We extend the notion of basic classes (for the Donaldson invariants) to 4-manifolds with b > 1 which are (potentially) not of simple type or satisfy b1 > 0. We also give a structure theorem for the Donaldson invariants of 4-manifolds with b > 1, b1 > 0 and of strong simple type.

The prototypical magnetic memory shape alloy Ni_{2}MnGa undergoes various phase transitions as a function of the temperature, pressure, and doping. In the low-temperature phases below 260 K, an incommensurate structural modulation occurs along the [110] direction which is thought to arise from the softening of a phonon mode. It is not at present clear how this phenomenon is related, if at all, ...

Optical control of spin is of central importance in the research of ultrafast spintronic devices utilizing spin dynamics at short time scales. Recently developed optical approaches such as ultrafast demagnetization, spin-transfer and spin-orbit torques open new pathways to manipulate spin through its interaction with photon, orbit, charge or phonon. However, these processes are limited by eithe...

Demagnetization in a thin film due to terahertz pulse of magnetic field is investigated. Linearized Landau-Lifshitz-Gilbert (LLG) equation the Fourier space describe magnetization dynamics derived, and spin wave time evolution studied. Finally, demagnetization recent experimental observations on similar system compared. As result, marginal role loss established.