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[QUE/CM-04009]

Node id: 2846page

The Lagrangian for a symmetric top, in terms of Euler angles  $\theta,\phi,\psi$ is given by $$ L = {1\over2} I_1  \left(\dot{\theta}^2 + \dot{\phi}^2 \sin^2\theta \right) +{1\over2} I_3 (\dot{\psi} + \dot{\phi} \cos\theta)^2 - mgL\cos\theta $$

  1. Compute the canonical momenta conjugate to $\theta,\phi,\psi.$
  2. Show that the Hamiltonian in terms of momenta $p_\theta, p_\phi$ and $p_\psi$ the Euler angles is given by $$H=\frac{p_\theta^2}{2I_1} + \frac{(p_\psi -p_\phi \cos\theta)^2}{2 I_1 \sin^2\theta} + \frac{p_\psi^2}{2I_3} + mgL\cos\theta$$
kapoor's picture 22-04-09 15:04:12 n

[QUE/CM-04008]

Node id: 2845page

Compute the following Poisson brackets.

  1. $[\vec{a}\cdot\vec{L},\vec{b}\cdot\vec{L}]_\text{PB}$
  2. $[L_1, x_3]_\text{PB}$   
  3. $[\vec{p}, r^n]_\text{PB}$

 

kapoor's picture 22-04-09 14:04:27 n

[QUE/CM-04020]

Node id: 2851page

Compute the Poisson brackets of \(x\)- component of angular momentum  \(L_x\) with the following quantities.

  1. \(\vec{r}\cdot \vec{p}\)
  2. \( p_y\)
  3. \(z\)
  4. \(\vec{p}^{\, 2}\)
kapoor's picture 22-04-09 14:04:52 n

[QUE/CM-04017]

Node id: 2852page

The Lagrangian for a system with one degree of freedom is given by \[ L=\frac{1}{2} m  \dot{x}^2 - \omega^2 x^2 -\alpha x^4 + \beta x \dot{x}^2\]

  1. Obtain the momentum conjugate to \(x\) and the Hamiltonian
  2. Write the Hamiltonian equations of motion.
kapoor's picture 22-04-09 14:04:16 n

[QUE/CM-05017]

Node id: 2861page

A body of mass $\mu$ is projected  from a  hypothetical planet, mass $16M$ and radius $2R$, towards another planet of mass $M$ and radius $R$. Plot the gravitational potential seen by the body  as function of distance from the center of the first planet. The distance between the  centers of the planet is given to be $10R.$

  1. Find the equilibrium point, if any, on the line joining the two planets.
  2. Discuss what happens when the particle is displaced a little towards one of the planets. Is the equilibrium stable or unstable?
  3. Find the minimum velocity with which the particle be projected from the surface of the first planet so that it may reach the second planet.
kapoor's picture 22-04-09 14:04:15 n

[QUE/CM-05016]

Node id: 2862page

When a small correction  $\delta U(r)$  is added to the potential energy  $U=-{\alpha\over r}$, the paths of finite motion are no longer closed, and  at each revolution the perihelion is  dipslaced through a small angle  $\delta \phi$. Show that $\delta \phi$  is approximately given by  $$ \delta \phi = {\partial \over \partial M} \int_{r_1}^{r_2}  { 2M\delta U dr\over \sqrt{ 2m(E +\alpha/r)-M^2/r^2  }} =  {\partial \over \partial M}\left(\frac{2m}{M} \int_{0}^{\pi}   r^2\delta U d\phi \right)  $$  where $r_1, r_2$ are the minimum and the maximum values of $r$. Find $\delta \phi$ when $\delta U = {\beta \over r^2  }$.

kapoor's picture 22-04-09 14:04:46 n

[QUE/CM-05015]

Node id: 2863page

For a particle  moving in a spherically symmetric potential the three  components of angular momentum are conserved. For a potential depending on $r$ as well as $\vec{n}\cdot\vec{r}$ ( $\vec{n} = $  a fixed vector) prove that only the component of angular momentum along $\vec{n}$ is conserved.

