Scattering phases in quantum dots: an analysis based on lattice models

We study the phase of the transmission amplitude through a disordered quantum dot in the Coulomb blockade regime. We calculate the phase dependence on gate voltage for a disorder configuration. We show that over a ``period'', consisting of a resonance and a transmission valley, the total phase change is 0 (mod $2\pi$). Deviations from this sum rule are small in the parameter (level spacing/charging energy). The disorder-averaged phase-phase correlation function is found showi...

Recently, A. Jerez, P. Vitushinsky and M. Lavagna [Phys. Rev. Lett. 95, 127203 (2005)] claimed that the transmission phase through a quantum fot, as measured via the Aharonov-Bohm interferometer, differs from the phase which determines the corresponding conductance. Here we show that this claim is wrong for the single level Anderson model, which is usually used to describe the quantum dot. So far, there exists no derivation of this claim from any explicit theoretical model.

We present experimental results and a model to solve the problem of "in-phase Coulomb peaks" observed in transport through a quantum dot. In a marginal region between Coulomb-blockade and open-dot, we have observed Fano-type interference through two energy levels inside the dot, which manifest themselves in two overlapped Coulomb-diamond-like structures in the excitation spectrum. One of the two levels is strongly coupled to the leads and the phase of traversing electrons is ...

The influence of electron-phonon interaction on the transmission phase shift of an electron passing through a quantum dot is investigated by using the scattering theory. The transmission phase versus the intra-dot level shows a serial of phonon-induced dips. These dips are highly sensitive to electron-phonon interaction strength $\lambda$, and they are much more pronounced than phonon-assisted sub-peaks appeared in the conductance. Phonon-induce dephasing is also studied, and...

We address the problem of transmission of electrons between two noninteracting leads through a region where they interact (quantum dot). We use a model of spinless electrons hopping on a one-dimensional lattice and with an interaction on a single bond. We show that all the two-particle scattering states can be found exactly. Comparisons are made with numerical results on the time evolution of a two-particle wave packet and several interesting features are found for scattering...

A small quantum dot coupled to two external leads is considered. Different signs of the dot-leads coupling matrix elements give rise to qualitatively different behavior of physical observables such as the conductance, the phase of the transmission amplitude and the differential capacitance of the dot. For certain relative signs the conductance may vanish at values of the gate potential, where the spectral density is maximal. Zeroes of the conductance are robust against increa...

For a variety of quantum dots, the widths of different single-particle levels may naturally differ by orders of magnitude. In particular, the width of one strongly coupled level may be larger than the spacing between other, very narrow, levels. We found that in this case many consecutive Coulomb blockade peaks are due to occupation of the same broad level. Between the peaks the electron jumps from this level to one of the narrow levels and the transmission through the dot at ...

The transmission probability and phase through a few-electron quantum dot are studied within a resonance theory for the strong coupling regime to the conducting leads. We find that the interaction between overlapping resonances leads to their separation in the complex energy plane and to the decoherent dephasing of the resonant modes. The appearance of the Fano effect is conditioned not only by the induced dephasing generally associated with a phase lapse, but also by a favor...

Coherent scattering of light by a single quantum emitter is a fundamental process at the heart of many proposed quantum technologies. Unlike atomic systems, solid-state emitters couple to their host lattice by phonons. Using a quantum dot in an optical nanocavity, we resolve these interactions in both time and frequency domains, going beyond the atomic picture to develop a comprehensive model of light scattering from solid-state emitters. We find that even in the presence of ...

We present theoretical results concerning inelastic light (Raman) scattering from semiconductor quantum dots. The characteristics of each dot state (whether it is a collective or single-particle excitation, its multipolarity, and its spin) are determined independently of the Raman spectrum, in such a way that common beliefs used for level assignments in experimental spectra can be tested. We explore the usefulness of below band gap excitation and an external magnetic field to...