<p>➀ Researchers at TU Wien have discovered a new physical phenomenon that exists between metals and insulators, which they describe as a 'quantum umbilical cord.';</p><p>➁ This phenomenon occurs when the interaction strength between electrons is sufficiently large, leading to additional energy states between metallic and insulating materials;</p><p>➂ The discovery opens up new perspectives in material science and technology, suggesting that there are more states between conductors and insulators than previously thought.</p>