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Papers by Ramón Aguado
AIP Conference Proceedings, 2005
ABSTRACT We study the current noise spectrum of charge qubits under transport conditions (double ... more ABSTRACT We study the current noise spectrum of charge qubits under transport conditions (double quantum dots and Cooper pair boxes) in a dissipative bosonic environment. We combine master equations with correlation functions in Laplace‐space to derive a noise formula for both weak and strong coupling to the bath. © 2005 American Institute of Physics
Europhysics Letters (epl), 1997
We develope a model to describe the transmission coefficient and tunneling current in the presenc... more We develope a model to describe the transmission coefficient and tunneling current in the presence of photon-electron coupling in a resonant diode. Our model takes into account multiphoton processes as well as the transitions between electronic states with different wave numbers. This is crutial to explain the experimental features observed in the tunneling current through a double barrier which cannot be reproduced with more simplified established models. According to our results, what experiments show in the current density are quantum photon-assisted features coming from multiphoton transitions which are not related with sample heating.
Physical Review B, 1996
We have analyzed the tunneling transmission probability and electronic current density through re... more We have analyzed the tunneling transmission probability and electronic current density through resonant heterostructures in the presence of an external electromagnetic field. In this work, we compare two different models for a double barrier : In the first case the effect of the external field is taken into account by spatially dependent AC voltages and in the second one the electromagnetic field is described in terms of a photon field that irradiates homogeneously the whole sample. While in the first description the tunneling takes place mainly through photo sidebands in the case of homogeneous illumination the main effective tunneling channels correspond to the coupling between different electronic states due to photon absorption and emission. The difference of tunneling mechanisms between these configurations is strongly reflected in the transmission and current density which present very different features in both cases. In order to analyze these effects we have obtained, within the Transfer Hamiltonian framework, a general expression for the transition probability for coherent resonant tunneling in terms of the Green's function of the system. 73.40.G
AIP Conference Proceedings, 2005
ABSTRACT We study the current noise spectrum of charge qubits under transport conditions (double ... more ABSTRACT We study the current noise spectrum of charge qubits under transport conditions (double quantum dots and Cooper pair boxes) in a dissipative bosonic environment. We combine master equations with correlation functions in Laplace‐space to derive a noise formula for both weak and strong coupling to the bath. © 2005 American Institute of Physics
Europhysics Letters (epl), 1997
We develope a model to describe the transmission coefficient and tunneling current in the presenc... more We develope a model to describe the transmission coefficient and tunneling current in the presence of photon-electron coupling in a resonant diode. Our model takes into account multiphoton processes as well as the transitions between electronic states with different wave numbers. This is crutial to explain the experimental features observed in the tunneling current through a double barrier which cannot be reproduced with more simplified established models. According to our results, what experiments show in the current density are quantum photon-assisted features coming from multiphoton transitions which are not related with sample heating.
Physical Review B, 1996
We have analyzed the tunneling transmission probability and electronic current density through re... more We have analyzed the tunneling transmission probability and electronic current density through resonant heterostructures in the presence of an external electromagnetic field. In this work, we compare two different models for a double barrier : In the first case the effect of the external field is taken into account by spatially dependent AC voltages and in the second one the electromagnetic field is described in terms of a photon field that irradiates homogeneously the whole sample. While in the first description the tunneling takes place mainly through photo sidebands in the case of homogeneous illumination the main effective tunneling channels correspond to the coupling between different electronic states due to photon absorption and emission. The difference of tunneling mechanisms between these configurations is strongly reflected in the transmission and current density which present very different features in both cases. In order to analyze these effects we have obtained, within the Transfer Hamiltonian framework, a general expression for the transition probability for coherent resonant tunneling in terms of the Green's function of the system. 73.40.G