Special CM Seminar, Timon Hilker, Max Planck, "Spin resolved microscopy of doped Hubbard chains"

Thu, Jun 22, 2017, 10:00 am

The doping of an antiferromagnet can lead to complex physics related to high temperature superconductivity. In one dimension, however, the competition between spin and density sectors is largely absent due to the separation of the spin and density modes at low energy.

A quantum gas microscope for ultracold fermions in optical lattices allows for the study of such systems with a unique control over kinetic energy, interactions and doping. A challenge has been to reach the required temperature for spin order and to measure the antiferromagnetic correlations with cold atoms.

I will present our direct, single-atom resolved detection of antiferromagnetic correlations over several sites in spin-1/2 Hubbard chains [1]. Upon doping the correlations seem to decrease. With our full access to the spin and density distribution we can directly measure three-point spin-hole-spin correlations and thus confirm that a hole in 1d only acts as a domain boundary of the spin-sector [2]. This is a direct consequence of the phenomenon of spin-charge separation and it allows to reveal the full correlations with non-local string operators [3].

Our technique can be extended to measure spin-charge separation dynamically and it will allow to study the complex interplay between magnetic order and density fluctuations in higher dimensions.

1. M. Boll et al. Science 353, 1257–1260 (2016).
2. T. A. Hilker et al. arXiv: 1702.00642 (2017).
3. M. Den Nijs & K. Rommelse Phys. Rev. B 40, 4709–4734 (1989)

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