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  1. QuantumRose

    Find the range of acceleration so that the drums won't fall

    Problem: Attempt: I tried to solve the range by listing out the newton's 2nd laws of each drum and from the equations of the drum 2, I get Since drum 2 must stay on the bottom drums, so it will not fly up, thus I got the upper bound of the acceleration, but I don't know if it is...
  2. QuantumRose

    About the derivation of Lorentz gauge condition

    The question: Show that the Lorentz condition ∂µAµ =0 is expressed as d∗ A =0. Where A is the four-potential and * is the Hodge star, d is the exterior differentiation. In four-dimensional space, we know that the Hodge star of one-forms are the followings. 3. My attempt Since the four...
  3. QuantumRose

    Commutator relations of field operators

    Here is the question: By using the equality (for boson) ---------------------------------------- (1) Prove that Background: Currently I'm learning things about second quantization in the book "Advanced Quantum Mechanics"(Franz Schwabl). Given the creation and annihilation operators(), define...