Polarization of a Charge Qubit Strongly Coupled to a Voltage-Driven Quantum Point Contact
Abstract
We study a charge qubit with level splitting ɛ, coupled to a quantum point contact driven by voltage V. In the limit of weak coupling, the qubit polarization shows cusps at ɛ=±eV. We show that, for stronger couplings, prominent peculiarities occur at fractions ɛ=±eV/2. Further increase of the coupling leads to a polarization corresponding to a pseudo Boltzmann distribution with an effective temperature ∼eV.
- Publication:
-
Physical Review Letters
- Pub Date:
- August 2007
- DOI:
- 10.1103/PhysRevLett.99.096802
- arXiv:
- arXiv:cond-mat/0701017
- Bibcode:
- 2007PhRvL..99i6802S
- Keywords:
-
- 73.23.-b;
- 03.67.Lx;
- 73.40.Jn;
- 85.30.Hi;
- Electronic transport in mesoscopic systems;
- Quantum computation;
- Metal-to-metal contacts;
- Surface barrier boundary and point contact devices;
- Condensed Matter - Mesoscale and Nanoscale Physics
- E-Print:
- 7 pages, 6 figures