Casimir attraction in multilayered plane parallel magnetodielectric systems

A powerful procedure is presented for calculating the Casimir attraction between plane parallel multilayers made up of homogeneous regions with arbitrary magnetic and dielectric properties by use of the Minkowski energy-momentum tensor. The theory is applied to numerous geometries and shown to reproduce a number of results obtained by other authors. Although the various pieces of theory drawn upon are well known, the relative ease with which the Casimir force density in even complex planar structures may be calculated, appears not to be widely appreciated, and no single paper to the author's knowledge renders explicitly the procedure demonstrated herein. Results may be seen as an important building block in the settling of issues of fundamental interest, such as the long-standing dispute over the thermal behaviour of the Casimir force or the question of what is the correct stress tensor to apply, a discussion re-quickened by the newly suggested alternative theory due to Raabe and Welsch.Comment: 13 pages, 6 figures. Version 2: Updated contact details. Minor changes and correction

Surface Enhanced van der Waals force

We consider the van der Waals interaction of an excited atom and a ground state atom across a vacuum-medium interface under the circumstances of the resonant coupling of the excited atom to a surface polariton mode of the system. We demonstrate that the nonretarded interaction potential between the atoms is in this case the same as in an effective medium described by the average dielectric function of the media in contact except for the different local-field correction factor. The estimate performed for the vacuum-sapphire interface shows that the nonretarded van der Waals (atom*-atom) force can be at the surface mode resonance enhanced by almost three orders of magnitude in comparison with its free-space value. Owing to the local-field effect in the present configuration this enhancement factor is larger then previously estimated for atoms in front of the same medium by (almost) an order of magnitude.Comment: 6 pages, 2 figures; presented at CEWQO08, Belgrade, Serbia, 30 May-03 June 200

Casimir force between dispersive magnetodielectrics

We extend our approach to the Casimir effect between absorbing dielectric multilayers [M. S. Tomas, Phys. Rev. A 66, 052103 (2002)] to magnetodielectric systems. The resulting expression for the force is used to numerically explore the effect of the medium dispersion on the attractive/repulsive force in a metal-magnetodielectric system described by the Drude-Lorentz permittivities and permeabilities.Comment: 12 pages, 5 eps figures, revised, accepted for publication in Phys. Lett.

Medium-modified Casimir forces

We argue that the results for the vacuum forces on a slab and on an atom embedded in a magnetodielectric medium near a mirror, obtained using a recently suggested Lorentz-force approach to the Casimir effect, are equivalent to the corresponding results obtained in a traditional way. We also derive a general expression for the atom-atom force in a medium and extend a few classical results concerning this force in vacuum and dielectrics to magnetodielectric systems. This, for example, reveals that the (repulsive) interaction between atoms of different polarizability type is at small distances unaffected by a (weakly polarizable) medium.Comment: 5 pages, 1 figure, reinterpreted and revise

BOOK REVIEW: NIKOLA NJEGOVAN (2022) FRIEDMAN’S CHALLENGE

Book Review: Nikola Njegovan. (2022). Friedman’s Challenge. Belgrade: Faculty of Economics University of Belgrade, Centre for Publishing, 207 pages

„Bernardinų“ fondo reikšmė tiriant istoriografinius naratyvus apie Armijos Krajovos Kmicico brigadą

