Detecting Bulk Topology of Quadrupolar Phase from Quench Dynamics

Area of Science:

• Condensed Matter Physics
• Quantum Materials
• Topological Phases of Matter

Background:

• Direct measurement of bulk topological observables remains challenging.
• Detecting bulk topology via quench dynamics is an emerging research area.
• Quantum quadrupole insulators possess unique topological properties.

Purpose of the Study:

• To propose a novel method for detecting topological characteristics of quantum quadrupole insulators.
• To introduce a new observable, the chiral quadrupole moment, for identifying topological phases.
• To demonstrate the efficacy of this method for both noninteracting and interacting systems.

Main Methods:

• Utilizing quench dynamics to probe topological properties.
• Defining and calculating a quadrupole moment weighted by chiral operator eigenvalues.
• Employing efficient numerical methods to track unitary time evolution.
• Investigating the system's response to disorders.

Main Results:

• The proposed chiral quadrupole moment is zero in trivial phases and finite in topological quadrupolar phases.
• This observable reliably distinguishes between topological and trivial phases.
• The method is effective for both noninteracting and interacting systems.
• The topological indicator demonstrates robustness against disorder.

Conclusions:

• Quench dynamics provide a viable route for detecting bulk topology in quantum materials.
• The chiral quadrupole moment serves as a robust indicator of topological phases in quantum quadrupole insulators.
• This approach offers a new tool for characterizing topological matter.