arXiv subjects

Pascal Degiovanni

Publications and source records attributed to Pascal Degiovanni.

21 records · Page 2Linked to original sources

arXiv2005

Nonstationary dephasing of two level systems

We investigate the influence of nonstationary 1/f^mu noise, produced by interacting defects, on a quantum two-level system. Adopting a simple phenomenological model for this noise we describe exactly the corresponding dephasing in various regimes. The nonstationarity and pronounced non-Gaussian features of this noise induce new anomalous dephasing scenarii. Beyond a history-dependent critical coupling strength the dephasing time exhibits a strong dependence on the age of the noise and the decay of coherence is not exponential.

cond-mat.mes-hall↗

arXiv2004

Quantum impurity approach to a coupled qubit problem

We consider a system of two qubits at the ends of a finite length 1D cavity. This problem is mapped onto the double-Kondo model which is also shown to describe the low energy physics of a finite length quantum wire with resonant levels at its ends. At the Toulouse point the ground state energy and the average populations and correlations of the qubits or resonant levels at zero temperature are computed. These results show that the effective interactions between the qubits or resonant levels can be used to probe their associated Kondo length scale.

cond-mat.mes-hall↗

arXiv2003

Charge and currents distribution in graphs

We consider graphs made of one-dimensional wires connected at vertices, and on which may live a scalar potential. We are interested in a scattering situation where such a network is connected to infinite leads. We study the correlations of the charge in such graphs out of equilibrium, as well as the distribution of the currents in the wires, inside the graph. These quantities are related to the scattering matrix of the graph. We discuss the case where the graph is weakly connected to the wires.

cond-mat.mes-hall↗