# Anderson orthogonality catastrophe in $2+1$-D topological systems

## TL;DR

This paper investigates the Anderson orthogonality catastrophe in 2+1-dimensional topological systems, revealing universal topological response terms and unique decay behaviors in ground-state overlaps that can identify topological phases and edge modes.

## Contribution

It uncovers universal topological response terms in ground-state overlaps for 2+1D topological systems and identifies a faster decay in Laughlin states beyond AOC.

## Key findings

- Universal topological response term in ground-state overlap scaling
- Faster-than-exponential decay in Laughlin wave functions
- Finite-size scaling as a tool to detect topological features

## Abstract

In the thermodynamic limit, a many-body ground state has zero overlap with another state which is a slightly perturbed state of the original one, known as the Anderson orthogonality catastrophe (AOC). The amplitude of the overlap for two generic ground states typically exhibits exponential or power-law decay as the system size increases to infinity. In this paper, we show that for generic $(2+1)$-D topological systems at fixed points, there exists a universal topological response term in the scaling of the ground-state overlap. For Laughlin wave functions, in particular, we also find a leading term decaying faster than exponential, which is beyond AOC. Such finite-size scaling behaviors could be utilized to theoretically detect the gapless edge modes, distinguish the topology of quantum states or serve as a signature for topological phase transitions.