Digital quantum simulation of the statistical mechanics of a frustrated magnet

• Published in: Nature communications 2012-06, Vol.3 (1), p.880-880, Article 880
• Main Authors: Zhang, Jingfu, Yung, Man-Hong, Laflamme, Raymond, Aspuru-Guzik, Alán, Baugh, Jonathan
• Format: Article
• Language: English
• Subjects: 639/638/440/951; 639/766/119/997; 639/766/483/481; Humanities and Social Sciences; Magnets; multidisciplinary; Quantum Theory; Science; Science (multidisciplinary)
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/ncomms1860

Many problems of interest in physics, chemistry and computer science are equivalent to problems defined on systems of interacting spins. However, most such problems require computational resources that are out of reach with classical computers. A promising solution to overcome this challenge is quantum simulation. Several 'analogue' quantum simulations of interacting spin systems have been realized experimentally, where ground states were prepared using adiabatic techniques. Here we report a 'digital' quantum simulation of thermal states; a three-spin frustrated magnet was simulated using a nuclear magnetic resonance quantum information processor, and we were able to explore the phase diagram of the system at any simulated temperature and external field. These results help to identify the challenges for performing quantum simulations of physical systems at finite temperatures, and suggest methods that may be useful in simulating thermal open quantum systems. Geometrically frustrated spin systems are a class of statistical mechanical models that have received widespread attention, especially in condensed matter physics. This study experimentally demonstrates a quantum information processor that can simulate the behaviour of such frustrated spin system.