{"external_id":{"isi":["000605080300001"]},"publication_status":"published","license":"https://creativecommons.org/licenses/by/4.0/","oa":1,"language":[{"iso":"eng"}],"day":"05","publisher":"IOP Publishing","volume":2021,"year":"2021","_id":"9158","publication":"Journal of Statistical Mechanics: Theory and Experiment","article_number":"013101","date_updated":"2023-08-07T13:46:28Z","file":[{"success":1,"content_type":"application/pdf","date_created":"2021-02-19T14:04:40Z","file_size":1693609,"date_updated":"2021-02-19T14:04:40Z","checksum":"64e2aae4837790db26e1dd1986c69c07","creator":"dernst","file_name":"2021_JourStatMech_deNicola.pdf","access_level":"open_access","file_id":"9172","relation":"main_file"}],"acknowledgement":"S D N would like to thank M J Bhaseen, J Chalker, B Doyon, V Gritsev, A Lamacraft,\r\nA Michailidis and M Serbyn for helpful feedback and stimulating conversations. S D N\r\nacknowledges funding from the Institute of Science and Technology (IST) Austria, and\r\nfrom the European Union’s Horizon 2020 research and innovation program under the\r\nMarie Sk\blodowska-Curie Grant Agreement No. 754411. S D N also acknowledges funding\r\nfrom the EPSRC Center for Doctoral Training in Cross-Disciplinary Approaches to Non-\r\nEquilibrium Systems (CANES) under Grant EP/L015854/1. S D N is grateful to IST\r\nAustria for providing open access funding.","doi":"10.1088/1742-5468/abc7c7","issue":"1","ddc":["530"],"title":"Disentanglement approach to quantum spin ground states: Field theory and stochastic simulation","ec_funded":1,"status":"public","article_type":"original","has_accepted_license":"1","article_processing_charge":"No","user_id":"4359f0d1-fa6c-11eb-b949-802e58b17ae8","file_date_updated":"2021-02-19T14:04:40Z","keyword":["Statistics","Probability and Uncertainty","Statistics and Probability","Statistical and Nonlinear Physics"],"date_published":"2021-01-05T00:00:00Z","oa_version":"Published Version","date_created":"2021-02-17T17:48:46Z","month":"01","publication_identifier":{"issn":["1742-5468"]},"type":"journal_article","project":[{"grant_number":"754411","_id":"260C2330-B435-11E9-9278-68D0E5697425","name":"ISTplus - Postdoctoral Fellowships","call_identifier":"H2020"},{"name":"IST Austria Open Access Fund","_id":"B67AFEDC-15C9-11EA-A837-991A96BB2854"}],"abstract":[{"text":"While several tools have been developed to study the ground state of many-body quantum spin systems, the limitations of existing techniques call for the exploration of new approaches. In this manuscript we develop an alternative analytical and numerical framework for many-body quantum spin ground states, based on the disentanglement formalism. In this approach, observables are exactly expressed as Gaussian-weighted functional integrals over scalar fields. We identify the leading contribution to these integrals, given by the saddle point of a suitable effective action. Analytically, we develop a field-theoretical expansion of the functional integrals, performed by means of appropriate Feynman rules. The expansion can be truncated to a desired order to obtain analytical approximations to observables. Numerically, we show that the disentanglement approach can be used to compute ground state expectation values from classical stochastic processes. While the associated fluctuations grow exponentially with imaginary time and the system size, this growth can be mitigated by means of an importance sampling scheme based on knowledge of the saddle point configuration. We illustrate the advantages and limitations of our methods by considering the quantum Ising model in 1, 2 and 3 spatial dimensions. Our analytical and numerical approaches are applicable to a broad class of systems, bridging concepts from quantum lattice models, continuum field theory, and classical stochastic processes.","lang":"eng"}],"quality_controlled":"1","department":[{"_id":"MaSe"}],"citation":{"ista":"De Nicola S. 2021. Disentanglement approach to quantum spin ground states: Field theory and stochastic simulation. Journal of Statistical Mechanics: Theory and Experiment. 2021(1), 013101.","ama":"De Nicola S. Disentanglement approach to quantum spin ground states: Field theory and stochastic simulation. <i>Journal of Statistical Mechanics: Theory and Experiment</i>. 2021;2021(1). doi:<a href=\"https://doi.org/10.1088/1742-5468/abc7c7\">10.1088/1742-5468/abc7c7</a>","short":"S. De Nicola, Journal of Statistical Mechanics: Theory and Experiment 2021 (2021).","chicago":"De Nicola, Stefano. “Disentanglement Approach to Quantum Spin Ground States: Field Theory and Stochastic Simulation.” <i>Journal of Statistical Mechanics: Theory and Experiment</i>. IOP Publishing, 2021. <a href=\"https://doi.org/10.1088/1742-5468/abc7c7\">https://doi.org/10.1088/1742-5468/abc7c7</a>.","apa":"De Nicola, S. (2021). Disentanglement approach to quantum spin ground states: Field theory and stochastic simulation. <i>Journal of Statistical Mechanics: Theory and Experiment</i>. IOP Publishing. <a href=\"https://doi.org/10.1088/1742-5468/abc7c7\">https://doi.org/10.1088/1742-5468/abc7c7</a>","mla":"De Nicola, Stefano. “Disentanglement Approach to Quantum Spin Ground States: Field Theory and Stochastic Simulation.” <i>Journal of Statistical Mechanics: Theory and Experiment</i>, vol. 2021, no. 1, 013101, IOP Publishing, 2021, doi:<a href=\"https://doi.org/10.1088/1742-5468/abc7c7\">10.1088/1742-5468/abc7c7</a>.","ieee":"S. De Nicola, “Disentanglement approach to quantum spin ground states: Field theory and stochastic simulation,” <i>Journal of Statistical Mechanics: Theory and Experiment</i>, vol. 2021, no. 1. IOP Publishing, 2021."},"intvolume":"      2021","author":[{"last_name":"De Nicola","full_name":"De Nicola, Stefano","id":"42832B76-F248-11E8-B48F-1D18A9856A87","orcid":"0000-0002-4842-6671","first_name":"Stefano"}],"isi":1,"tmp":{"legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode","short":"CC BY (4.0)","image":"/images/cc_by.png","name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)"}}