Tunable decoherence in the vicinity of a normal metal-superconducting junction
Abstract
The decoherence rate of a quantum dot coupled to a fluctuating environment described by a normal-metal-superconductor junction is considered. The density-density correlator at low frequencies constitutes a kernel which enters the calculation of the phase coherence time. The density fluctuations are connected to the finite-frequency current-current correlations in the point contact via the continuity equation. Below and above the gap, at zero temperature the density correlator contains spatial oscillations at half of the Fermi wavelength on the normal side. As the bias crosses the superconducting gap, the opening of scattering channels enhances the decoherence rate dramatically, suggesting the possibility of tuning the decoherence rate in a controllable manner.
- Publication:
-
Physical Review B
- Pub Date:
- July 2001
- DOI:
- 10.1103/PhysRevB.64.035315
- arXiv:
- arXiv:cond-mat/0011244
- Bibcode:
- 2001PhRvB..64c5315G
- Keywords:
-
- 74.40.+k;
- 72.70.+m;
- 74.50.+r;
- 03.65.Yz;
- Fluctuations;
- Noise processes and phenomena;
- Tunneling phenomena;
- point contacts weak links Josephson effects;
- Decoherence;
- open systems;
- quantum statistical methods;
- Condensed Matter - Mesoscale and Nanoscale Physics;
- Condensed Matter - Superconductivity
- E-Print:
- 8 pages, 3 figures