Towards Quantum Information Processing at the Attosecond Timescale

TL;DR

This paper demonstrates quantum information processing at the attosecond timescale using high harmonic emission, revealing electron-photon quantum coherence and entanglement in high-field physics.

Contribution

It introduces a method to generate a photon Hadamard gate and measure electron-trajectory quantum superpositions at attosecond timescales.

Findings

Observation of quantum interference in high harmonic emission

Generation of a photon Hadamard gate at attosecond scale

Measurement of electron-trajectory quantum phases

Abstract

Coherent processing of quantum information and attosecond science had so far little in common. We here show that recent data in high harmonic emission reveal quantum information processing at the attosecond timescale. By observing the interference pattern created by the spatiotemporal overlap of photons emitted by two interfering electron paths we generate a photon Hadamard gate and thus erase the electron-trajectory information. This allows the measurement of the relative phase in electron-trajectory quantum superpositions and establishes the era of electron-photon quantum coherence and entanglement at the attosecond timescale of high-field physics.