# Time-saving steps

A widely used method to study nuclear dynamics in heavy-ion scattering, fusion and fission phenomena, and giant-resonances in nuclei is time-dependent Hartree-Fock (TDHF) calculations, which assume that the wave function of the system consists of time-evolving occupied orbitals. Time-dependent Hartree-Fock-Bogoliubov (TDHFB) calculations go a step further, in that they include pairing interactions between particles, but the calculations require a much larger set of quasiparticle orbits. This makes the calculations almost prohibitively time consuming and has so far blocked progress in treating the problem of nuclear superfluidity.

Writing in *Physical Review C*, Shuichiro Ebata and colleagues at the RIKEN Nishina Center, Wako, and the University of Tsukuba, both in Japan, have formulated TDHFB in the so-called canonical basis. By making certain approximations, they develop a set of equations that can be solved on a three-dimensional mesh in a time comparable to TDHF calculations. The authors make a successful test of their calculation scheme for the response of a nucleus to an electromagnetic probe, namely, the isovector-dipole and isoscalar-quadrupole strength distributions in isotopes of neon and magnesium. (This is possible because the small-amplitude limit of TDHFB is identical to the quasiparticle-random-phase-approximation (QRPA), for which the authors have already developed calculation codes.) A possible application of the method, namely, to yield a fully microscopic treatment of fission, could provide a real breakthrough in nuclear physics research. – *John Millener*