Quantum impurity approach to a coupled qubit problem
Abstract
We consider a system of two qubits at the ends of a finite length 1D cavity. This problem is mapped onto the doubleKondo model which is also shown to describe the lowenergy physics of a finitelength quantum wire with resonant levels at its ends. At the Toulouse point the groundstate energy and the average populations and correlations of the qubits or resonant levels at zero temperature are computed. These results show that the effective interactions between the qubits or resonant levels can be used to probe their associated Kondo length scale.
 Publication:

EPL (Europhysics Letters)
 Pub Date:
 October 2004
 DOI:
 10.1209/epl/i2004102191
 arXiv:
 arXiv:condmat/0405597
 Bibcode:
 2004EL.....68...37C
 Keywords:

 Condensed Matter  Mesoscopic Systems and Quantum Hall Effect;
 Quantum Physics
 EPrint:
 New version (accepted in Europhysics Letters)