Spin-Charge Separation in Atomic Chains

August 11, 2017

Fig. 1. Experimental spin and density-resolved image of a single, slightly doped Hubbard chain after a local Stern-Gerlach-like detection. The reconstructed chain is shown below the picture.
From: Hilker, et al. (see below). Reprinted by permission from AAAS ©2017.

Strongly interacting electrons lined up along a string can experience the so-called spin-charge separation, where the electrons "split" into effective carriers of spin and charge, which then move independently. This phenomenon has been observed, somewhat indirectly, in solids. A team of scientists from the Max Planck Institute of Quantum Optics, Harvard (including postdoc Fabian Grusdt and Prof. Eugene Demler), and Ludwig Maximilian University of Munich reported observing the spin-charge separation in a direct way. The researchers used a one-dimensional (1D) array of cold atoms, playing the role of electrons, whose degrees of freedom of spin and charge can be monitored using a fermionic quantum gas microscope. Empty sites in the 1D lattice moved freely without disturbing the underlying antiferromagnetic order.

In the next step the scientists plan to extend the method to two-dimensional systems. Here the interaction between holes and magnetic correlations is by far more complex. It could lead to the detection of exotic many-body phases that might be responsible for the occurrence of high-temperature superconductivity.

Read "Quantum magnets doped with holes" on phys.org, as well as the Report in Science: T.A. Hilker, G. Salomon, F. Grusdt, A. Omran, M. Boll, E. Demler, I. Bloch, C. Gross, "Revealing hidden antiferromagnetic correlations in doped Hubbard chains via string correlators," Science 357 (2017) https://doi.org/10.1126/science.aam8990.