Abstract
We study the quantum fluctuations of the two quadratures of the emitted electromagnetic radiation generated by a quantum Hall device in a quantum point contact geometry. In particular, we focus our attention on the role played by the unavoidable electron–electron interactions between the two edge channels at filling factor two. We investigate quantum features of the emitted microwave radiation, such as squeezing, by studying the current fluctuations at finite frequency, accessible through a two-filters set-up placed just after the quantum point contact. We compare two different drives, respectively a cosine and a train of Lorentzian pulses, used for the injection of the excitations into the system. In both cases quantum features are reduced due to the interactions, however the Lorentzian drive is still characterized by a robust squeezing effect which can have important application on quantum information.
Highlights
During the last decades, significant theoretical and experimental efforts have been directed towards the control of individual electronic degrees of freedom in mesoscopic devices
We study the quantum fluctuations of the two quadratures of the emitted electromagnetic radiation generated by a quantum Hall device in a quantum point contact geometry
We theoretically investigate the dynamical response of the outgoing current fluctuations, which are associated to the photo-assisted finite frequency noise, in the presence of Coulomb interactions
Summary
Significant theoretical and experimental efforts have been directed towards the control of individual electronic degrees of freedom in mesoscopic devices. Despite the photo-assisted shot noise [37] and the current correlations [38] in the strongly interacting fractional QH regime have been recently experimentally investigated, a detailed analysis of both these effects, in presence of two interacting edge channels, is still lacking but it is necessary because the dynamics of excitations is strongly affected by such phenomena which cannot be avoided in realistic experimental conditions For this reason, a proper theoretical framework in the interacting regime is needed in order to pave the way towards new experiments devoted to the improvement of the quantum behaviour of the associated emitted electromagnetic field. We want to consider the effects a time-dependent periodic voltage Vin(t) applied to the inner channel just before the interacting region (see Figure 1) This can be done through the conventional minimal coupling Hamiltonian density. We will investigate the current which is subjected to fluctuations (noise) and we will focus on the zero temperature limit
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