I don't know if this question should be in the quantum physics section, so i'm just posting it here. So I have doubts regarding matter wave and electromagnetic waves associated with electron or just any particle. 1. So I understand when an electron is accelerated, it produces electromagnetic waves because it is a charged particle. It also has matter waves associated with it by virtue of its mass. My question is, are these matter waves 'emitted' just like electromagnetic waves ? Can they be visualized as being emitted from an electron just like electromagnetic waves ? And also, since a wave is basically a disturbance created by a certain entity, what is the entity causing the 'disturbance' for matter waves. 2. Is the wavelength associated with a matter wave and electromagnetic wave the same ? My textbook has an expression for the de Broglie wavelength associated with an electron given by, wavelength = 1.227/sqrt(V), where V is the potential difference by which it is accelerated. They have used de Broglie's relation to prove this relation, however the derivation starts with the consideration that an electron is being accelerated through a potential of V. So for an electron that is not being accelerated, what is the associated de Broglie wavelength ? And why does the electron have to be accelerated to calculate its de Broglie wavelength. 3. Finally, does an electron or any particle have to be accelerated to 'emit' matter waves? Or are matter waves even emitted for stationary objects ?