Domain-wall confinement and dynamics in a quantum simulator

• Published in: Nature physics Vol. 17; no. 6; pp. 742 - 747
• Main Authors: Tan, W. L., Becker, P., Liu, F., Pagano, G., Collins, K. S., De, A., Feng, L., Kaplan, H. B., Kyprianidis, A., Lundgren, R., Morong, W., Whitsitt, S., Gorshkov, A. V., Monroe, C.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.06.2021; Nature Publishing Group; Nature Publishing Group (NPG)
• Subjects: 639/766/119; 639/766/36; 639/766/483/3926; Atomic; Chains; Classical and Continuum Physics; Complex Systems; Condensed Matter Physics; Confinement; Domain walls; Elementary excitations; Excitation; Ising model; Magnetic domains; Mathematical and Computational Physics; Mesons; Molecular; Optical and Plasma Physics; Particle physics; Physics; Physics and Astronomy; Quarks; Simulation; Simulators; Theoretical; Thermalization (energy absorption)
• ISSN: 1745-2473; 1745-2481
• DOI: 10.1038/s41567-021-01194-3

Particles subject to confinement experience an attractive potential that increases without bound as they separate. A prominent example is colour confinement in particle physics, in which baryons and mesons are produced by quark confinement. Confinement can also occur in low-energy quantum many-body systems when elementary excitations are confined into bound quasiparticles. Here we report the observation of magnetic domain-wall confinement in interacting spin chains with a trapped-ion quantum simulator. By measuring how correlations spread, we show that confinement can suppress information propagation and thermalization in such many-body systems. We quantitatively determine the excitation energy of domain-wall bound states from the non-equilibrium quench dynamics. We also study the number of domain-wall excitations created for different quench parameters, in a regime that is difficult to model with classical computers. This work demonstrates the capability of quantum simulators for investigating high-energy physics phenomena, such as quark collision and string breaking. Long-range Ising interactions present in one-dimensional spin chains can induce a confining potential between pairs of domain walls, slowing down the thermalization of the system. This has now been observed in a trapped-ion quantum simulator.