Related papers: Coherent quantum ratchets driven by tunnel oscilla…
We investigate experimentally a deterministic underdamped Josephson vortex ratchet -- a fluxon-particle moving along a Josephson junction in an asymmetric periodic potential. By applying a sinusoidal driving current one can compel the…
Current fluctuations can provide additional insight into quantum transport in mesoscopic systems. The present work is carried out for the fluctuation properties of transport through a pair of coupled quantum dots which are connected with…
We report shot noise spectroscopy on a semiconductor quantum dot in a cotunneling regime. The DC conductance measurements show clear signatures of both elastic and inelastic cotunneling transport inside a Coulomb diamond. We observed…
We analyze the real-time dynamics of a quantum two-state system in the presence of nonequilibrium quantum fluctuations. The latter are generated by a coupling of the two-state system to a single electronic level of a quantum dot which…
We report measurements of the cross-correlation between current noise fluctuations in two capacitively coupled quantum dots in the Coulomb blockade regime. The sign of the cross-spectral density is found to be tunable by gate voltage and…
We study the current and the associated noise for the transport through a two-site molecule driven by an external oscillating field. Within a high-frequency approximation, the time-dependent Hamiltonian is mapped to a static one with…
In this paper, we present theoretical investigation of the zero-frequency shot noise spectra in electron tunneling through an interacting quantum dot connected to two ferromagnetic leads with possibility of spin-flip scattering between the…
We investigate the transport properties of a new class of ratchets. The device is constructed by applying an ac voltage to the metallic single electron tunneling transistor, and a net transport current is induced by the time-dependent…
We carry out a detailed analysis of coherent resonant tunneling through two coupled quantum dots (CQD) in a parallel arrangement in the weak tunneling limit. We establish a set of quantum rate equations (QREs) in terms of the…
Based on Keldysh non-equilibrium Green function method, we have investigated spin current production in a hybrid T-shaped device, consisting of a central quantum dot connected to the leads and a side dot which only couples to the central…
We study the noise induced transport of an overdamped Brownian particle in frictional ratchet systems in the presence of external Gaussian white noise fluctuations. The analytical expressions for current and diffusion coefficient are…
The quantum ratchet effect in fully chaotic systems is approached by studying, for the first time, \emph{statistical} properties of the ratchet current over well-defined sets of initial states. Natural initial states in a semiclassical…
We consider the ratchet dynamics in a $\mathcal{PT}$-symmetric Floquet quantum system with symmetric temporal (harmonic) driving. In the exact $\mathcal{PT}$ phase, for a finite number of resonant frequencies, we show that the long-lasting…
We report the observation of the ratchet effect for a relativistic flux quantum trapped in an annular Josephson junction embedded in an inhomogeneous magnetic field. In such a solid state system mechanical quantities are proportional to…
We consider a double quantum dot coupled to two normal leads and one superconducting lead, modeling the Cooper pair beam splitter studied in two recent experiments. Starting from a microscopic Hamiltonian we derive a general expression for…
We propose and study a novel way to produce a DC transport of vortices when applying an AC electrical current to a sample. Specifically, we study superconductors with a graduated random pinning density, which transports interacting vortices…
We study current fluctuations in tunnel junctions driven by a voltage source. The voltage is applied to the tunneling element via an impedance providing an electromagnetic environment of the junction. We use circuit theory to relate the…
The Fano factor stability diagram of a C$_{3v}$ symmetric triangular quantum dot is analysed for increasing electron fillings $N$. At low filling, conventional Poissonian and sub-Poissonian behavior is found. At larger filling, $N\ge 2$, a…
We investigate the nonlinear response of an anharmonic monostable quantum mechanical resonator to strong external periodic driving. The driving thereby induces an effective bistability in which resonant tunneling can be identified. Within…
The Coulomb drag phenomenon in a Coulomb-coupled double quantum dot system is revisited with a simple model that highlights the importance of simultaneous tunneling of electrons. Previously, cotunneling effects on the drag current in…