Parameter: nmonte

Definition

How often to measure the physical observables.

Type

Integer

Default value

10

Component

ALL

Behavior

Every nmonte Monte Carlo sampling steps, the quantum impurity solvers try to measure the physical observables. The affected physical observables are as follows:

• Impurity occupancy, $\langle n_{\alpha} \rangle$, $\langle n_{\alpha}n_{\beta} \rangle$,
• Impurity Matsubara Green's function, $G(i\omega_n)$,
• Spin-spin correlation function, $\langle S_z(0) S_z(\tau) \rangle$, $\chi_{\text{sp}}(i\nu_n)$,
• Orbital-orbital correlation function, $\langle n_{\alpha}(0) n_{\beta}(\tau)\rangle$, $\chi_{\text{ch}}(i\nu_n)$,
• Momentum of kinetic energy, $\langle k^2 \rangle - \langle k \rangle^2$,
• Fidelity susceptibility, $\langle k_L k_R \rangle - \langle k_L \rangle \langle k_R \rangle$,
• Two-particle Green's function, $\chi(i\omega_n,i\omega_n,i\nu_n)$,
• Two-particle vertex function, $\mathcal{F}(i\omega_n,i\omega_n,i\nu_n)$,
• Pairing susceptibility, $\Gamma(i\omega_n,i\omega_n,i\nu_n)$,.

The measuring period for the other physical observables are controlled by the ncarlo parameter. See also ncarlo parameter for more details.

Comment

You can increase nmonte to relieve the auto-correlation of physical observables between two successive measurements. However, large nmonte will waste the CPU times. It is recommended that a good nmonte should satisfy the following relation:

\[\text{nmonte} * \text{P}_{\text{insert}} >= 1.0\]

Here, $\text{P}_{\text{insert}}$ means the accepted ratio for the insert update actions.