Impulsively Excited Gravitational Quantum States: Echoes and Time-resolved Spectroscopy

TL;DR

This paper proposes a theoretical method using wave-packet echoes and time-resolved spectroscopy to study gravitational quantum states, enabling precise measurements of transition frequencies and quantum amplitudes.

Contribution

It introduces a novel wave-packet echo technique for impulsively excited gravitational quantum states, facilitating detailed quantum state analysis.

Findings

Wave-packet echo effect observed at twice the pulse delay

Observable reveals transition frequencies and state populations

Method applicable to ultra-cold neutrons, atoms, and anti-atoms

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 ultra-cold neutrons, atoms, and anti-atoms confined in closed gravitational traps.