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Jan von Delft

The Kondo exciton: non-equilibrium dynamics after a quantum quench in the Anderson impurity model

Location: Dahlem Center room
Time: Tuesday 03.11.2009, 10h s.t.
 

A single confined spin interacting with a solid-state environment has
emerged as one of the fundamental paradigms of mesoscopic physics. In
contrast to standard quantum optical systems, decoherence that stems
from these interactions cannot be treated using the Born-Markov
approximation at low temperatures. Here we study the non-equilibrium
dynamics following a quantum quench of a single-spin in a semiconductor
quantum dot adjacent to a Fermionic reservoir and show how the dynamics
can be revealed in detail in an optical absorption experiment. We show
that the highly asymmetrical optical absorption lineshape of the
resulting Kondo exciton consists of three distinct frequency domains,
corresponding to short, intermediate and long times after the initial
excitation, which are in turn described by the three fixed points of the
single-impurity Anderson Hamiltonian. In particular, the zero
temperature power-law singularity dominating the lineshape is linked to
dynamically generated Kondo correlations in the photo-excited state.

 

 

More information:  P. Brouwer e-mail  


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