An Aharonov-Bohm interferometer for determining Bloch band topology

Area of Science:

• Condensed Matter Physics
• Quantum Mechanics
• Atomic Physics

Background:

• The geometric structure of single-particle energy bands dictates many-body phenomena in solids.
• Berry curvature distribution in the Brillouin zone is key to characterizing band structures.
• Topological band structures are essential for novel quantum phenomena.

Purpose of the Study:

• To develop and demonstrate an atomic interferometer for measuring Berry flux in momentum space.
• To characterize topological band structures with high momentum resolution.
• To provide a general framework for analyzing topological properties of electronic bands.

Main Methods:

• Realization of an atomic interferometer using a graphene-type hexagonal optical lattice.
• Loading the optical lattice with bosonic atoms.
• Detection of Berry flux localized at Dirac points in momentum space.

Main Results:

• Successful demonstration of an atomic interferometer analogous to the Aharonov-Bohm effect.
• Detection of singular π Berry flux at each Dirac point in the hexagonal lattice.
• Establishment of the high momentum resolution capabilities of the interferometric technique.

Conclusions:

• The atomic interferometer provides a novel method for probing Berry curvature and topological band structures.
• This technique offers high precision in measuring momentum-space properties.
• The developed framework is applicable to a broader range of topological band structure characterization.