The paper explores the connection between optical response and ground-state quantum geometry and topology in antiferromagnetic topological insulator MnBi₂Te₄ thin films. Using first-principles calculations, the authors demonstrate that the generalized optical weight, defined as the first negative moment of the absorptive part of the optical conductivity, can probe these quantum geometric properties. They show that three septuple layers (SLs) of MnBi₂Te₄ exhibit enhanced magnetic circular dichroism (MCD) for a narrow photon energy window in the infrared region. The quantum weight, a key quantity related to the quantum metric, is calculated and found to exceed the lower bound provided by the Chern number. The study also reveals that the Chern insulator state in MnBi₂Te₄ shows an almost perfect MCD, with the imaginary part of the optical weight converging to the quantized Chern number. The results highlight the potential of optical methods for probing ground-state quantum geometry and topology in real materials, which could have practical applications in optoelectronics.The paper explores the connection between optical response and ground-state quantum geometry and topology in antiferromagnetic topological insulator MnBi₂Te₄ thin films. Using first-principles calculations, the authors demonstrate that the generalized optical weight, defined as the first negative moment of the absorptive part of the optical conductivity, can probe these quantum geometric properties. They show that three septuple layers (SLs) of MnBi₂Te₄ exhibit enhanced magnetic circular dichroism (MCD) for a narrow photon energy window in the infrared region. The quantum weight, a key quantity related to the quantum metric, is calculated and found to exceed the lower bound provided by the Chern number. The study also reveals that the Chern insulator state in MnBi₂Te₄ shows an almost perfect MCD, with the imaginary part of the optical weight converging to the quantized Chern number. The results highlight the potential of optical methods for probing ground-state quantum geometry and topology in real materials, which could have practical applications in optoelectronics.