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The Hartree-Fock-Bogolyubov mean fields

Since the Bogolyubov transformation does not preserve the particle number, we introduce two Lagrange multipliers $ \lambda_N$ and $ \lambda_Z$ to conserve the average neutron and proton number. The HFB equations are then obtained by writing the stationary condition $ \delta \left[\mathcal{E}-\langle\lambda_N N +\lambda_Z Z\rangle\right]=0$. The dependence of $ \mathcal{E}$ on the kinetic densities leads the effective mass

$\displaystyle M_q$ $\displaystyle =$ $\displaystyle \displaystyle \frac{\hbar^2}{2m^*_q}\hfill$ (22)
  $\displaystyle =$ $\displaystyle \displaystyle \frac{\hbar^2}{2m}+\frac{t_1}{4}
\left[\left(1+\frac{x_1}{2}\right)\rho
-\left(x_1+\frac{1}{2}\right)\rho_q\right]\hfill$  
    $\displaystyle \hskip 1.4cm +\frac{t_2}{4}\left[\left(1+\frac{x_2}{2}\right)\rho
+\left(x_1+\frac{1}{2}\right)\rho_q\right]$ (23)

and to the abnormal effective mass

$\displaystyle \tilde M_q=\frac{t_1'}{4}(1-x_1')\tilde\rho_q\,.$ (24)

The particle-hole (Hartree-Fock) fields is given by
$\displaystyle U_q$ $\displaystyle =$ $\displaystyle \displaystyle
t_0\left[\left(1+\frac{x_0}{2}\right)\rho
-\left(x_0+\frac{1}{2}\right)\rho_q\right] \hfill$  
  $\displaystyle +$ $\displaystyle \displaystyle
\frac{t_1}{4}\left[\left(1+\frac{x_1}{2}\right)
\le...
..._1+\frac{1}{2}\right)\left(\tau_q-\frac{3}{2}\Delta\rho_q\right)
\right] \hfill$  
  $\displaystyle +$ $\displaystyle \displaystyle
\frac{t_2}{4}\left[\left(1+\frac{x_2}{2}\right)
\le...
..._2+\frac{1}{2}\right)\left(\tau_q+\frac{1}{2}\Delta\rho_q\right)
\right] \hfill$  
  $\displaystyle +$ $\displaystyle \displaystyle
\frac{t_3}{12}\left[\left(1+\frac{x_3}{2}\right)(2+...
...mma\rho^{\gamma-1}\sum_{q'}\rho_{q'}^2
+2\rho^\gamma\rho_q\right)\right] \hfill$  
  $\displaystyle +$ $\displaystyle \displaystyle
\frac{t_3'}{24}(1-x_3')\gamma'\rho^{\gamma'-1}
\sum_{q'}\tilde\rho_{q'}^2 \hfill$  
  $\displaystyle -$ $\displaystyle \displaystyle
\frac{W_0}{2}\left(\nabla J+\nabla J_q\right)$ (25)

In the case of protons, varying the expressions (21) and (22) leads to the following expression for the Coulomb field

$\displaystyle V_c({\mathbf r})=\frac{e^2}{2}\int\, d^3{\mathbf r}'\,\frac{\rho_...
...\vert} -e^2\left(\frac{3}{\pi}\right)^{\frac{1}{3}}\rho_p^{1/3}({\mathbf r})\,.$ (26)

The particle-particle (pairing) field is

$\displaystyle \tilde U_q= \frac{t_0'}{2}(1-x_0')\tilde\rho_q +\frac{t_1'}{4}(1-...
...\Delta\tilde\rho_q\right] +\frac{t_3'}{12}(1-x_3')\rho^{\gamma'}\tilde\rho_q\,.$ (27)

Finally, the spin-orbit fields ( $ \propto\boldsymbol\ell\cdot\mathbf s$) have the following form factors:

$\displaystyle B_q=-\frac{1}{8}\left(t_1x_1+t_2x_2\right)J+\frac{1}{8} (t_1-t_2)J_q+W_0\nabla(\rho+\rho_q)\,,$ (28)

$\displaystyle \tilde B_q=\left[\frac{t_2'}{2}(1+x_2')+W_0'\right]\tilde J_q\,.$ (29)


next up previous
Next: The Hartree-Fock-Bogolyubov equations Up: The Skyrme Hartree-Fock-Bogolyubov equations Previous: The Hartree-Fock-Bogolyubov energy
Jacek Dobaczewski 2005-01-23