arXiv subjects

Friedemann Queißer

Publications and source records attributed to Friedemann Queißer.

2 recordsLinked to original sources

arXiv2026

Transport statistics and thermoelectric performance of Hofstadters butterfly

We investigate electrons subject to a magnetic field that may tunnel along a square lattice and additionally to two electronic leads. Using non-equilibrium Greens functions we evaluate the transmission and from that particle and energy currents and zero-frequency noise of the setup. We identify sweet spots for which the transmission reaches unity over broad frequency windows -- carried by topologically protected boundary modes that are quite robust against local fluctuations of on-site energies. These transmission plateaus can be exploited for the implementation robust current standards, clocks and thermoelectric devices.

cond-mat.mes-hall↗

arXiv2026

Exploring bosonic bound states with parallel reaction coordinates

Bound states are dissipation-resilient states that may emerge when quantum systems are strongly coupled to reservoirs with band gaps. We analyze an exactly solvable bosonic model for bound state existence and reproduce these results by a weak-coupling treatment of a supersystem composed of the original system and multiple reaction coordinates, which are individually representing small energy intervals of the reservoir spectral function. Within the perturbative supersystem treatment, the bound state stability results from its energy being inside the band gap. We discuss cases of multiple band gaps and also show that already in presence of weak interactions the bound state's lifetime is finite -- but can be increased by raising the system-reservoir coupling strength.

quant-ph↗