Meng Cheng (physicist)

Symmetry-enriched topological order

Cheng worked on symmetry-enriched topological order, which concerns how global symmetries interact with the emergent topological properties of quantum phases. In collaboration with Maissam Barkeshli, Parsa Bonderson, and Zhenghan Wang, he developed a theoretical framework for characterizing symmetry fractionalization, extrinsic defects, and gauging in (2+1)-dimensional topological phases. This work introduced the formalism of G-crossed braided tensor categories to systematically classify symmetry-enriched topological phases and compute properties of symmetry defects.^[6]

He also studied the constraints imposed by translation symmetry on symmetry-enriched topological phases, connecting the Lieb-Schultz-Mattis theorem and its generalizations to the bulk-boundary correspondence for translation symmetry-protected topological phases.^[7]

Topological superconductivity

Cheng's early work addressed topological superconductivity and Majorana-based quantum computation. His doctoral research established theoretical frameworks for understanding Majorana qubits in non-Abelian topological superconductors, including studies of their stability and decoherence properties.^[1] He proved that a large class of two-dimensional spinless fermion models with certain symmetries generically exhibit topological superconducting phases.^[8]

Fracton phases and quantum criticality

Cheng's more recent research includes work on fracton phases—exotic quantum phases characterized by excitations with restricted mobility—and quantum criticality, including the study of extended observables and defects at quantum critical points. He has also developed a topological holographic framework for understanding (1+1)-dimensional quantum phases, including quantum critical points between symmetry-protected topological phases.^[9]

Mixed-state quantum phases

Cheng has contributed to extending the classification of topological quantum phases from pure ground states to mixed states and disordered ensembles, including the identification of intrinsically disordered average-symmetry-protected topological phases and the study of mixed-state quantum anomalies.^[10]