Deconfined quantum critical point in one dimension

Kavli Affiliate: Shenghan Jiang

| First 5 Authors: Brenden Roberts, Shenghan Jiang, Olexei I. Motrunich, ,

| Summary:

We perform a numerical study of a spin-1/2 model with $mathbb{Z}_2 times
mathbb{Z}_2$ symmetry in one dimension which demonstrates an interesting
similarity to the physics of two-dimensional deconfined quantum critical points
(DQCP). Specifically, we investigate the quantum phase transition between Ising
ferromagnetic and valence bond solid (VBS) symmetry-breaking phases. Working
directly in the thermodynamic limit using uniform matrix product states, we
find evidence for a direct continuous phase transition that lies outside of the
Landau-Ginzburg-Wilson paradigm. In our model, the continuous transition is
found everywhere on the phase boundary. We find that the magnetic and VBS
correlations show very close power law exponents, which is expected from the
self-duality of the parton description of this DQCP. Critical exponents vary
continuously along the phase boundary in a manner consistent with the
predictions of the field theory for this transition. We also find a regime
where the phase boundary splits, as suggested by the theory, introducing an
intermediate phase of coexisting ferromagnetic and VBS order parameters.
Interestingly, we discover a transition involving this coexistence phase which
is similar to the DQCP, being also disallowed by Landau-Ginzburg-Wilson
symmetry-breaking theory.

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