A multidimensional approach to quantum state tomography of photoelectron wavepackets

Area of Science:

• Quantum optics
• Atomic physics
• Spectroscopy

Background:

• Reconstructing photoelectron density matrices is crucial for understanding complex quantum systems.
• Current quantum state tomography methods are often complex, requiring extensive measurements or fitting.
• Developing efficient, single-scan protocols is essential for studying more systems.

Purpose of the Study:

• To develop a novel, efficient single-scan protocol for reconstructing the continuous variable density matrix of photoelectrons.
• To overcome limitations of existing quantum state tomography methods.

Main Methods:

• Proposing a new protocol based on measuring photoelectron coherences.
• Utilizing a time-scanned broadband infrared (IR) probe and a fixed narrowband IR reference pulse after extreme ultraviolet (XUV) photoionization.
• Applying the protocol to Fano resonances in Helium and spin-orbit split states in Argon.

Main Results:

• Demonstrated excellent fidelity in density matrix reconstruction.
• Achieved near-perfect estimation of quantum state purity.
• Successfully applied to complex atomic systems like Helium and Argon.

Conclusions:

• The proposed protocol offers a significant advancement in efficiency for photoelectron quantum state reconstruction.
• This method facilitates the study of a wider range of complex quantum systems.
• Enables high-fidelity, model-free density matrix reconstruction in a single scan.