) approach, the advantageous elements of the study quadruple because of the bonding relationship that the approach allows for the researchers to develop with their research participants. Furthermore, as a qualitative research approach, IPA gives researchers the best opportunity to understand the innermost deliberation of the ‘lived experiences’ of research participants. As an approach that is ‘participant-oriented’, interpretative phenomenological analysis approach allows the interviewees (research participants) to express themselves and their ‘lived experience’ stories the way they see fit without any distortion and/or prosecution. Therefore, utilizing the IPA approach in a qualitative research study reiterates the fact that its main objective and essence are to explore the ‘lived experiences’ of the research participants and allow them to narrate the research findings through their ‘lived experiences’. As such, this paper discusses the historical background of phenomenology as both a theory and a qualitative research approach, an approach that has transitioned into an interpretative analytical tradition. Furthermore, as a resource tool to novice qualitative researchers, this paper provides a step-by-step comprehensive guide to help prepare and equip researchers with ways to utilize and apply the IPA approach in their qualitative research studies.  More importantly, this paper also provides an advanced in-depth analysis and usability application for the IPA approach in a qualitatively conducted research study. As such, this paper completely contrasted itself from many books and articles that are written with the premise of providing useful and in-depth information on the subject-matter (phenomenology, as a qualitative approach)

THE TASKS OF REVIEWING AND FINDING THE RIGHT ORGANIZATIONAL CHANGE THEORY

Organizational change is probably the singular most important undertaken that many organizations wish they could do to affect their productivities/profitability performances.  This review paper will highlight some of the well-known theories and approaches to organizational change.  In the late 1990s and early 2000s, America had one of the best economies in decades and many of her citizens were able to benefit from it both financially and educationally; the economy (and educational aspirations) grew expeditiously and lifted millions of Americans out of poverty.  These economical and educational turnarounds were achieved due in part to innovative and transformational leaders who understand that in order for businesses to grow, organizational change has to be an integral part of the process.  However, the issue now is that there seems to be too many complex and confusing change theories that profess to have the remedies for ‘fixing’ the organizational problems.  Ideally, however, this review paper will try to highlight the essentials of the selected organizational change and leadership theories and simplify them by making them accessible and understandable.  Additionally, this review will try to ease some of the confusions of the theories and potentially help guide the change agents to the appropriate organizational change theories. 

The Evolution of Education in Nigeria: How has it Impacted Ordinary Nigerians from Pre-Independence till Present?

This article looked at the maturity of the Nigerian educational system from independence until now.  As a comprehensive and historical review of the educational system/standard in Nigeria, this article examine some of the educational issues/shortcomings confronting the Nigerian people, and their inability to anticipate and strategically plan a course of action to handle the stressors.  Additionally, this article also discussed the effects of globalization and how it has transformed/reshaped the fundamentalism of educational practices in Africa.  As such, the problem with the Nigerian educational system is that it is lacking in many educational areas.  It is recommended that the Nigerian government facilitate the development/construction of new infrastructures.  For any society to grow/function properly, economically, developmentally, and/or fundamentally it needs certain infrastructures in place, i.e., standardized and structurally sound school buildings

The matrix permanent and determinant from a spin system

In contrast to the determinant, no algorithm is known for the exact determination of the permanent of a square matrix that runs in time polynomial in its dimension. Consequently, non interacting fermions are classically efficiently simulatable while non-interacting bosons are not, underpinning quantum supremacy arguments for sampling the output distribution of photon interferometer arrays. This work introduces a graph-theoretic framework that bridges both the determinant and permanent. The only non-zero eigenvalues of a sparse non-Hermitian operator $\breve{M}$ for $n$ spin-$1/2$ particles are the $n$th roots of the permanent or determinant of an $n\times n$ matrix $M$, interpreting basis states as bosonic or fermionic occupation states, respectively. This operator can be used to design a simple and straightforward method for the classical determination of the permanent that matches the efficiency of the best-known algorithm. Gauss-Jordan elimination for the determinant of $M$ is then equivalent to the successive removal of the generalized zero eigenspace of the fermionic $\breve{M}$, equivalent to the deletion of some nodes and reweighting of the remaining edges in the graph such that only $n$ nodes survive after the last step. In the bosonic case, the successive removal of generalized zero eigenspaces for $\breve{M}$ is also equivalent to node deletion, but new edges are added during this process, which gives rise to the higher complexity of computing the permanent. Our analysis may point the way to new strategies for classical and quantum evaluation of the permanent

Observing a Changing Hilbert-Space Inner Product

In quantum mechanics, physical states are represented by rays in Hilbert space $\mathscr H$, which is a vector space imbued by an inner product $\langle\,|\,\rangle$, whose physical meaning arises as the overlap $\langle\phi|\psi\rangle$ for $|\psi\rangle$ a pure state (description of preparation) and $\langle\phi|$ a projective measurement. However, current quantum theory does not formally address the consequences of a changing inner product during the interval between preparation and measurement. We establish a theoretical framework for such a changing inner product, which we show is consistent with standard quantum mechanics. Furthermore, we show that this change is described by a quantum channel, which is tomographically observable, and we elucidate how our result is strongly related to the exploding topic of PT-symmetric quantum mechanics. We explain how to realize experimentally a changing inner product for a qubit in terms of a qutrit protocol with a unitary channel.Comment: 12 pages, 4 figures, updated version includes an erratu

Reply to the Comment on `The operational foundations of PT-symmetric and quasi-Hermitian quantum theory'

This document is our reply to the Comment arXiv:2301.01215 on our recent work titled `The operational foundations of PT-symmetric and quasi-Hermitian quantum theory'. The original Comment consists of three addenda to our work. The first addendum claims that our work is ill-motivated as the motivating question, namely whether PT-symmetric quantum theory extends the standard quantum theory, was already answered in the literature. The second addendum points to some missing references in our work, and the third addendum suggests what constraints could lead to an extension of standard quantum theory. In our reply, we explain that the claim in the first addendum is a result of a misinterpretation of our motivating question. When interpreted correctly, the third addendum in the Comment in itself elaborates on why our motivating question is interesting and relevant. We also briefly comment on the prospects of an extension of standard quantum theory along the lines suggested in the third addendum. As our response to the second addendum, we explain our rationale behind citing certain references while leaving out others.Comment: 5 pages, reply to arXiv:2301.0121

Just-In-Time Inventory Management Practice and Performance of Selected Polytechnics in Southwest, Nigeria: Implications for Sustainable Stock Efficiency

This study examined Just-in-Time (JIT) inventory management practice and performance of selected polytechnics in Southwest Nigeria, and the implications for sustaining stock efficiency. The study used descriptive survey research design and a total of one thousand and thirty-six (1,036) store employees from federal, state and private polytechnics in the Southwest, Nigeria. A sample size of five hundred and forty-four (544) determined through multi-stage and stratified sampling technique was used for data analysis. Primary data were obtained through questionnaire while linear regression was employed to determine the effects and statistical significance of the relationships between the study variables. The Statistical Package for Social Sciences (SPSS) version 24.0 was applied to process the data and the hypothesis was tested at p-value of = 0.05 level of significance while descriptive statistical analysis was used to identify frequencies and percentages. The findings of the study showed that JIT inventory management practice cannot be underestimated in determining performance of polytechnics in Southwest Nigeria. The study recommended that management of polytechnics in Southwest Nigeria should develop a policy framework to facilitate faster implementation of the best inventory management practices such as JIT as it has proven to have significant positive effect on employees’ performance