Recent content by chmodfree

  1. chmodfree

    To prove that a coherent state is an eigenstate of the annihilation operator

    The definition of coherent state $$|\phi\rangle =exp(\sum_{i}\phi_i \hat{a}^\dagger_i)|0\rangle $$ How can I show that the state is eigenstate of annihilation operator a? i.e. $$\hat{a}_i|\phi\rangle=\phi_i|\phi\rangle$$
  2. chmodfree

    Undergrad Generalized Momentum is a linear functional of Velocity?

    I mean it maps \dot{Q} from tangent bundle to the real number field as a functional... No problem now, thank you.
  3. chmodfree

    Undergrad Generalized Momentum is a linear functional of Velocity?

    Oh I see, that means the contraction P_a\dot{Q}^a is a real.
  4. chmodfree

    High School A question about optics: Why does a pinhole aperture work like my eyeglasses?

    The smaller the aperture, the greater the depth of field. You can find when taking photo.
  5. chmodfree

    Undergrad Can an electron be found outside the atom it belongs to?

    According to tunneling effect, there is a certain probability of stationary state electron appear in whole space, even they are in bound state. When the eletron reach the space where Coulomb potential is greater than its stationary state energy, the probability decline exponentially.
  6. chmodfree

    Undergrad Generalized Momentum is a linear functional of Velocity?

    Generalized momentum is covariant while velocity is contravariant in coordinate transformation on configuration space, thus they are defined in the tangent bundle and cotangent bundle respectively. Question: Is that means the momentum is a linear functional of velocity? If so, the way to...
  7. chmodfree

    Undergrad Question about Operators in Quantum Mechanics

    You can regard the momentum operator as generator of spatial translation group.