Re: units
28 views
Skip to first unread message
Simon Cross
Dec 4, 2022, 11:35:44 AM12/4/22
to qu...@googlegroups.com
Hi Alexander,
In regards to the units used:
In QuTiP Hamiltonians are viewed as already having been divided by
h-bar, or that h-bar is 1 in the units being used. For example, the
RHS of the Schrödinger equation is just -i * H and the Liouvillian is
-i * (spre(H) - spost(H)) + dissipation terms. So when creating
Hamiltonian in QuTiP either divide by h-bar or just use units in which
h-bar is 1.
In regards to the negative expectation values for the number operator:
If the negative numbers are small, that is likely due to small
numerical errors. You should be able to make them smaller by
decreasing the tolerances at the top of the script (at the cost of the
solver taking longer to execute).
Regards,
Simon
In regards to the units used:
In QuTiP Hamiltonians are viewed as already having been divided by
h-bar, or that h-bar is 1 in the units being used. For example, the
RHS of the Schrödinger equation is just -i * H and the Liouvillian is
-i * (spre(H) - spost(H)) + dissipation terms. So when creating
Hamiltonian in QuTiP either divide by h-bar or just use units in which
h-bar is 1.
In regards to the negative expectation values for the number operator:
If the negative numbers are small, that is likely due to small
numerical errors. You should be able to make them smaller by
decreasing the tolerances at the top of the script (at the cost of the
solver taking longer to execute).
Regards,
Simon
Reply all
Reply to author
Forward
0 new messages