M&A in the Construction Industry -Wealth Effects of Diversification into Real Estate Life Cycle Related Services

Since the late 1990s, the construction industry has undergone a change in business model, as contractors vertically expand their operations to other parts of the real estate life cycle. The question arises on whether construction companies have superior abilities as real estate service providers. We have examined the value implications of 106 large merger and acquisition (M&A) transactions in the construction industry worldwide from 1986 to 2006. We inquire if a vertical expansion of the construction value chain in the real estate life cycle through M&A leads to the creation of shareholder value. We find out that this is not the case. M&A success is mainly determined by industry-specific size effects and common agency conflicts.Construction industry; Cross-border acquisitions; Bidder gains; Global diversification

Measuring excitation-energy transfer with a real-time time-dependent density functional theory approach

We investigate the time an electronic excitation travels in a supermolecular setup using a measurement process in an open quantum-system framework. The approach is based on the stochastic Schr\"odinger equation and uses a Hamiltonian from time-dependent density functional theory (TDDFT). It treats electronic-structure properties and intermolecular coupling on the level of TDDFT, while it opens a route to the description of dissipation and relaxation via a bath operator that couples to the dipole moment of the density. Within our study, we find that in supermolecular setups small deviations of the electronic structure from the perfectly resonant case have only minor influence on the pathways of excitation-energy transfer, thus lead to similar transfer times. Yet, sizable defects cause notable slowdown of the energy spread

Topological Superconductivity in Skyrmion Lattices

Atomic manipulation and interface engineering techniques have provided a novel approach to custom-designing topological superconductors and the ensuing Majorana zero modes, representing a new paradigm for the realization of topological quantum computing and topology-based devices. Magnet-superconductor hybrid (MSH) systems have proven to be experimentally suitable to engineer topological superconductivity through the control of both the complex structure of its magnetic layer and the interface properties of the superconducting surface. Here, we demonstrate that two-dimensional MSH systems containing a magnetic skyrmion lattice provide an unprecedented ability to control the emergence of topological phases. By changing the skyrmion radius, which can be achieved experimentally through an external magnetic field, one can tune between different topological superconducting phases, allowing one to explore their unique properties and the transitions between them. In these MSH systems, Josephson scanning tunneling spectroscopy spatially visualizes one of the most crucial aspects underlying the emergence of topological superconductivity, the spatial structure of the induced spin-triplet correlations

Neutrino-driven winds in the aftermath of a neutron star merger: nucleosynthesis and electromagnetic transients

We present a comprehensive nucleosynthesis study of the neutrino-driven wind in the aftermath of a binary neutron star merger. Our focus is the initial remnant phase when a massive central neutron star is present. Using tracers from a recent hydrodynamical simulation, we determine total masses and integrated abundances to characterize the composition of unbound matter. We find that the nucleosynthetic yields depend sensitively on both the life time of the massive neutron star and the polar angle. Matter in excess of up to $9 \cdot 10^{-3} M_\odot$ becomes unbound until $\sim 200~{\rm ms}$. Due to electron fractions of $Y_{\rm e} \approx 0.2 - 0.4$ mainly nuclei with mass numbers $A < 130$ are synthesized, complementing the yields from the earlier dynamic ejecta. Mixing scenarios with these two types of ejecta can explain the abundance pattern in r-process enriched metal-poor stars. Additionally, we calculate heating rates for the decay of the freshly produced radioactive isotopes. The resulting light curve peaks in the blue band after about $4~{\rm h}$. Furthermore, high opacities due to heavy r-process nuclei in the dynamic ejecta lead to a second peak in the infrared after $3-4~{\rm d}$.Comment: 15 pages, 18 figures, 2 tables, accepted by Ap