arXiv subjects

Eliot Heinrich

Publications and source records attributed to Eliot Heinrich.

6 recordsLinked to original sources

arXiv2026

Critical behaviors of magic and participation entropy at measurement induced phase transitions

We study the participation and stabilizer entropy of non-unitary quantum circuit dynamics, focusing on the critical line that separates the low-entanglement spin-glass phase and the paramagnetic phase. Along this critical line, the entanglement has a logarithmic scaling, which enables us to access the critical regime using large-scale matrix product state simulations with modest bond dimension. We find that both the participation entropy and stabilizer entropy exhibit critical slowing down: their saturation time scales linearly with the system size, in stark contrast to purely unitary dynamics, where saturation occurs on logarithmic time scales. In addition, we study bipartite participation and stabilizer mutual information, and find that it shows similar scaling behavior to the entanglement entropy. Finally, by analyzing the participation entropy of several paradigmatic Clifford circuits, we identify similar slow dynamical behavior near their respective critical points.

quant-ph↗

arXiv2024

Measurement induced phase transitions in quantum raise and peel models

We present a quantum circuit model which emulates the interface growth of the classical raise-and-peel model. Our model consists of Clifford unitary gates interspersed with projective measurements, applied according to prescribed feedback rules. We numerically find via large-scale simulations that, depending on the feedback rules, the system may undergo several measurement-induced entanglement transitions, including continuous transitions within a universality class not previously observed in hybrid random Clifford systems as well as a first-order transition.

quant-ph↗

arXiv2024

Magnetic structure of EuCd$_2$Sb$_2$ single-crystal thin-film

We investigate the magnetic order in single crystalline EuCd$_2$Sb$_2$ thin films using a combined theoretical and experimental approach. Resonant elastic x-ray scattering experiments reveal a sharp magnetic peak at $q = (0, 0, \frac{1}{2})$ below $T_N = 7.2$ K, indicative of interlayer antiferromagnetic ordering. Additionally, we observe a weak diffuse magnetic signal centered at $q = (0, 0, 1)$ that persists above $T_N$, up to $T_C \sim 11$ K. Our Monte-Carlo simulations of a classical spin model approximation of the Eu magnetic sublattice demonstrate that the diffuse signal can arise from ferromagnetic coupling in the top few layers due to surface oxidation. On the other hand, the bulk of the sample exhibits antiferromagnetic coupling between layers. Finally, our fit of the model parameters to the magnetic ordering temperatures, shed light on the exchange couplings that are key in stabilizing the observed composite magnetic order.

cond-mat.mtrl-sci↗

arXiv2022

Topological magnetic phase transition in Eu-based A-type antiferromagnets

Recently, a colossal magnetoresistance (CMR) was observed in EuCd$_2$P$_2$ -- a compound that does not fit the conventional mixed-valence paradigm. Instead, experimental evidence points at a resistance driven by strong magnetic fluctuations within the two-dimensional ($2d$) ferromagnetic (FM) planes of the layered antiferromagnetic (AFM) structure. While the experimental results have not yet been fully understood, a recent theory relates the CMR to a topological vortex-antivortex unbinding, i.e., Berezinskii-Kosterlitz-Thouless (BKT), phase transition. Motivated by these observations, in this work we explore the magnetic phases hosted by a microscopic classical magnetic model for EuCd$_2$P$_2$, which easily generalizes to other Eu A-type antiferromagnetic compounds. Using Monte Carlo techniques to probe the specific heat and the helicity modulus, we show that our model can exhibit a vortex-antivortex unbinding phase transition. We find that this phase transition displays the same sensitivity to in-plane magnetization, interlayer coupling, and easy-plane anisotropy that is observed experimentally in the CMR signal, providing qualitative numerical evidence that the effect is related to a magnetic BKT transition.

cond-mat.mes-hall↗

arXiv2022

Spin interactions and topological magnonics in chromium trihalide CrClBrI

The discovery of spontaneous magnetism in van der Waal (vdW) magnetic monolayers has opened up an unprecedented platform for investigating magnetism in purely two-dimensional systems. Recently, it has been shown that the magnetic properties of vdW magnets can be easily tuned by adjusting the relative composition of halides. Motivated by these experimental advances, here we derive a model for a trihalide CrClBrI monolayer from symmetry principles and we find that, in contrast to its single-halide counterparts, it can display highly anisotropic nearest- and next-to-nearest neighbor Dzyaloshinskii-Moriya and Heisenberg interactions. Depending on the parameters, the DM interactions are responsible for the formation of exotic chiral spin states, such as skyrmions and spin cycloids, as shown by our Monte Carlo simulations. Focusing on a ground state with a two-sublattice unit cell, we find spin-wave bands with nonvanishing Chern numbers. The resulting magnon edge states yield a magnon thermal Hall conductivity that changes sign as function of temperature and magnetic field, suggesting chromium trihalides as a candidate for testing topological magnon transport in two-dimensional noncollinear spin systems.

cond-mat.mes-hall↗

arXiv2019

Quantum and thermal fluctuations of a thin elastic plate

We consider a Hamiltonian description of the vibrations of a clamped, elastic circular plate. The Hamiltonian of this system features a potential energy with two distinct contributions: one that depends on the local mean curvature of the plate, and a second that depends on its Gaussian curvature. We quantize this model using a complete, orthonormal set of eigenfunctions for the clamped, vibrating plate. The resulting quanta are the flexural phonons of the thin circular plate. As an application, we use this quantized description to calculate the fluctuations in displacement of the plate for arbitrary temperature. We compare the fluctuation profile with that from an elastic membrane under tension. At low temperature, we find that while both profiles have a circular ring of local maxima, the ring in the membrane profile is much more pronounced and sharper. We also note that with increasing temperature the plate profile develops two additional rings of extrema.

cond-mat.mes-hall↗