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Department of Physics > LS Grifoni > AG Grifoni

Welcome to the homepage of the Quantum Transport and Dissipation group!

We are a theoretical group interested in the dynamical properties (transient and stationary) of open quantum systems out-of-equilibrium. These include on the one hand quantum transport properties of hybrid nanojunctions, molecular systems in STM configuration or complex quantum dots. On the other hand, the dissipative dynamics of (effective) quantum particles interacting with a surroundings. In recent years we have developed a many-body theory of quantum transport based on the reduced density matrix approach, which we have applied to investigate transport in carbon nanotube based nanojunctions and molecules. Also, we have used non-perturbative field theory approaches to investigate strongly correlated systems in the Kondo regime and interacting one-dimensional systems. Path integral approaches have recently been used to investigate decoherence and relaxation properties of superconducting qubits interacting with an electromagnetic environment.

Latest News

Analytical spectrum and the sparsity of Majorana zero modes in the topological phase diagram of the finite Kitaev chain

Unraveling a concealed resonance by multiple Kondo transitions in a quantum dot

Im Gedenken an Prof. Dr. Gustav Obermair

Mit großen Bedauern haben wir die Nachricht vom Tode Professor Dr. Gustav Obermairs erfahren. Prof. Obermair hatte über dreißig Jahre den Lehrstuhl für Theoretische Physik inne und war maßgeblich am Aufbau der Fakultät für Physik beteiligt. Von Oktober 1971 bis September 1973 stand er als Rektor an der Spitze der Universität Regensburg.

Unser Mitgefühl gilt seiner Familie!

Transverse profile and three-dimensional spin canting of a Majorana state in carbon nanotubes

Paper in Physical Review B

Transmission spectra of an ultrastrongly coupled qubit-dissipative resonator system

Figure (a) Scheme of the setup analyzed. A flux qubit, probed through a transmission line, is coupled to a resonator, the harmonic oscillator of frequency Ω . The latter is in turn in contact with an Ohmic heat bath. The incoming probe field is scattered at the qubit position, resulting in a transmitted and a reflected field. (b) Mapping to the spin-boson model. The harmonic bath is described by the structured effective spectral density of equation, with effective coupling α.

Paper in Journal of Statistical Mechanics

"Maßgeschneiderte Wellen" sorgen für starken Stromfluss Regensburger Physiker entwickeln Methode zur Kontrolle des Elektronensystems in Kohlenstroff-Nanoröhren

Paper in Physical Review Letters
Pressemitteilung in Mitteilungen der Universität Regensburg

Was wäre, wenn Schrödingers tote Katze mit einer lebendigen interferierte?

Paper in Nature Communications
Pressemitteilung in idw-Informationsdienst Wissenschaft

Probing the strongly driven spin-boson model in asuperconducting quantum circuit

Paper in Nature Communications

Coherent population trapping by dark state formation in a carbon nanotube quantum dot

Paper in Nature Communications

Majorana quasiparticles in semiconducting carbon nanotubes

Paper in Physical Review B

Topology and zero energy edge states in carbon nanotubes with superconducting pairing

Paper in Physical Review B

Apparent Reversal of Molecular Orbitals Reveals Entanglement

Paper in Physical Review Letters

Boundary effects and correlations in one-dimensional systems

Workshop: Milena Grifoni (Univ. Regensburg) and Wataru Izumida (Tohoku Univ.)