Bond-order wave phase, spin solitons and thermodynamics of a frustrated linear spin-1/2 Heisenberg antiferromagnet

The linear spin-1/2 Heisenberg antiferromagnet with exchanges $J_1$, $J_2$ between first and second neighbors has a bond-order wave (BOW) phase that starts at the fluid-dimer transition at $J_2/J_1 = 0.2411$ and is particularly simple at $J_2/J_1 = 1/2$. The BOW phase has a doubly degenerate singlet ground state, broken inversion symmetry and a finite energy gap $E_m$ to the lowest triplet state. The interval $0.4<J_2/J_1<1.0$ has large $E_m$ and small finite size corrections. Exact solutions are presented up to $N=28$ spins with either periodic or open boundary conditions and for thermodynamics up to $N=18$. The elementary excitations of the BOW phase with large $E_m$ are topological spin-1/2 solitons that separate BOWs with opposite phase in a regular array of spins. The molar spin susceptibility $\chi_M(T)$ is exponentially small for $T \ll E_m$ and increases nearly linearly with $T$ to a broad maximum. $J_1$, $J_2$ spin chains approximate the magnetic properties of the BOW phase of Hubbard-type models and provide a starting point for modeling alkali-TCNQ salts.Comment: 10 pages, 12 figure

IMPACTS OF EURO ADOPTION ON BANKS IN THE NEW MEMBER STATES

Banking systems of the NMS are strongly linked to those of the EU15 Member States. Accession of NMS to EMU will likely to act, in the medium to long term, as a catalyst to strengthen already existing developments and trends in the banking systems of these countries. Accession to EMU will likely to strengthen the pressure for the reduction of existing excess capacity in the banking sector of the NMS. Further on, it is expected to put profitability under pressure and lead to increased geographical diversification and internationalisation, as well as to increased conglomeration and mergers and acquisitions. Overall, competition in banking within the euro area is likely to increase considerably after the NMS join EMU. When assessing any potential outcomes or challenges arising from the EMU presence of NMS banks, banks shall automatically take part in an adjustment process where, ideally, they redefine their roles and restructure, if necessary, their strategies for participation in an enlarged euro area market. In the preparation stage, banks in the NMS shall increase their awareness of challenges EMU can bring and here experiences of the present EMU Member States can be a major asset. In theory, changeover to the euro in NMS might represent a risk in the banking systems (revenue and cost implications of the transition to the euro). in the medium term, the negative effects of the structural adjustment process in the EU banking systems could be concentrated in strategically unfavourably placed banks that may not cope with the risks and difficulties associated with the adaptation to that process. Nevertheless, in the longer term, the adjustment process should result in a stronger and fitter banking sector and generate customer gains due to increased competition. In addition, the transition to a stable monetary environment should bring positive effects to the banking systems in the NMS. This shall be mostly felt by those banking industries that previously operated in a relatively high inflationary environment.banking sector, EMU, new member states, Financial Economics,

Diversity and Polarization of Research Performance: Evidence from Hungary

Measuring the intellectual diversity encoded in publication records as a proxy to the degree of interdisciplinarity has recently received considerable attention in the science mapping community. The present paper draws upon the use of the Stirling index as a diversity measure applied to a network model (customized science map) of research profiles, proposed by several authors. A modified version of the index is used and compared with the previous versions on a sample data set in order to rank top Hungarian research organizations (HROs) according to their research performance diversity. Results, unexpected in several respects, show that the modified index is a candidate for measuring the degree of polarization of a research profile. The study also points towards a possible typology of publication portfolios that instantiate different types of diversity

Marginal Intra-Industry Trade and Adjustment Costs - A Hungarian-Polish Comparison

The structure of trade expansion in Hungary and Poland over the period 1990-1998 and its implications for labour-market adjustment is examined. An econometric analysis of trade and employment data suggests that changes in domestic consumption and productivity have significant influence on employment changes. But our results do not provide support for the smooth-adjustment hypothesis of intra-industry trade.Intra-industry trade, adjustment costs