Vision of nuclear physics with photo-nuclear reactions by laser-driven γ beams

A laser-accelerated dense electron sheet with an energy E = (gamma) over tilde mc(2) can be used as a relativistic mirror to coherently reflect a second laser with photon energy h omega, thus generating by the Doppler boost [A. Einstein, Annalen der Physik 17, 891 (1905); D. Habs et al., Appl. Phys. B 93, 349 (2008)] brilliant high-energy photon beams with h omega' = 4 (gamma) over tilde (2)h omega. and short duration for many new nuclear physics experiments. While the shortest-lived atomic levels are in the atto-second range, nuclear levels can have lifetimes down to zeptoseconds. We discuss how the modulation of electron energies in phase-locked laser fields used for as-measurements [E. Goulielmakis et al., Science 317, 769 (2007)] can be carried over to the new direct measurement of fs-zs nuclear lifetimes by modulating the energies of accompanying conversion electrons or emitted protons. In the field of nuclear spectroscopy we discuss the new perspective as a function of increasing photon energy. In nuclear systems a much higher sensitivity is predicted to the time variation of fundamental constants compared to atomic systems [V. Flambaum, arXiv:nucl-th/0801.1994v1 (2008)]. For energies up to 50 keV Mossbauer-like recoilless absorption allows to produce nuclear bosonic ensembles with many delocalized coherent polaritons [G. V. Smirnov et al., Phys. Rev. A 71, 023804 (2005)] for the first time. Using the (gamma, n) reaction to produce cold, polarized neutrons with a focusing ellipsoidal device [P. Boni, Nucl. Instrum. Meth. A 586, 1 (2008); Ch. Schanzer et al., Nucl. Instrum. Meth. 529, 63 (2004)], brilliant cold polarized micro-neutron beams become available. The compact and relatively cheap lasergenerated. beams may serve for extended studies at university-based facilities.