Barbara Dietz

Sep 3, 2024 | link.aps.org | Dung Nguyen |Barbara Dietz

We study fluctuation properties in the energy spectra of finite-size honeycomb lattices—graphene billiards—subject to the Haldane-model on-site potential and next-nearest-neighbor tunneling at critical points, referred to as Haldane graphene billiards in the following. The billiards have the shapes of a rectangular billiard with integrable dynamics, one with chaotic dynamics, and one whose shape has, in addition, threefold rotational symmetry.

Mar 25, 2024 | link.aps.org | Weihua Zhang |Gabriel M. Lando |Barbara Dietz |Sergej Flach

We study the disorder-induced crossover between the two recently discovered thermalization slowing-down universality classes, characterized by long- and short-range coupling, in classical unitary-circuit maps close to integrability. We compute Lyapunov spectra, which display qualitatively distinct features depending on whether the proximity to the integrable limit is short or long range. For sufficiently small nonlinearity, translationally invariant systems fall into the long-range class.

Oct 11, 2023 | link.aps.org | Xiaodong Zhang |Weihua Zhang |Jiongning Che |Barbara Dietz

Figure 4Two-point correlation functions of the S-matrix elements for a≠b in the frequency ranges indicated in the panels. Shown are the results for the cavity SB1 (black) and SB2 (red), the exact analytical results deduced from Eq. (1) with Ĥ replaced by Ĥ1→2(ξ) (turquoise), and the results obtained from Monte Carlo simulations for the S matrix, given by Eq. (1), with Ĥ replaced by Ĥ0→2(λ) (orange).

Oct 10, 2023 | link.aps.org | Weihua Zhang |Barbara Dietz

Abstract We report on the realization of a graphene billiard with a fourfold rotational symmetry, which has the shape of a billiard with chaotic classical dynamics. The eigenstates are separated according to their transformation properties under rotation by π2 into four symmetry classes.

May 6, 2023 | mdpi.com | Barbara Dietz

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