Electron momentum distribution of a single mobile hole in the t-J model

We investigate the electron momentum distribution function (EMDF) for the two-dimensional t-J model. The results are based on the self-consistent Born approximation (SCBA) for the self-energy and the wave function. In the Ising limit of the model we give the results in a closed form, in the Heisenberg limit the results are obtained numerically. An anomalous momentum dependence of EMDF is found and the anomaly is in the lowest order in number of magnons expressed analitycally. We interpret the anomaly as a fingerprint of an emerging large Fermi surface coexisting with hole pockets.Comment: M2S - submitted to Physica

Geometrical view of quantum entanglement

Although a precise description of microscopic physical problems requires a full quantum mechanical treatment, physical quantities are generally discussed in terms of classical variables. One exception is quantum entanglement which apparently has no classical counterpart. We demonstrate here how quantum entanglement may be within the de Broglie-Bohm interpretation of quantum mechanics visualized in geometrical terms, giving new insight into this mysterious phenomenon and a language to describe it. On the basis of our analysis of the dynamics of a pair of qubits, quantum entanglement is linked to concurrent motion of angular momenta in the Bohmian space of hidden variables and to the average angle between these momenta

NOMEN EST OMEN: MEDICINSKA I FARMACEUTSKA ZANIMANJA U SLOVENSKIM PREZIMENIMA

The heritage of Slovenian house names and surnames reflects, among others, the former medicine and pharmaceutical occupations, midwifery, and folk medicine practices, and besides that, also health status and illnesses of people. Surnames, which are especially strongly intertwined with family, local and social history, are closely related to folk medicine and magic. Unlike house names (vulgo), which are the usual nicknames for physical and mental characteristics and abilities, surnames denote medical occupations and medicinal folk practice as such. According to the most recent data (as of January 1, 2020) of The Statistical Office of the Republic of Slovenia, at least 40 surnames reminiscent former medical or pharmaceutical professions. These newly discovered digital data in open access are precious for the history of medicine because they allow comparing surnames geographically, by frequency, and through the time.Baština slovenskih kućnih imena i prezimena odražava, među ostalim, nekadašnja medicinska i farmaceutska zanimanja, primaljske te narodne medicinske prakse, a uz to i zdravstveno stanje te bolesti ljudi. Prezimena, koja su posebno snažno isprepletena s obiteljskom, lokalnom i društvenom poviješću, usko su povezana s narodnom medicinom i magijom. Za razliku od kućnih imena (vulgo), koja su uobičajeno nadimci za fizičke i mentalne karakteristike i sposobnosti, prezimena označavaju medicinska zanimanja i medicinsku narodnu praksu kao takvu. Prema najnovijim podacima (od 1. siječnja 2020.) Zavoda za statistiku Republike Slovenije, najmanje četrdeset prezimena podsjeća na bivše medicinske ili farmaceutske profesije. Ovi svima dostupni digitalni podaci dragocjeni su za povijest medicine jer omogućuju usporedbu prezimena geografski, po učestalosti i kroz vrijeme

Etika v evropskih raziskavah

Glavna razlika med 7. OP / FP7 (7. okvirni program za raziskave in tehnološki razvoj / Seventh Framework Programme, 2007–2013) v primerjavi s 6. OP / FP6 (6. okvirni program za raziskave in tehnološki razvoj / Sixth Framework Programme, 2002–2006) je v tem, da morajo projekti, ki so bodisi usmerjeni v krepitev znanstveno-tehnološke podlage industrije, projekti, ki spodbujajo mednarodno konkurenčnost ter raziskave, ki podpirajo politiko Evropske unije, vsebovati tudi natančen opis o etiki raziskovalnega dela. Presojevalci ga ocenijo, ko je že dosežena ocena znanstvene primernosti. Eno od desetih znanstvenih področij, kamor sodijo etnološke, antropološke in folkloristične raziskave, so t. i. družbeno-ekonomske in humanistične vede, in tudi za to področje velja, da so lahko financirane samo raziskave, ki imajo jasno izdelana etična načela, ki upoštevajo nacionalne zakone, mednarodne protokole, konvencije in listine ter dobijo privolitev nacionalnih etičnih komisij. Vse to pa pomeni, da morajo tudi humanistične discipline jasno oblikovati in premisliti etična načela, vanje vključiti sodobne pravne norme, da sploh smejo upati na sredstva, namenjena za raziskave, podprte s sredstvi Evropske komisije. *** The main difference between FP7 (Seventh Framework Programme, 2007-2013) and FP6 (Sixth Framework Programme, 2002-2006) is in ethical dimension of project evaluation. All projects in FP7 that enhance international concurrence, scientific and technological growth of industry and all projects, which support the EU policy, must be carried out in compliance with fundamental ethical principles. The ethics of research is part of scientific evaluation of the project. Socio-economic sciences and Humanities is one of the ten scientific fields, where we find ethnology, anthropology and folklore, and where the financing is possible if the research proposals include clear ethical principles, consideration of national acts, international protocols, conventions, charters and if they get the approval of national ethics commissions. All these mean that Humanities must clearly form and reflect ethical principles and include modern legal norms in their applications if they want to be funded from the institutions of European Commission

