Skowronek has commented on a Rayleigh-scattering cross-section measurement for various pulse durations made by us. His comments are discussed, and his questions on our experimental methods are answered.
In the preceding Comment, the authors suggest that the molecular conversion efficiency in atom-molecule stimulated Raman adiabatic passage can be improved by lowering the initial atomic density, which in turn requires longer pulse durations to maintain adiabaticity. Apart from the fact that the mean-field approximation becomes questionable at low densities, we point out that a low-density strategy with longer pulses has several problems. It generally requires higher pulse energies and increases radiative losses. We also show that even within the approximations used in the Comment, their example leads to no efficiency improvement compared to our high-density case. In a more careful analysis including radiative losses neglected in the Comment, the proposed strategy gives almost no conversion owing to the longer pulse durations required.
Nonadiabatic dynamics of neutral atoms in nonuniform magnetic fields, typical of quadrupole magnetic traps, has been considered in my earlier paper [V. I. Yukalov, Phys. Rev. A 56, 5004 (1997)]. The main result of this paper is that an unusual semiconfining regime of motion was found, when atoms are confined from one side of an axis, but are not confined from another side. The author of the Comment [V. E. Shapiro, Phys. Rev. A 60, 719 (1999)] expressed doubts on the validity of this result, advancing several concrete questions. In the present reply I answer all of these questions and show that they do not invalidate the possibility of realizing the semiconfining regime of motion.
In the note by Khemani et al. [arXiv:2001.11037] the authors express conceptual disagreement with our recent paper on quantum time crystals [Phys. Rev. Lett. 123, 210602]. They criticise the idealized nature of the considered quantum time crystal, and make several points about properties of Hamiltonians presented in our work. In this reply we answer one-by-one all questions raised in the discussion. As for the ideological dispute, it brightly highlights a bizarre nature of time crystalline order in closed quantum systems, and we offer a different vision for the development of the field.