Physics Letters A 329 (2004) 14–21 www.elsevier.com/locate/pla Manifestations of wave packet revivals in the moments of observables C. Sudheesh, S. Lakshmibala ∗ , V. Balakrishnan Department of Physics, Indian Institute of Technology Madras, Chennai 600 036, India Received 5 May 2004; accepted 28 June 2004 Available online 10 July 2004 Communicated by P.R. Holland Abstract Using a generic Hamiltonian that models wave packet propagation in a Kerr-like medium, matter wave field dynamics in Bose–Einstein condensation, etc., we show that distinctive signatures of wave packet revivals and fractional revivals are dis- played by the time evolution of the expectation values of appropriate observables, enabling selective identification of different fractional revivals.  2004 Elsevier B.V. All rights reserved. PACS: 03.65.-w; 42.50.-p; 42.50.Md; 42.50.Dv Keywords: Coherent states; Wave packet revival; Fractional revivals; Expectation values Quantum wave packet dynamics governed by a nonlinear Hamiltonian can display a variety of non- classical effects [1–3], arising from the interference between the stationary states comprising the wave packet. These effects manifest themselves through several observable phenomena such as revivals, frac- tional revivals and super-revivals of the wave packet at specific instants of time. The revival phenomenon * Corresponding author. E-mail addresses: sudheesh@chaos.iitm.ernet.in (C. Sudheesh), slbala@chaos.iitm.ernet.in (S. Lakshmibala), vbalki@chaos.iitm.ernet.in (V. Balakrishnan). has been observed experimentally and investigated theoretically [4–21] in a wide class of suitably pre- pared states subject to specific nonlinear potentials, in- cluding Rydberg wave packets, molecular vibrational states, Bose–Einstein condensates (BECs), etc. The non-classical effects that arise in the dynamics of spe- cific wave packets evolving in a Kerr medium [22], collapse and revival phenomena displayed by a single- mode field propagating in a nonlinear medium [23], and the temporal behavior of a macroscopic super- position of coherent states governed by a nonlinear Hamiltonian [24] have been reported upon. An inter- esting analogy between revivals of wave packets and 0375-9601/$ – see front matter  2004 Elsevier B.V. All rights reserved. doi:10.1016/j.physleta.2004.06.085