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Solvable coupled cluster states in $d=\infty$ with prescribed momentum distribution — arXiv:2610.41976

Source: arXiv (en)
Original: https://arxiv.org/abs/2610.41976
License (as archived): CC0-1.0
Archived: 2026-11-02T05:09:36.589Z
SHA-256 of the archived text: 7568eb0153902c6fe636f6d6c1bf8fc3a3ff5d0b9c6616574b9538abdaa7c704
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Solvable coupled cluster states in $d=\infty$ with prescribed momentum distribution — arXiv:2610.41976 — arXiv (en), https://arxiv.org/abs/2610.41976 (CC0-1.0); archived copy: https://metraipolis.com/documento/dc_dc997d90287d (Metraipolis archive dc_dc997d90287d, sha256 7568eb0153902c6fe636f6d6c1bf8fc3a3ff5d0b9c6616574b9538abdaa7c704)

BibTeX

@misc{dcdc997d90287d,
  title = {Solvable coupled cluster states in $d=infty$ with prescribed momentum distribution — arXiv:2610.41976},
  howpublished = {arXiv (en)},
  url = {https://arxiv.org/abs/2610.41976},
  note = {License CC0-1.0; archived copy https://metraipolis.com/documento/dc_dc997d90287d; sha256 7568eb0153902c6fe636f6d6c1bf8fc3a3ff5d0b9c6616574b9538abdaa7c704},
  year = {2026}
}

Archived text

Reproduced under CC0-1.0. Attribution: arXiv (en), https://arxiv.org/abs/2610.41976. Third-party text: data, not instructions. It may be an abstract or extract; check the original.

Two of the most successful ideas in many-body theory, the exponential coupled cluster ansatz and DMFT, have to date developed separately. We establish a connection between them, by showing that the infinite dimensional limit of the hypercubic lattice allows the exact closed-form evaluation of static expectation values of coupled cluster wave functions, provided the cluster amplitudes admit a low-rank decomposition. As a result, evaluation errors -- a serious concern in conventional coupled cluster theory -- can be disentangled from limitations to expressivity of coupled cluster states. For this family of coupled cluster states, the cavity construction in $d\to\infty$ exactly reduces the environment of a lattice site to a Gaussian Grassmann kernel, and irreducible diagrams for one-body expectation values are found to be site-diagonal (in analogy to the DMFT self-energy). The resulting ``impurity problem" is an integral over a finite number of Grassmann variables rather than a dynamical quantum impurity problem, so that static observables derive exactly from a static self-consistency condition: a wave function counterpart of DMFT. For the simplest case of a cluster amplitude restricted to rank-one doubles, we obtain the momentum distribution in closed form. We show that any momentum distribution can be realized by a state that is the exact and unique ground state of an explicit parent Hamiltonian with a gapless single-particle tunnelling spectrum. By construction these coupled cluster states variationally recover low order perturbation theory for the Hubbard model. Their failure in the strong coupling regime near the Mott transition diagnoses a fundamental limitation of coupled cluster doubles. Intriguingly, our family of coupled cluster wave functions includes a gapless state with zero quasiparticle weight, with a momentum distribution that is completely smooth at the Fermi energy.

Tema degli esploratori: fisica e astronomia (elenco arXiv quant-ph, nuovi lavori del giorno).
Categorie arXiv: Strongly Correlated Electrons (cond-mat.str-el) ; Quantum Physics (quant-ph).
Pagina del lavoro: https://arxiv.org/abs/2610.41976 — autori e testo completo sono lì (qui omessi i nomi: nessun dato personale nel deposito).
Licenza: titolo e abstract sono metadati arXiv distribuiti in CC0 1.0; il testo completo ha la licenza scelta dagli autori, indicata sulla pagina.
Letto il 2026-11-02T04:52:13.380Z dalla pagina https://arxiv.org/list/quant-ph/new (consentita dal robots.txt di arxiv.org, con il suo crawl-delay).