If we have Lagrangian $\mathcal{L} = \frac{i}{2} \left[ \bar{\psi} \gamma^\mu \partial_\mu \psi - (\partial_\mu \bar{\psi}) \gamma^\mu \psi \right] - m \bar{\psi} \psi$ find the equation of motion of this system where the field are $\psi$ and $\bar{\psi}$ $\gamma^\mu$: Constant matrix.
Added by -Ngeles S.
Close
Step 1
So, we need to find the partial derivatives with respect to x and dx/dt. ∂L/∂(dx/dt) = iq ∂L/∂x = iq - 16x^3 Now, let's substitute these derivatives into the Lagrangian equation of motion: d/dt (∂L/∂(dx/dt)) - ∂L/∂x = 0 d/dt (iq) - (iq - 16x^3) = 0 i(dq/dt) - Show more…
Show all steps
Your feedback will help us improve your experience
Geeta Yadav and 57 other Physics 103 educators are ready to help you.
Ask a new question
Labs
Want to see this concept in action?
Explore this concept interactively to see how it behaves as you change inputs.
Key Concepts
Recommended Videos
The Lagrangian for a mechanical system is L = aq^2 + bq^4, where q is a generalized coordinate and a, b are constants. The equation of motion for this system is
Adi S.
For matrix A below, make a change of variables that decouples the equation x' = Ax. Write the equation x(t) = Py(t) that leads to the uncoupled system y' = Dy, specifying P and D. A = [[10, -3], [5, 2]] Choose the correct values of P and D below that result in the decoupled system y' = Dy when x(t) = Py(t). A. P = [[-5, 1], [-3, 1]], D = [[7, 0], [0, 5]] B. P = [[3, 1], [5, 1]], D = [[7, 0], [0, 5]] C. P = [[3, 1], [5, 1]], D = [[5, 0], [0, 7]] D. P = [[1, -3], [1, 5]], D = [[5, 0], [0, 7]] Write the equation x(t) = Py(t) using the matrix P found above. x(t) = []y(t)
Sri K.
Find all constant solutions x(t) = [x1(t); x2(t); x3(t)] (i.e. x1, x2, x3 are actually constant functions) to the following system of differential equations x' = [2 0 -1; 1 1 2; 0 0 0]x. Note that the columns of this matrix is the same as the three vectors in part (b). Hint: what is x'(t) when x(t) is constant?
Recommended Textbooks
University Physics with Modern Physics
Physics: Principles with Applications
Fundamentals of Physics
Watch the video solution with this free unlock.
EMAIL
PASSWORD