Searcharxiv⌕ Search
Home/Archive/arXiv

arXiv · cond-mat/0009010

Conductance Fluctuations of Generic Billiards: Fractal or Isolated?

L. Hufnagel·R. Ketzmerick·M. Weiss
View original source ↗Read source document ↗Export metadata ↓

Abstract

We study the signatures of a classical mixed phase space for open quantum systems. We find the scaling of the break time up to which quantum mechanics mimics the classical staying probability and derive the distribution of resonance widths. Based on these results we explain why for mixed systems two types of conductance fluctuat ions were found: quantum mechanics divides the hierarchically structured chaotic component of phase space into two parts - one yields fractal conductance fluctuations while the other causes isolated resonances. In general, both types appear together, but on different energy scales.

Explore related subjects

cond-mat.mes-hallnlin.CD

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

L. Hufnagel, R. Ketzmerick, M. Weiss. 2000-12-20. Conductance Fluctuations of Generic Billiards: Fractal or Isolated?. https://doi.org/10.1209/epl%2Fi2001-00309-6

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Computational quantum transport: a scattering approach perspective

This review is devoted to the different techniques that have been developed to compute the phase-coherent transport properties of quantum nanoelectronic systems connected to electrodes. Beside a review of the different algorithms proposed in the literature, we provide a comprehensive and pedagogical derivation of the two formalisms on which these techniques are based: the scattering approach and the (nonequilibrium) Green's function approach. We show that the scattering problem can be formulated as a system of linear equations and that different existing algorithms for solving this scattering problem amount to different sequences of Gaussian elimination. We explicitly prove the equivalence of the two formalisms. We discuss the stability and numerical complexity of the existing methods. The review ends with a selection of a few applications where numerical calculations were instrumental in shaping our understanding of the physics.

cond-mat.mes-hall↗
arXiv2026

Curvature-stabilized three-dimensional spiral states and local-field nucleation of skyrmions on spherical caps

The combination of polystyrene particles and multilayers with chiral interfacial interactions offers an interesting platform to study the interplay between topology, chirality, and curvature. Here, we investigate Pt/Co/Ta multilayers sputtered onto self-assembled polystyrene particles with a diameter of 919 nm, which show a magnetic reversal distinctly different from that of planar films. Using non-invasive scanning transmission X-ray microscopy and in-vacuum magnetic force microscopy (MFM) with low-moment tips, we observe maze domains in the planar films, whereas the curvilinear films host three-dimensional spiraling stripe states. Repeated scanning with a conventional higher-moment MFM tip ruptures these spirals into metastable skyrmions at the top of the particles. Micromagnetic simulations of spherical caps reveal that increasing curvature renders a single spiral stripe energetically favorable over an isolated skyrmion, and that this stabilization is predominantly of magnetostatic origin. Our results identify the spiral states as intrinsic to the curvilinear geometry and the skyrmions as metastable states nucleated by local magnetic fields, underlining the value of non-invasive imaging to distinguish intrinsic curvature effects from probe-induced magnetic textures.

cond-mat.mes-hall↗
arXiv2026

Coherent control of spinmons

In this work, we explore a hybrid qubit device where quantum information is encoded by quantum states of a transmon entangled with the spin of a trapped Andreev quasiparticle. We term such devices spinmons. We lift the spinmon Kramers degeneracy by introducing a Zeeman field and develop two routes for full qubit control via electrostatic gates and an AC flux drive, providing multiple directions for experimental implementations. Finally, we compute coherence times, verify the qubit robustness against flux, charge and gate voltage noise sources, and discuss the role of nuclear spin noise.

cond-mat.mes-hall↗