This study investigates the potential energy landscape (PEL) of a Cu64.5Zr35.5 metallic glass, revealing that the energy barriers between structural states are remarkably low, on the order of 1 meV. This suggests that quantum fluctuations can easily overcome these barriers, challenging the assumption that metallic glasses are completely frozen at the atomic level. The research uses molecular dynamics simulations to track mechanical energy loss and atomic-level responses to mechanical perturbations. It finds that at low temperatures, mechanical relaxation is mostly reversible, with lossy atoms remaining lossy. However, at higher temperatures, mechanical relaxation becomes irreversible and transient. The activation energy for local structural changes is found to be around 1 meV, much lower than typical α and β relaxations in metallic glasses. This indicates that the PEL has small ripples at the bottom of basins, which may explain the nearly constant loss observed at low temperatures. The study also shows that quantum fluctuations can easily connect multiple subbasins in the PEL, allowing for rapid transitions between states. The results challenge many assumptions about the thermodynamic states of metallic glasses and suggest that their local structure is not static but fluctuates, even at room temperature. The findings are supported by both simulations and experimental observations, highlighting the complex nature of the PEL in metallic glasses and its role in determining their mechanical behavior.This study investigates the potential energy landscape (PEL) of a Cu64.5Zr35.5 metallic glass, revealing that the energy barriers between structural states are remarkably low, on the order of 1 meV. This suggests that quantum fluctuations can easily overcome these barriers, challenging the assumption that metallic glasses are completely frozen at the atomic level. The research uses molecular dynamics simulations to track mechanical energy loss and atomic-level responses to mechanical perturbations. It finds that at low temperatures, mechanical relaxation is mostly reversible, with lossy atoms remaining lossy. However, at higher temperatures, mechanical relaxation becomes irreversible and transient. The activation energy for local structural changes is found to be around 1 meV, much lower than typical α and β relaxations in metallic glasses. This indicates that the PEL has small ripples at the bottom of basins, which may explain the nearly constant loss observed at low temperatures. The study also shows that quantum fluctuations can easily connect multiple subbasins in the PEL, allowing for rapid transitions between states. The results challenge many assumptions about the thermodynamic states of metallic glasses and suggest that their local structure is not static but fluctuates, even at room temperature. The findings are supported by both simulations and experimental observations, highlighting the complex nature of the PEL in metallic glasses and its role in determining their mechanical behavior.