Learning a compass spin model with neural network quantum states. (7th January 2022)

• Record Type: Journal Article
• Authors: Zou, Eric; Long, Erik; Zhao, Erhai
• Is Part Of: Journal of physics. Volume 34:Number 12(2022)
• Publication Date: 2022-01-07
• Subjects: frustrated quantum spin models -- neural network quantum states -- machine learning -- numerical many-body algorithms; Condensed matter -- Periodicals; Matière condensée -- Périodiques; Vaste stoffen; Vloeistoffen; Natuurkunde; Electronic journals; Computer network resources; 530.4105
• DOI: 10.1088/1361-648X/ac43ff
• Languages: English
• ISSNs: 0953-8984

Abstract

Abstract: Neural network quantum states provide a novel representation of the many-body states of interacting quantum systems and open up a promising route to solve frustrated quantum spin models that evade other numerical approaches. Yet its capacity to describe complex magnetic orders with large unit cells has not been demonstrated, and its performance in a rugged energy landscape has been questioned. Here we apply restricted Boltzmann machines (RBMs) and stochastic gradient descent to seek the ground states of a compass spin model on the honeycomb lattice, which unifies the Kitaev model, Ising model and the quantum 120° model with a single tuning parameter. We report calculation results on the variational energy, order parameters and correlation functions. The phase diagram obtained is in good agreement with the predictions of tensor network ansatz, demonstrating the capacity of RBMs in learning the ground states of frustrated quantum spin Hamiltonians. The limitations of the calculation are discussed. A few strategies are outlined to address some of the challenges in machine learning frustrated quantum magnets.