Conductance of a molecule with a center of mass motion

We calculate the zero temperature conductance and characteristic correlation functions of a molecule with a center of mass (CM) motion which modulates couplings to the leads. In the first model studied, the CM vibrational mode is simultaneously coupled to the electron density on the molecule. The conductance is suppressed in regimes corresponding to non-integer occupancy of the molecule. In the second model, where the CM mode is not directly coupled to the electron density, the suppression of conductance is related to the dynamic breaking of the inversion symmetry.Comment: to appear in Phys. Rev.

Medicinski rasizam

The article analyses key examples of unethical medical experimentation on humans. The first part deals with racism, its ideology, and connectedness with concepts of medical racism. Concepts of the race that first emerged during the colonial expansion were defined by following their origins and function and not the philosophical thought. The second part builds upon the autonomy of patients. It includes the right to informed consent, protection of privacy, right of confidence, and persons with limited autonomy, all from a historical perspective on medical racism. In this section, the selected cases of medical racism show that the development of legal regulations and ethical norms importantly influenced the medical practice and the protection of subjects. The historical evidence also witnesses that even if the formal protection existed, there were deviations from it. The deviations were closely related to socio-political regulation and the rapid development of medicine that was a step before ethical norms. Additionally, war crimes against humanity were connected with personal ideological orientations of doctors whose racist, discriminatory beliefs were far beyond medical ethics and the purpose of medical practice. In the end, the article deals with the questions whether the results from unethical and unscientific experiments should be used and in what way medical racism endangers vulnerable groups today.U radu su analizirani ključni primjeri neetičkog medicinskog eksperimentiranja na ljudima. Prvi dio se bavi rasizmom, njegovom ideologijom i povezanošću s pojmovima medicinskog rasizma. Koncepti rase koji su se prvi put pojavili tijekom kolonijalne ekspanzije definirani su slijedeći njihovo podrijetlo i funkciju, a ne filozofsku misao. Drugi dio govori o autonomiji pacijenata. To uključuje pravo na informirani pristanak, zaštitu privatnosti, pravo na povjerenje i probleme osoba s ograničenom autonomijom, a sve iz povijesne perspektive na medicinski rasizam. U ovom su dijelu odabrani slučajevi medicinskog rasizma pokazali da je razvoj zakonskih propisa i etičkih normi značajno utjecao na medicinsku praksu i zaštitu ispitanika. Povijesni dokazi svjedoče da je, čak i ako je postojala formalna zaštita, bilo odstupanja od nje. Odstupanja su bila usko povezana s društveno-političkom regulacijom i brzim razvojem medicine koji je bio korak ispred etičkih normi. Uz to, ratni zločini protiv čovječnosti bili su povezani s osobnim ideološkim orijentacijama liječnika čija su rasistička, diskriminirajuća uvjerenja bila daleko od medicinske etike i svrhe medicinske prakse. Na kraju se rad bavi pitanjima trebaju li se koristiti rezultati neetičkih i neznanstvenih eksperimenata i kako medicinski rasizam ugrožava ranjive skupine danas

Biennial conference of the European Association for the History of Medicine and Health: “Crisis in Health and Medicine”

Scientific meeting review / Prikaz skup

Kondo effect in triple quantum dots

Numerical analysis of the simplest odd-numbered system of coupled quantum dots reveals an interplay between magnetic ordering, charge fluctuations and the tendency of itinerant electrons in the leads to screen magnetic moments. The transition from local-moment to molecular-orbital behavior is visible in the evolution of correlation functions as the inter-dot coupling is increased. Resulting novel Kondo phases are presented in a phase diagram which can be sampled by measuring the zero-bias conductance. We discuss the origin of the even-odd effects by comparing with the double quantum dot.Comment: 4 pages, 4 figure

Spin-fluctuation mechanism of superconductivity in cuprates

The theory of superconductivity within the t-J model, as relevant for cuprates, is developed. It is based on the equations of motion for projected fermionic operators and the mode-coupling approximation for the self-energy matrix. The dynamical spin susceptibility at various doping is considered as an input, extracted from experiments. The analysis shows that the superconductivity onset is dominated by the spin-fluctuation contribution. We show that T_c is limited by the spin-fluctuation scale $\Gamma$ and shows a pronounced dependence on the next-nearest-neighbor hopping t'. The latter can offer an explanation for the variation of T_c among different families of cuprates.Comment: Color figure