kapoor's picture 22-04-09 14:04:42 n

[QUE/CM-05014]

Node id: 2864page

Under what conditions does a particle moving in a potential $ -{\alpha \over r^2}$ fall to the center? Find the time taken in falling the center from point $r=r_0$.

kapoor's picture 22-04-09 14:04:52 n

[QUE/CM-05012]

Node id: 2866page

Find the time dependence of coordinates $(x,y)$ of a particle with energy  $E=0$ moving in a parabola in a potential $$V(r)= - {k\over r}.$$

kapoor's picture 22-04-09 14:04:41 n

[QUE/CM-05011]

Node id: 2867page

  Solve the equations of motion, in polar coordinates, for an isotropic oscillator in two dimension   with potential given by $V(r) ={1\over 2} m \omega^2 r^2$

kapoor's picture 22-04-09 14:04:45 n

[QUE/CM-05010]

Node id: 2868page

A particle moves in a central potential $$ V(r) = -{\alpha \over r^2} $$       and has energy $E$, angular momentum $L$. Show that the orbit of the particle is given by $$ {1\over r} = \sqrt{2mE\over L^2 -2m\alpha } \cos ( \lambda (\phi + \delta))$$  where $\lambda ^2 =1- {2m\alpha \over L^2}$

kapoor's picture 22-04-09 14:04:53 n

[QUE/CM-05009]

Node id: 2869page

 For a particle moving in Coulomb potential $V(r) = k/r$ show that  the Runge Lenz vector  $$ \vec{N} = \vec{v}\times\vec{L} - k \vec{r}/r  $$   is a constant of motion where $\vec{v}$ is the velocity, and $\vec{L}$  is the angular momentum of the particle

kapoor's picture 22-04-09 14:04:00 n

[QUE/CM-05008]

Node id: 2870page

Consider the motion in a spherically symmetric potential $$ V(r) = - V_0  \left( {3 R\over r } + {R^3\over r^3} \right)$$ If orbital angular momentum of the particle is given by $l^2 = 10 m V_0 R^2$, plot the potential as a function of $r$ and answer the following questions.

  1. What is the minimum energy so that particle coming from infinity may fall to the center?
  2. What should be the energy of the particle so that it may move in a circular orbit? Find the radius of the orbit.

 

kapoor's picture 22-04-09 14:04:41 n

[NOTES/QCQI-01004] Positive Operators

Node id: 5021page
AK-47's picture 22-04-08 13:04:09 y

[ NOTES/QCQI-01003] Trace and Partial Trace

Node id: 5020page
AK-47's picture 22-04-08 13:04:46 y

[NOTES/QCQI-04001] Single Qubit Quantum Gates

Node id: 5030page
AK-47's picture 22-04-08 13:04:54 y

[NOTES/QCQI-04002] Two Qubit Gates

Node id: 5031page
AK-47's picture 22-04-08 13:04:01 y

[QUE/CM-05006]

Node id: 2871page

Sketch the equivalent one dimensional potential for the central force corresponding to \(F=-\frac{3a}{r^4}\) Sketch the values of \(E^\prime\) such that a circular orbit is possible, state the conditions for the bound orbit  if any.

kapoor's picture 22-04-08 08:04:25 n

[QUE/CM-05005

Node id: 2872page

Sketch the equivalent one dimensional potential for the centralforce corresponding to \(F=-\frac{3a}{r^4}\). A particle  with energy \(E\) and angular momentum \(\ell\)  approaches the centre of force. Find condition(s) on energy and the angular momentum such that the values of \(E^\prime\) such that the particle may fall to the centre.

kapoor's picture 22-04-08 08:04:36 n

[QUE/CM-05004]

Node id: 2873page

Sketch the equivalent one dimensional potential for the central force corresponding to \(F=-\frac{3a}{r^4}\) Draw the value of \(E^\prime\) such that a bound orbit is possible, state the conditions for the bound orbit

kapoor's picture 22-04-08 08:04:53 n

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