Experimentalists used an entangled state of two photons to show that time is going in different way for internal and external observers. Here, within the Scale-Symmetric Theory (SST), we show that such scenario concerns the elliptical states of electron in atoms. There are two different entangled circular states of an elliptical state. The jumps of entanglon (entanglons are responsible for quantum entanglement) between them cause that global energy is static whereas an internal observer associated with one of two entangled circular states (the clock) sees evolution of the other circular state. It is the duality of time from quantum entanglement. Similar mechanism concerns two mass states of proton and of neutron but there is exchanged not an entanglon but electric charge between the very dense gluon fields in nucleons. The exchanges lead to the mean fractional charges of such gluon fields.