arXiv subjects

H. U. Baranger

Publications and source records attributed to H. U. Baranger.

24 records · Page 2Linked to original sources

arXiv1995

Coulomb Blockade of Tunneling Through a Double Quantum Dot

We study the Coulomb blockade of tunneling through a double quantum dot. The temperature dependence of the linear conductance is strongly affected by the inter-dot tunneling. As the tunneling grows, a crossover from temperature-independent peak conductance to a power-law suppression of conductance at low temperatures is predicted. This suppression is a manifestation of the Anderson orthogonality catastrophe associated with the charge re-distribution between the dots, which accompanies the tunneling of an electron into a dot. We find analytically the shapes of the Coulomb blockade peaks in conductance as a function of gate voltage.

cond-mat↗

arXiv1995

TUNNELING SPECTROSCOPY OF QUANTUM CHARGE FLUCTUATIONS IN THE COULOMB BLOCKADE

We present a theory of Coulomb blockade oscillations in tunneling through a pair of quantum dots connected by a tunable tunneling junction. The positions and amplitudes of peaks in the linear conductance are directly related, respectively, to the ground state energy and to the dynamics of charge fluctuations. We study analytically both strong and weak interdot tunneling. As the tunneling decreases, the period of the peaks doubles, as observed experimentally. In the strong tunneling limit, we predict a striking power law temperature dependence of the peak amplitudes.

cond-mat↗

arXiv1995

SCATTERING INVOLVING PROMPT AND EQUILIBRATED COMPONENTS, INFORMATION THEORY, AND CHAOTIC QUANTUM DOTS

We propose an information-theoretic statistical model to describe the universal features of those chaotic scattering processes characterized by a prompt and an equilibrated component. The model, introduced in the past in nuclear physics, incorporates the average value of the scattering matrix to describe the prompt processes, and satisfies the requirements of flux conservation, causality, and ergodicity. We show that the model successfully describes electronic transport through chaotic quantum dots. The predicted distribution of the conductance may show a remarkable two-peak structure.

cond-mat↗

arXiv1994

Tunneling into a Two-Dimensional Electron Liquid in a Weak Magnetic Field

We study the spectral density function of a two-dimensional electron liquid in a weak magnetic field, the filling factor $ν\gg 1$. A hydrodynamic model for low-energy excitations of the liquid is developed. It is found that even at $ν\gg 1$ the density of states exhibits a gap at low energies. Its width $2E_0$ depends on the strength of interaction only logarithmically, $2E_0=(\hbarω_c/ν)\ln (νe^2/\varepsilon\hbar v_F)$. The effects of temperature and disorder on the density of states are discussed.

cond-mat↗

arXiv1994

Weak-Localization in Chaotic Versus Non-Chaotic Cavities: A Striking Difference in the Line Shape

We report experimental evidence that chaotic and non-chaotic scattering through ballistic cavities display distinct signatures in quantum transport. In the case of non-chaotic cavities, we observe a linear decrease in the average resistance with magnetic field which contrasts markedly with a Lorentzian behavior for a chaotic cavity. This difference in line-shape of the weak-localization peak is related to the differing distribution of areas enclosed by electron trajectories. In addition, periodic oscillations are observed which are probably associated with the Aharonov-Bohm effect through a periodic orbit within the cavities.

cond-mat↗

arXiv1992

Weak-Localization and Integrability in Ballistic Cavities

We demonstrate the existence of an interference contribution to the average magnetoconductance, G(B), of ballistic cavities and use it to test the semiclassical theory of quantum billiards. G(B) is qualitatively different for chaotic and regular cavities, an effect explained semiclassically by the differing classical distribution of areas. The magnitude of G(B) is poorly explained by the semiclassical theory of coherent backscattering (elastic enhancement factor)-- correlations beyond time-reversed pairs of trajectories must be included-- but is in agreement with random matrix theory.

cond-mat↗