Generality of excitation suppression by impulsive plane waves

Determine whether the suppressing effect of impulsive plane waves on Unruh–DeWitt detector excitation is a general rule or occurs only for particular values of the wave-strength parameter η.

Background

The paper uses a non-perturbative open quantum system treatment to calculate the response of a harmonic-oscillator Unruh–DeWitt detector interacting with a massless scalar field in impulsive plane wave spacetimes. It studies two specific geometries: a Ricci-flat impulsive gravitational wave and a null electromagnetic wave. In both cases, the authors find that the wave suppresses the detector’s transition probability from the ground state to the first excited state.

The unresolved issue is whether this suppression persists for arbitrary values of the impulsive-wave strength η and, more broadly, whether it represents a universal feature of impulsive plane wave backgrounds rather than a property of the particular examples analyzed.

References

Indeed, one possible extension of our work is to investigate whether this is a general rule or if it holds only for particular values of η.

— Open quantum system approach to the Unruh-DeWitt detector in impulsive plane wave spacetimes  (2608.19692 - Cho, 20 Aug 2026) in Section V, Conclusions and discussions

Therefore, in future work, we can consider a more general u_i to investigate how conjugate planes affect the quantum state of the detector, particularly its transition probabilities to excited states.

— Open quantum system approach to the Unruh-DeWitt detector in impulsive plane wave spacetimes  (2608.19692 - Cho, 20 Aug 2026) in Section V, Conclusions and discussions