During World War II, in 1939–1944, there was a Polish armed resistance movement in Eastern Lithuania, which was called Armia Krajowa (Home Army) in the abstract. In researching the activities of Armia Krajowa (AK) in Eastern Lithuania, not only historiography is valuable, but also surviving documents and memoirs, as well as the Bernardine Fund preserved in the Lithuanian Central State Archives. So far, this Fund does not seem to receive much attention from scientists researching the activities of AK in Lithuania, as well as archives compiled by Poles residing in other countries. Based on the concept of storage medium, the article analyzes the case of the Bernardine Fund in the context of archival research of the Polish diaspora. During the analysis of the documents kept in the Bernardine Fund, it was observed that the said Fund held significant documents that could supplement / replace the existing narrative about Kmicic’s AK partisan brigade. Kmicic’s AK partisan brigade is noteworthy, as it is the first armed AK unit to launch a consistent armed resistance, but so far there are no separate studies dedicated to the activities of this brigade. The storage medium is the basis of memory communication that gives authenticity to the constructed memory narrative. The Bernardine Fund is a storage medium that originated in the past and reached the present unchanged / slightly changed, and that contains a certain memory narrative about AK. The Bernardine Fund and the documents contained in it are valuable storage media that can help reveal the situation of the residents of Eastern Lithuania during World War II and shed new light on the military activities of AK. In the context of research and preservation of the written heritage of the Polish diaspora, this medium has not yet received the attention of scientists, although the example of the Kmicic’s AK brigade proved that this Fund contains documents that reveal hitherto unknown aspects of AK activities. A fact turns into an event only when certain groups draw their attention to it, when they give meaning to it and start talking and writing about it, and it begins to be remembered. All significant events are just someone’s creations, created just to justify the present in a way that is convenient for the collective, the political elite, or the heads of state. The case of Kmicic’s brigade has proven that no fact is completely lost. If a fact is not currently updated and used, it does not mean that it will be the case all the time. The documents kept in the Fund reflect that during the formation of the historiographical narrative, the collective memory of the said brigade, part of the events was deliberately omitted in order to give integrity to the narrative being formed.Antrojo pasaulinio karo metais (1939–1944 m.) Rytų Lietuvoje veikė lenkų ginkluotas pasipriešinimo judėjimas, kurį abstrahuojant priimta vadinti Armija Krajova. Tyrinėjant Armijos Krajovos veiklą Rytų Lietuvoje vertinga yra ne tik istoriografija, bet taip pat ir išlikę dokumentai, atsiminimai bei Lietuvos centriniame valstybės archyve saugomas „Bernardinų“ fondas. Šis fondas kol kas, atrodo, nesulaukia daug dėmesio iš mokslininkų, tiriančių AK veiklą Lietuvoje, taip pat kaupiančių lenkų, gyvenusių kitose valstybėse, archyvus. Remiantis atminties laikmenos konceptu, straipsnyje analizuojamas „Bernardinų“ fondo atvejis lenkų išeivijos archyvinių tyrimų kontekste. Atliekant „Bernardinų“ fonde saugomų dokumentų analizę, pastebėta, kad minėtame fonde yra reikšmingų dokumentų, kurie galėtų papildyti / pakeisti esamą naratyvą apie AK Kmicico partizaninę brigadą. AK Kmicico partizaninė brigada verta dėmesio, nes tai yra pirmas ginkluotas AK dalinys, kuris pradėjo nuoseklų ginkluotą pasipriešinimą, bet kol kas nėra atskirų tyrimų, skirtų šios brigados veiklai. Atminties laikmena – tai atminties komunikacijos pagrindas, suteikiantis konstruojamam atminties naratyvui autentiškumo. „Bernardinų“ fondas – tai atminties laikmena, kuri atsirado praeityje ir nepakitusi / menkai pakitusi pasiekė dabartį ir kuri savyje saugo tam tikrą atminties naratyvą apie AK. „Bernardinų“ fondas ir jame esantys dokumentai – tai vertingos atminties laikmenos, kurios gali padėti atskleisti Rytų Lietuvos gyventojų padėtį Antrojo pasaulinio karo metu, naujai nušviesti karinę AK veiklą. Lenkų išeivijos rašytinio paveldo tyrimų ir išsaugojimo kontekste ši laikmena kol kas nesulaukia mokslininkų dėmesio, nors AK Kmicico brigados pavyzdys įrodė, kad šiame fonde yra dokumentų, kurie atskleidžia iki šiol nežinomus AK veiklos aspektus. Faktas tampa įvykiu tik tuomet, kai tam tikros grupės atkreipia į jį dėmesį, kai suteikia jam reikšmę ir pradeda apie jį kalbėti, rašyti ir jis pradedamas atsiminti. Visi reikšmingi įvykiai tėra kažkieno kūriniai, sukurti tik tam, kad galėtų pagrįsti dabartį taip, kaip tai yra patogu kolektyvui, politiniam elitui arba valstybių vadovams. Kmicico brigados atvejis parodė, kad joks faktas nėra visiškai prarandamas. Jeigu faktas šiuo metu nėra aktualizuotas, naudojamas, tai nereiškia, jog taip bus visą laiką. Fonde saugomi dokumentai rodo, kad formuojant istoriografinį naratyvą, kolektyvinę atmintį apie minėtą brigadą dalis įvykių buvo sąmoningai nutylėti siekiant formuojamam naratyvui suteikti vientisumo

A stochastic forecast for the Croatian pension system

This paper analyses the financial sustainability of the Croatian pension system after the reform that was adopted on January 1, 2019. The Croatian pension system as we know it today was started in 1999 with a reform that created the three pillars of the pension system. Over the next twenty years, Croatian economic and social conditions shifted in an unexpected way and a new reform was needed to ensure financial stability is maintained. In this paper I will analyse population trends in Croatia and forecast movements up to 2060. Afterwards, I will analyse the net government cash flow generated from the pension system, by using the forecast population numbers. The beginning year of the forecast horizon is 2018, as some data were not yet available for this year. I use stochastic methods to perform my analysis

Imidazolium-Based Ionic Liquids: Some Research Methods, Applications and Physico-Chemical Properties

Imidazolium-based ionic liquids (ILs) represent a well-studied class of ILs. These compounds are characterized by many fascinating properties such as non-flammability, low vapor pressure, wide electrochemical window, and thermodynamic and kinetic stability. This review paper aims to provide an insight into some experimental methods of investigations and applications of these ILs. Additionally, some results on the topic of imidazolium-based ILs in various solvents are presented. This work is licensed under a Creative Commons Attribution 4.0 International License