Interference between two indistinguishable electrons from independent sources

Area of Science:

• Quantum physics
• Condensed matter physics
• Quantum optics

Background:

• Quantum interference is fundamental, observed in single particles and two-particle systems via exchange statistics.
• Experimental verification of two-particle interference, particularly with electrons, is challenging due to source and synchronization issues.
• Previous electron experiments focused on auto-correlation (shot noise), unlike optical experiments that observed photon bunching.

Purpose of the Study:

• To experimentally demonstrate quantum interference and orbital entanglement between two independent electron beams.
• To implement an electronic analogue of the Hanbury Brown and Twiss experiment using a Mach-Zehnder interferometer.
• To investigate the role of Aharonov-Bohm flux on electron current fluctuations and cross-correlations.

Main Methods:

• Utilized edge channels in the quantum Hall effect regime to create an electronic Mach-Zehnder interferometer.
• Partitioned two independent, mutually incoherent electron beams into four trajectories enclosing an Aharonov-Bohm flux.
• Measured auto-correlation of individual currents and cross-correlation between current fluctuations at opposite points.

Main Results:

• Individual electron currents and their shot noise (auto-correlation) showed no dependence on the Aharonov-Bohm flux.
• Cross-correlation measurements between current fluctuations exhibited distinct Aharonov-Bohm oscillations.
• These oscillations provide evidence for orbital entanglement between the two electron beams.

Conclusions:

• The experiment successfully demonstrated quantum interference and orbital entanglement between independent electron beams.
• Cross-correlation measurements are a sensitive probe for detecting orbital entanglement in electronic systems.
• The findings pave the way for new quantum information processing schemes using electron entanglement.