Microscopic spinon-chargon theory of magnetic polarons in the t−J model

Abstract

The interplay of spin and charge degrees of freedom, introduced by doping mobile holes into a Mott insulator with strong anti-ferromagnetic (AFM) correlations, is at the heart of strongly correlated matter such as high-Tc cuprate superconductors. Here we capture this interplay in the strong coupling regime and propose a trial wavefunction of mobile holes in an AFM. Our method provides a microscopic justification for a class of theories which describe doped holes moving in an AFM environment as meson-like bound states of spinons and chargons. We discuss a model of such bound states from the perspective of geometric strings, which describe a fluctuating lattice geometry introduced by the fast motion of the chargon. This is demonstrated to give rise to short-range hidden string order, signatures of which have recently been revealed by ultracold atom experiments. We present evidence for the existence of such short-range hidden string correlations also at zero temperature by performing numerical DMRG simulations. To test our microscopic approach, we calculate the ground state energy and dispersion relation of a hole in an AFM, as well as the magnetic polaron radius, and obtain good quantitative agreement with advanced numerical simulations at strong couplings. We discuss extensions of our analysis to systems without long range AFM order to systems with short-range magnetic correlations.

Correlator convolutional neural networks as an interpretable architecture for image-like quantum matter data

“…In the "frozen spin approximation" 26 , geometric string theory predicts that the motion of the holes simply displaces spins backwards along the path the hole takes. Hence the propagation of the doped hole will tend to produce a "wake" of parallel line segments of aligned spins in its trail (Fig.…”

Snapshot based characterization of particle currents and the Hall response in synthetic flux lattices

“…[23]. Here, perfect sampling refers to the fact that this scheme generates perfectly uncorrelated snapshots, without the need to account for additional equilibration or autocorrelation times, as in Markov chain Monte Carlo approaches [73][74][75]. For our results concerning the bosonic flux-ladder model, that will be presented later on, it is crucial to additionally account for the U (1) symmetry corresponding to the conservation of the particle number while generating snapshots from matrix-product states.…”

Exploration of doped quantum magnets with ultracold atoms

“…Recently new indications for the parton picture have been reported by advanced matrix product state (MPS) simulations [86,25,24]. Moreover, the string picture has been extended to include quantum fluctuations of the spin background [139] by introducing so-called geometric strings [87,86].…”

“…With the advent of quantum gas microscopes, which naturally probe the system in real space and time, this perspective has become directly accessible in experiments. Theoretical predictions for the real space correlations of a single hole with the spin background can now be confirmed experimentally [86,123,48]. With this perspective in mind, it becomes clear that quantum simulators, and in particular quantum gas microscopes, can go beyond reproducing the experimental results available in solid state electronic systems, but rather provide a complementary experimental platform with its own powerful toolbox.…”