ABSTRACT
We theoretically study an impulsively excited quantum bouncer (QB)-a particle bouncing off a surface in the presence of gravity. A pair of time-delayed pulsed excitations is shown to induce a wave-packet echo effect-a partial rephasing of the QB wave function appearing at twice the delay between pulses. In addition, an appropriately chosen observable [here, the population of the ground gravitational quantum state (GQS)] recorded as a function of the delay is shown to contain the transition frequencies between the GQSs, their populations, and partial phase information about the wave-packet quantum amplitudes. The wave-packet echo effect is a promising candidate method for precision studies of GQSs of ultracold neutrons, atoms, and antiatoms confined in closed gravitational traps.
ABSTRACT
We propose a novel scheme for efficient Raman sub-harmonic generation in a system of inhomogeneously broadened atomic vapor with atoms in a closed three-level Λ-configuration. The key feature underlying Raman sub-harmonics generation is microwave-induced hyperfine coherence between the two lower level metastable states. We show explicitly how the amplitude and phase of the microwave field generate controllable spectral amplitudes of Raman sub-harmonics. Our scheme is viable in currently available atomic vapor cells thereby opening the way for efficient sub-harmonic generation in standard experimental setups.
