English

Computational Difficulty of Computing the Density of States

Quantum Physics 2011-07-22 v2 Computational Complexity

Abstract

We study the computational difficulty of computing the ground state degeneracy and the density of states for local Hamiltonians. We show that the difficulty of both problems is exactly captured by a class which we call #BQP, which is the counting version of the quantum complexity class QMA. We show that #BQP is not harder than its classical counting counterpart #P, which in turn implies that computing the ground state degeneracy or the density of states for classical Hamiltonians is just as hard as it is for quantum Hamiltonians.

Keywords

Cite

@article{arxiv.1010.3060,
  title  = {Computational Difficulty of Computing the Density of States},
  author = {Brielin Brown and Steven T. Flammia and Norbert Schuch},
  journal= {arXiv preprint arXiv:1010.3060},
  year   = {2011}
}

Comments

v2: Accepted version. 9 pages, 1 figure

R2 v1 2026-06-21T16:28:48.418Z