Computing specific heat

Question

Dear Miles,

is there an easy way in ITensor to compute the specific heat of a chain? Namely is the operator H^2 already implemented somewhere or could it be generated easily with AutoMPO?

Thanks a lot!

All the best,
Jacopo

Answer 1

Hi Jacopo,

To create $H^2$, you could always create $H$ with AutoMPO and then use the function nmultMPO to multiply the MPO $H$ with itself.

Otherwise, to use AutoMPO, you would have to write out by hand all of the terms resulting from $H^2$, and input those terms into AutoMPO. This shouldn't be too bad for a Hamiltonian with local interactions.

Cheers,
Matt