Isolated vibrational wavepackets in D2+: Defining superposition conditions and wavepacket distinguishability

TL;DR

This study investigates vibrational wavepackets in D2+ ions created by ultrafast laser pulses, analyzing their dynamics and conditions for quantum coherence, with implications for quantum computation using molecular systems.

Contribution

It defines conditions for creating and distinguishing vibrational wavepackets in D2+ and explores their potential for quantum information processing.

Findings

Isolated vibrational wavepackets can be characterized and their evolution quantified.

Requirements for initial coherence and state retrieval are identified for quantum computing applications.

Temporal control of pump and probe pulses influences wavepacket dynamics and distinguishability.

Abstract

Tunnel ionization of room-temperature D$_2$ in an ultrashort (12 femtosecond) near infra-red (800 nm) pump laser pulse excites a vibrational wavepacket in the D2+ ions; a rotational wavepacket is also excited in residual D2 molecules. Both wavepacket types are collapsed a variable time later by an ultrashort probe pulse. We isolate the vibrational wavepacket and quantify its evolution dynamics through theoretical comparison. Requirements for quantum computation (initial coherence and quantum state retrieval) are studied using this well-defined (small number of initial states at room temperature, initial wavepacket spatially localized) single-electron molecular prototype by temporally stretching the pump and probe pulses.