arXiv subjects

Will Holdhusen

Publications and source records attributed to Will Holdhusen.

3 recordsLinked to original sources

arXiv2026

Classical Cellular Automaton for Measurement-Only Entanglement Transitions

We introduce a generalized classical long-range stochastic cellular automaton that exactly captures the entanglement dynamics and transitions of a measurement-only monitored quantum system. The corresponding quantum model consists of a one-dimensional qubit chain subject to competing single-site and long-range Bell measurements, with separations drawn from a power-law distribution. At every step of each trajectory, the state remains a tensor product of Bell pairs and unpaired qubits, with bipartite entanglement entropy fully encoded in a classical matching of the sites. This exact representation allows us to solve the dynamics analytically in several limits and to determine the steady-state scaling of the entanglement entropy. We find volume-law, fractal, and area-law regimes. Numerical results show that these regimes persist beyond the analytically solvable limit. Because Bell outcomes affect only Bell-state labels and not the matching, all subsystem entropies are outcome independent, avoiding the exponential cost of trajectory postselection.

quant-ph↗

arXiv2026

Symmetry-Protected Topological Phases in the Triangular Majorana-Hubbard Ladder

We uncover a family of symmetry-protected topological phases in a model of interacting Majorana fermions on triangular-lattice ladders. Included among these phases is one in which symmetry-protected topological order coexists with spontaneous symmetry breaking associated with an adiabatically evolving set of symmetries. Our results indicate a mechanism through which interactions among Majorana modes generate nontrivial symmetry-fractionalized orders. These phases may be realized in arrays of vortex-bound Majorana zero modes on the surface of topological superconductors.

cond-mat.str-el↗

arXiv2023

Emergent magnetic order in the antiferromagnetic Kitaev model with a [111] field

The Kitaev spin liquid, stabilized as the ground state of the Kitaev honeycomb model, is a paradigmatic example of a topological $\mathbb{Z}_2$ quantum spin liquid. The fate of the Kitaev spin liquid in presence of an external magnetic field is a topic of current interest due to experiments, which apparently unveil a $\mathbb{Z}_2$ topological phase in the so-called Kitaev materials, and theoretical studies predicting the emergence of an intermediate quantum phase of debated nature before the appearance of a trivial partially polarized phase. In this work, we employ hierarchical mean-field theory, an algebraic and numerical method based on the use of clusters preserving relevant symmetries and short-range quantum correlations, to investigate the quantum phase diagram of the antiferromagnetic Kitaev's model in a [111] field. By using clusters of 24 sites, we predict that the Kitaev spin liquid transits through two intermediate phases characterized by stripe and chiral order, respectively, before entering the trivial partially polarized phase, differing from previous studies. We assess our results by performing exact diagonalization and computing the scaling of different observables, including the many-body Chern number and other topological quantities, thus establishing hierarchical mean-field theory as a method to study topological quantum spin liquids.

cond-mat.str-el↗