Scaling behavior of electron decoherence in a graphene Mach-Zehnder interferometer

Area of Science:

• Condensed Matter Physics
• Quantum Information Science
• Materials Science

Background:

• Decoherence in 2D electron systems has limited quantum manipulations for two decades.
• GaAs heterostructures have been used for electronic interferometers to mitigate decoherence.
• Intrinsic decoherence sources remain a fundamental challenge in advanced quantum control.

Purpose of the Study:

• To investigate graphene as a platform for exploring frozen decoherence regimes.
• To study electron interferometry in a graphene quantum Hall PN junction.
• To unveil novel decoherence scaling behaviors in graphene-based interferometers.

Main Methods:

• Fabrication and characterization of a graphene quantum Hall PN junction Mach-Zehnder interferometer.
• Probing electron channel decoherence within the interferometer.
• Analyzing the scaling of interference visibility decay with temperature and interferometer length.

Main Results:

• Graphene facilitates a regime of significantly reduced decoherence.
• Observed a unique scaling behavior of interference visibility decay.
• Identified a crossover from exponential to algebraic decay with decreasing temperature.

Conclusions:

• Graphene offers a unique system to study decoherence-free electron interferometry.
• The observed crossover highlights a novel decoherence regime previously inaccessible in GaAs.
• Findings pave the way for advanced quantum manipulations in graphene-based devices.