0 votes
asked by (430 points)

Hi ITensor developer,
Thanks for your reply. I want to calculate The first, second, third,..... (to fifteen exited state) in 1D Heisenberg chain.(my ITensor is version 2 ). Please help me (give some sample) , Thank you very much !

1 Answer

0 votes
answered by (70.1k points)

Hi, to do this you can use the excited state DMRG feature of ITensor. We have put “code formulas” (example codes) on the website at the following links, for each version of ITensor:

Version 2:

Version 3:

Please take care when using this method to compute highly excited states (or really any excited states). It’s important to converge the ground state very well. Also use many sweeps when converging the excited states. For the size of the “Weight” parameter you have to experiment to see what works best for the system you are studying.

Best regards,

Welcome to ITensor Support Q&A, where you can ask questions and receive answers from other members of the community.

Formatting Tips:
  • To format code, indent by four spaces
  • To format inline LaTeX, surround it by @@ on both sides
  • To format LaTeX on its own line, surround it by $$ above and below
  • For LaTeX, it may be necessary to backslash-escape underscore characters to obtain proper formatting. So for example writing \sum\_i to represent a sum over i.
If you cannot register due to firewall issues (e.g. you cannot see the capcha box) please email Miles Stoudenmire to ask for an account.

To report ITensor bugs, please use the issue tracker.