Dissipative quantum North-East-Center model: Steady-state phase diagram, universality and nonergodic dynamics, by Pietro Brighi, Alberto Biella
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SciPost Physics Home Authoring Refereeing Submit a manuscript About Dissipative quantum North-East-Center model: Steady-state phase diagram, universality and nonergodic dynamics Pietro Brighi, Alberto Biella SciPost Phys. 20, 019 (2026) · published 22 January 2026 doi: 10.21468/SciPostPhys.20.1.019 pdf BiBTeX RIS Submissions/Reports Abstract In this work we study the dissipative quantum North-East-Center (NEC) model: a two-dimensional spin-1/2 lattice subject to chiral, kinetically constrained dissipation and coherent quantum interactions. This model combines kinetic constraints and chirality at the dissipative level, implementing local incoherent spin flips conditioned by an asymmetric majority-vote rule. Through a cluster mean-field approach, we determine the steady-state phase diagram of the NEC model under different Hamiltonians, consistently revealing the emergence of two distinct phases, bistable and normal, across all cases considered. We further investigate the stability of the steady-state with respect to inhomogeneous fluctuations in both phases, showing the emergence of instabilities at finite wavevectors in the proximity of the phase transition. Next, we study the nonergodicity of the model in the bistable phase. We characterize the dynamics of minority islands of spins surrounded by a large background of spins pointing in the opposite direction. We show that in the bistable phase, the minority islands are always reabsorbed by the surrounding at a constant velocity, irrespectively of their size. Finally, we propose and numerically benchmark an equation of motion for the reabsorption velocity of the islands where thermal and quantum fluctuations act independently at linear order. × TY - JOURPB - SciPost FoundationDO - 10.21468/SciPostPhys.20.1.019TI - Dissipative quantum North-East-Center model: Steady-state phase diagram, universality and nonergodic dynamicsPY - 2026/01/22UR - https://scipost.org/SciPostPhys.20.1.019JF - SciPost PhysicsJA - SciPost Phys.VL - 20IS - 1SP - 019A1 - Biella, AlbertoAU - Brighi, PietroAB - In this work we study the dissipative quantum North-East-Center (NEC) model: a two-dimensional spin-1/2 lattice subject to chiral, kinetically constrained dissipation and coherent quantum interactions. This model combines kinetic constraints and chirality at the dissipative level, implementing local incoherent spin flips conditioned by an asymmetric majority-vote rule. Through a cluster mean-field approach, we determine the steady-state phase diagram of the NEC model under different Hamiltonians, consistently revealing the emergence of two distinct phases, bistable and normal, across all cases considered. We further investigate the stability of the steady-state with respect to inhomogeneous fluctuations in both phases, showing the emergence of instabilities at finite wavevectors in the proximity of the phase transition. Next, we study the nonergodicity of the model in the bistable phase. We characterize the dynamics of minority islands of spins surrounded by a large background of spins pointing in the opposite direction. We show that in the bistable phase, the minority islands are always reabsorbed by the surrounding at a constant velocity, irrespectively of their size. Finally, we propose and numerically benchmark an equation of motion for the reabsorption velocity of the islands where thermal and quantum fluctuations act independently at linear order.ER - × @Article{10.21468/SciPostPhys.20.1.019, title={{Dissipative quantum North-East-Center model: Steady-state phase diagram, universality and nonergodic dynamics}}, author={Pietro Brighi and Alberto Biella}, journal={SciPost Phys.}, volume={20}, pages={019}, year={2026}, publisher={SciPost}, doi={10.21468/SciPostPhys.20.1.019}, url={https://scipost.org/10.21468/SciPostPhys.20.1.019},} Ontology / Topics See full Ontology or Topics database. Open quantum systems Quantum many-body systems Quantum spin chains Relaxation dynamics Two-dimensional systems Authors / Affiliations: mappings to Contributors and Organizations See all Organizations. 1 Alberto Biella, 2 3 4 Pietro Brighi 1 Universität Wien / University of Vienna 2 Università degli Studi di Trento / University of Trento 3 Istituto Nazionale di Ottica [INO] 4 INFN Trento Institute for Fundamental Physics And Applications [TIFPA] Funders for the research work leading to this publication Austrian Science Fund (FWF) (through Organization: Fonds zur Förderung der wissenschaftlichen Forschung / FWF Austrian Science Fund [FWF]) Ministero dell’Istruzione, dell’Università e della Ricerca (MIUR) (through Organization: Ministero dell'Istruzione, dell'Università e della Ricerca / Ministry of Education, Universities and Research [MIUR]) Provincia Autonoma di Trento