Topological self-organization of strongly interacting particles

We investigate the self-organization of strongly interacting particles confined in 1D and 2D. We consider hardcore bosons in spinless Hubbard lattice models with short-range interactions. We show that many-body states with topological features emerge at different energy bands separated by large gaps. The topology manifests in the way the particles organize in real space to form states with different energy. Each of these states contains topological defects/condensations whose Euler characteristic can be used as a topological number to categorize states belonging to the same energy band. We provide analytical formulas for this topological number and the full energy spectrum of the system for both sparsely and densely filled systems. Furthermore, we analyze the connection with the Gauss-Bonnet theorem of differential geometry, by using the curvature generated in real space by the particle structures. Our result is a demonstration of how states with topological characteristics, emerge in strongly interacting many-body systems following simple underlying rules, without considering the spin, long-range microscopic interactions, or external fields.Comment: 6 pages, 1 figure, some revisions, published in EPJ

Neuronal Correlation Parameter in the Idea of Thermodynamic Entropy of an N-Body Gravitationally Bounded System

Understanding how the brain encodes information and performs computation requires statistical and functional analysis. Given the complexity of the human brain, simple methods that facilitate the interpretation of statistical correlations among different brain regions can be very useful. In this report we introduce a numerical correlation measure that may serve the interpretation of correlational neuronal data, and may assist in the evaluation of different brain states. The description of the dynamical brain system, through a global numerical measure may indicate the presence of an action principle which may facilitate a application of physics principles in the study of the human brain and cognition

Yukawa Potential Orbital Energy: Its Relation to Orbital Mean Motion as well to the Graviton Mediating the Interaction in Celestial Bodies

Research on gravitational theories involves several contemporary modified models that predict the existence of a non-Newtonian Yukawa-type correction to the classical gravitational potential. In this paper we consider a Yukawa potential and we calculate the time rate of change of the orbital energy as a function of the orbital mean motion for circular and elliptical orbits. In both cases we find that there is a logarithmic dependence of the orbital energy on the mean motion. Using that, we derive an expression for the mean motion as a function of the Yukawa orbital energy, as well as specific Yukawa potential parameters. Furthermore, various special cases are examined. Lastly, expressions for the Yukawa range and coupling constant are also derived. Finally, an expression for the mass of the graviton mediating the interaction is calculated using the expression its Compton wavelength (i.e., the potential range ).Numerical estimates for the mass of the graviton mediating the interaction are finally obtained at various eccentricity values and in particular at the perihelion and aphelion points of Mercury’s orbit around the sun

Economic uncertainty and cardiovascular disease mortality

Previous studies have found a link between economic conditions, such as recessions and unemployment, and cardiovascular disease as well as other health outcomes. More recent research argues that economic uncertainty—independently of unemployment—can affect health outcomes. Using data from England and Wales, we study the association between fluctuations in economic uncertainty and cardiovascular disease mortality in the short term for the period 2001–2019. Controlling for several economic indicators (including unemployment), we find that economic uncertainty alone is strongly associated with deaths attributed to diseases of the circulatory system, ischemic heart disease and cerebrovascular disease. Our findings highlight the short-term link between economic conditions and cardiovascular health and reveal yet another health outcome that is associated with uncertainty

Essays on inequalities in health and health care during economic recessions

During the past decade, Greece faced an unprecedented economic crisis and signed an economic adjustment programme (EAP) that brought about changes and reforms to the Greek health system. Comprised of three empirical studies, this thesis focuses on the impact of the Greek crisis on the health sector, with a particular interest in the responses to and implications of the crisis across socioeconomic groups. The first paper studies how household spending behaviour and responses towards health care have changed across socioeconomic groups in the face of an economic shock and the relevant health policy measures. Our analysis suggests that the income elasticity of household health expenditure (HHE) is below unity and exhibits a significant increase after the introduction of the EAP. Thus, households exhibit greater health care consumption responses to changes in their income. Contrary to high socioeconomic status (SES) groups, lower SES households did not become more sensitive to income changes in the post-EAP period, and have been more “protective” about their health care consumption. Focusing on the older population, the second study concentrates on the potential changes and implications in terms of financial protection against health payments during the Greek recession. We find that the headcount and overshoot of catastrophic health expenditure (CHE) increased during the crisis, with low-income and households with multimorbid patients being disproportionately affected. Prior to the crisis, CHE was mainly due to inpatient and nursing care. During the recession, however, the contribution of pharmaceutical spending to CHE substantially increased. Our analysis also reveals that there are widening inequalities in the risk of CHE across socioeconomic groups after the onset of the crisis. The third paper mainly focuses on population health status. It studies how economic climate and uncertainty influence fertility decisions and responses across population groups, and further investigates whether economic conditions during pregnancy impact newborn health. Our findings generally suggest that birth weight and pregnancy length are procyclical. We also report heterogeneity in the relationship between economic conditions during pregnancy and newborn health across socioeconomic groups, with the birth outcomes of high-SES newborns being responsive to economic volatility only in the first trimester of pregnancy. Further, economic adversity during the preconception period increases the probability that women who conceive are highly educated and married. After accounting for selection, we find that newborns exposed to the crisis while in utero tend to be lighter, with the effect being more detrimental for low-SES children

The Poynting–Robertson Effect in the Newtonian Potential with a Yukawa Correction

We consider a Yukawa-type gravitational potential combined with the Poynting-Robertson effect. Dust particles originating within the asteroid belt and moving on circular and elliptic trajectories are studied and expressions for the time rate of change of their orbital radii and semimajor axes, respectively, are obtained. These expressions are written in terms of basic particle parameters, namely their density and diameter. Then, they are applied to produce expressions for the time required by the dust particles to reach the orbit of Earth. For the Yukawa gravitational potential, dust particles of diameter 10-3 m in circular orbits require times of the order of 8.557 x 106 y and for elliptic orbits of eccentricities e = 0.1, 0.5 require times of 9.396 x 106 and 2.129 x 106 y respectively to reach Earth\u27s orbit. Finally, various cases of the Yukawa potential are studied and the corresponding particle times to reach Earth\u27s are derived per case along with numerical results for circular and various elliptical orbits

Coherent wave transmission in quasi-one-dimensional systems with L\'evy disorder

We study the random fluctuations of the transmission in disordered quasi-one-dimensional systems such as disordered waveguides and/or quantum wires whose random configurations of disorder are characterized by density distributions with a long tail known as L\'evy distributions. The presence of L\'evy disorder leads to large fluctuations of the transmission and anomalous localization, in relation to the standard exponential localization (Anderson localization). We calculate the complete distribution of the transmission fluctuations for different number of transmission channels in the presence and absence of time-reversal symmetry. Significant differences in the transmission statistics between disordered systems with Anderson and anomalous localizations are revealed. The theoretical predictions are independently confirmed by tight binding numerical simulations.Comment: 10 pages, 6 figure