Search arXiv⌕ Search
Home/Archive/arXiv

arXiv · cond-mat/0412544

Fano resonances and decoherence in transport through quantum dots

S. Rotter·U. Kuhl·F. Libisch·J. Burgdoerfer·H. -J. Stoeckmann
View original source ↗Read source document ↗Export metadata ↓

Abstract

A tunable microwave scattering device is presented which allows the controlled variation of Fano line shape parameters in transmission through quantum billiards. We observe a non-monotonic evolution of resonance parameters that is explained in terms of interacting resonances. The dissipation of radiation in the cavity walls leads to decoherence and thus to a modification of the Fano profile. We show that the imaginary part of the complex Fano q-parameter allows to determine the absorption constant of the cavity. Our theoretical results demonstrate further that the two decohering mechanisms, dephasing and dissipation, are equivalent in terms of their effect on the evolution of Fano resonance lineshapes.

Explore related subjects

cond-mat.mes-hall

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

S. Rotter, U. Kuhl, F. Libisch, J. Burgdoerfer, H. -J. Stoeckmann. 2004-12-20. Fano resonances and decoherence in transport through quantum dots. https://doi.org/10.1016/j.physe.2005.05.030

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

KEEP EXPLORING

Related papers

arXiv2026

Gapped out-of-phase plasmon modes in alternating-twist multilayer graphene

We theoretically investigate the plasmon modes of alternating-twist multilayer graphene. In multilayer systems, interlayer coupling gives rise to distinctive plasmon modes, but calculations in moiré systems remain challenging due to their complex tunneling structures. Using the Kac-Murdock-Szegő Toeplitz formalism, we derive that the in-phase mode exhibits the conventional $\sqrt{q}$ behavior, while the out-of-phase modes acquire plasmon gaps determined by specific interband transitions between Dirac cones with different velocities in the long-wavelength limit. We demonstrate that these out-of-phase modes remain undamped in the weak Coulomb-interaction limit when the twist angle exceeds a critical value ($θ\gtrsim 2.75^\circ$ for the alternating-twist trilayer case), regardless of the carrier density as long as the low-energy effective Dirac Hamiltonian remains valid. Furthermore, we consider the effect of a perpendicular electric field, and demonstrate how plasmon modes can be tuned by a gate voltage.

cond-mat.mes-hall↗
arXiv2026

Optical properties of hydrogenated graphene superlattices

We investigate with first principles theoretical methods optical response accounting for excitonic effects of quasi-one dimensional monolithic arrays of graphene nanostripes -- two-dimensional graphene superlattices, where quasi-metallic and dielectric regions alternate by selective hydrogenation of graphene. It is shown that chemical engineering of the graphene surface can lead to strong and well-isolated absorption peaks in the far-infrared and possibly even terahertz frequencies. The band gap scaling suggests no excitonic insulators.

cond-mat.mes-hall↗
arXiv2026

Long-lived Laughlin pairs in a depleted quantum Hall edge channel

On-demand sources and mesoscopic beam splitters allow individual ballistic electrons to collide in depleted quantum Hall edge channels, where their unscreened Coulomb interaction acts as a strong, controllable nonlinearity. Theory suggests a more striking possibility: in a strong magnetic field, the same repulsion can drive quantized relative circulation, allowing two electrons to propagate together as a positive-energy Laughlin pair. The relevance of such pairs to experiment depends on lifetimes in realistic guiding potentials and on whether the proposed collision pathway to pair formation survives full two-dimensional dynamics. We develop a microscopic theory of quasibound Laughlin pairs using the physical two-electron Hamiltonian. For a general local electric-field gradient, we determine the dissociation threshold, number of quasibound states, and decay rates. Complex scaling and analytic tunneling theory show that lifetimes grow exponentially with pair energy above threshold. Applied to reported GaAs parameters, the theory indicates that existing devices may already support the lowest spin-polarized pair, with a lifetime estimate roughly two orders of magnitude longer than typical propagation times. We simulate a collision with the full finite-field Hamiltonian, providing both a framework for nonlinear two-electron quantum dynamics and evidence for Laughlin-pair formation in a representative two-electron collision. We use Husimi distributions and their zeros to visualize both quasibound resonances and transient collision states in phase space. These results place the preparation, propagation, and detection of repulsively paired electrons within reach of existing single-electron circuit technology. They identify kinematic stabilization under constrained one-dimensional propagation as a pairing mechanism that may extend to anyonic quantum Hall edge excitations.

cond-mat.mes-hall↗