Half-integer thermal conductance in integer quantum Hall states

Area of Science:

• Condensed Matter Physics
• Quantum Materials
• Topological Quantum Computing

Background:

• Half-integer thermal conductance is widely considered a hallmark of non-Abelian states.
• These states are associated with Majorana edge modes, crucial for topological quantum computing.
• Existing theories link fractional thermal conductance values to non-trivial topological properties.

Purpose of the Study:

• To investigate alternative origins of half-integer thermal conductance.
• To challenge the prevailing notion that it exclusively signifies non-Abelian states.
• To explore the role of equilibration dynamics in quantized transport phenomena.

Main Methods:

• Theoretical modeling and experimental realization using bilayer graphene.
• Confined geometry featuring distinct integer quantum Hall edges (particle- and hole-like).
• Ensuring full charge and thermal equilibration across device segments.

Main Results:

• Demonstrated realization of a half-integer two-terminal thermal conductance plateau.
• Achieved this plateau using conventional integer quantum Hall states, not non-Abelian states.
• Showcased robust non-integer thermal conductance values arising from equilibration dynamics.

Conclusions:

• Robust non-integer thermal conductance can manifest from mundane equilibration dynamics.
• This challenges the exclusive link between half-integer thermal conductance and non-Abelian topology.
• The approach is generalizable to other quantum Hall platforms for fractional transport studies.