{"external_id":{"arxiv":["1909.05981"]},"date_created":"2019-09-16T07:41:31Z","status":"public","abstract":[{"text":"The canonical problem for the class Quantum Merlin-Arthur (QMA) is that of\r\nestimating ground state energies of local Hamiltonians. Perhaps surprisingly,\r\n[Ambainis, CCC 2014] showed that the related, but arguably more natural,\r\nproblem of simulating local measurements on ground states of local Hamiltonians\r\n(APX-SIM) is likely harder than QMA. Indeed, [Ambainis, CCC 2014] showed that\r\nAPX-SIM is P^QMA[log]-complete, for P^QMA[log] the class of languages decidable\r\nby a P machine making a logarithmic number of adaptive queries to a QMA oracle.\r\nIn this work, we show that APX-SIM is P^QMA[log]-complete even when restricted\r\nto more physical Hamiltonians, obtaining as intermediate steps a variety of\r\nrelated complexity-theoretic results.\r\n  We first give a sequence of results which together yield P^QMA[log]-hardness\r\nfor APX-SIM on well-motivated Hamiltonians: (1) We show that for NP, StoqMA,\r\nand QMA oracles, a logarithmic number of adaptive queries is equivalent to\r\npolynomially many parallel queries. These equalities simplify the proofs of our\r\nsubsequent results. (2) Next, we show that the hardness of APX-SIM is preserved\r\nunder Hamiltonian simulations (a la [Cubitt, Montanaro, Piddock, 2017]). As a\r\nbyproduct, we obtain a full complexity classification of APX-SIM, showing it is\r\ncomplete for P, P^||NP, P^||StoqMA, or P^||QMA depending on the Hamiltonians\r\nemployed. (3) Leveraging the above, we show that APX-SIM is P^QMA[log]-complete\r\nfor any family of Hamiltonians which can efficiently simulate spatially sparse\r\nHamiltonians, including physically motivated models such as the 2D Heisenberg\r\nmodel.\r\n  Our second focus considers 1D systems: We show that APX-SIM remains\r\nP^QMA[log]-complete even for local Hamiltonians on a 1D line of 8-dimensional\r\nqudits. This uses a number of ideas from above, along with replacing the \"query\r\nHamiltonian\" of [Ambainis, CCC 2014] with a new \"sifter\" construction.","lang":"eng"}],"oa":"1","language":[{"iso":"eng"}],"_id":"13226","title":"Oracle complexity classes and local measurements on physical  Hamiltonians","citation":{"bibtex":"@inproceedings{Gharibian_Piddock_Yirka_2020, title={Oracle complexity classes and local measurements on physical  Hamiltonians}, booktitle={Proceedings of the 37th Symposium on Theoretical Aspects of Computer Science (STACS 2020)}, author={Gharibian, Sevag and Piddock, Stephen and Yirka, Justin}, year={2020}, pages={38} }","mla":"Gharibian, Sevag, et al. “Oracle Complexity Classes and Local Measurements on Physical  Hamiltonians.” <i>Proceedings of the 37th Symposium on Theoretical Aspects of Computer Science (STACS 2020)</i>, 2020, p. 38.","ieee":"S. Gharibian, S. Piddock, and J. Yirka, “Oracle complexity classes and local measurements on physical  Hamiltonians,” in <i>Proceedings of the 37th Symposium on Theoretical Aspects of Computer Science (STACS 2020)</i>, 2020, p. 38.","short":"S. Gharibian, S. Piddock, J. Yirka, in: Proceedings of the 37th Symposium on Theoretical Aspects of Computer Science (STACS 2020), 2020, p. 38.","ama":"Gharibian S, Piddock S, Yirka J. Oracle complexity classes and local measurements on physical  Hamiltonians. In: <i>Proceedings of the 37th Symposium on Theoretical Aspects of Computer Science (STACS 2020)</i>. ; 2020:38.","chicago":"Gharibian, Sevag, Stephen Piddock, and Justin Yirka. “Oracle Complexity Classes and Local Measurements on Physical  Hamiltonians.” In <i>Proceedings of the 37th Symposium on Theoretical Aspects of Computer Science (STACS 2020)</i>, 38, 2020.","apa":"Gharibian, S., Piddock, S., &#38; Yirka, J. (2020). Oracle complexity classes and local measurements on physical  Hamiltonians. <i>Proceedings of the 37th Symposium on Theoretical Aspects of Computer Science (STACS 2020)</i>, 38."},"type":"conference","page":"38","date_updated":"2023-10-09T04:17:41Z","publication":"Proceedings of the 37th Symposium on Theoretical Aspects of Computer Science (STACS 2020)","department":[{"_id":"623"},{"_id":"7"}],"author":[{"last_name":"Gharibian","full_name":"Gharibian, Sevag","orcid":"0000-0002-9992-3379","id":"71541","first_name":"Sevag"},{"last_name":"Piddock","full_name":"Piddock, Stephen","first_name":"Stephen"},{"last_name":"Yirka","full_name":"Yirka, Justin","first_name":"Justin"}],"year":"2020","user_id":"71541","main_file_link":[{"open_access":"1","url":"https://arxiv.org/abs/1909.05981"}],"publication_status":"published"}