Article

Many-body dynamics of exciton creation in a quantum dot by optical absorption: a quantum quench towards Kondo correlations.

Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08544, USA.
Physical Review Letters (Impact Factor: 7.73). 03/2011; 106(10):107402. DOI: 10.1103/PhysRevLett.106.107402
Source: PubMed

ABSTRACT We study a quantum quench for a semiconductor quantum dot coupled to a fermionic reservoir, induced by the sudden creation of an exciton via optical absorption. The subsequent emergence of correlations between spin degrees of freedom of dot and reservoir, culminating in the Kondo effect, can be read off from the absorption line shape and understood in terms of the three fixed points of the single-impurity Anderson model. At low temperatures the line shape is dominated by a power-law singularity, with an exponent that depends on gate voltage and, in a universal, asymmetric fashion, on magnetic field, indicative of a tunable Anderson orthogonality catastrophe.

0 Bookmarks
 · 
65 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: We investigate the effect of many-body interactions on the optical absorption spectrum of a charge-tunable quantum dot coupled to a degenerate electron gas. A constructive Fano interference between an indirect path, associated with an intra-dot exciton generation followed by tunneling, and a direct path, associated with the ionization of a valence-band quantum dot electron, ensures the visibility of the ensuing Fermi-edge singularity despite weak absorption strength. We find good agreement between experiment and renormalization group theory, but only when we generalize the Anderson impurity model to include a static hole and a dynamic dot-electron scattering potential. The latter is a consequence of the significant transient probability amplitude for intra-dot excitation and differentiates our work from earlier studies of X-ray absorption by an ensemble of deep-level states.
    04/2013;
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Recent advances in quantum electronics have allowed to engineer hybrid nano-devices comprising on chip a microwave electromagnetic resonator coupled to an artificial atom, a quantum dot. These systems realize novel platforms to explore non-equilibrium quantum impurity physics with light and matter. Coupling the quantum dot system to reservoir leads (source and drain) produces an electronic current as well as dissipation when applying a bias voltage across the system. Focusing on a standard model of biased quantum dot coupled to a photon mode we elucidate the signatures of the electronic correlations in the phase of the transmitted microwave signal. In addition, we illustrate the effect of the electronic degrees of freedom on the photon field, giving rise to non-linearities, damping and dissipation, and discuss how to control these effects by means of gate and bias voltages.
    Physical Review B 10/2013; 89(19). · 3.66 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The gapless edge modes of the quantum spin Hall insulator form a helical liquid in which the direction of motion along the edge is determined by the spin orientation of the electrons. In order to probe the Luttinger liquid physics of these edge states and their interaction with a magnetic (Kondo) impurity, we consider a setup where the helical liquid is tunnel coupled to a semiconductor quantum dot that is excited by optical absorption, thereby inducing an effective quantum quench of the tunneling. At low energy, the absorption spectrum is dominated by a power-law singularity. The corresponding exponent is directly related to the interaction strength (Luttinger parameter) and can be computed exactly using boundary conformal field theory thanks to the unique nature of the quantum spin Hall edge.
    Physical Review Letters 04/2014; 112(14):146804. · 7.73 Impact Factor

Full-text (2 Sources)

Download
60 Downloads
Available from
Jun 3, 2014