Nonadiabatic relaxation control of qubits strongly coupled to continuum edge
- Chemical Physics Department, Weizmann Institute of Science, Rehovot 76100 (Israel)
We propose a method for controlling the decay and decoherence of a driven qubit that is strongly coupled to a reservoir, when the qubit resonance frequency is close to a continuum edge of the reservoir spectrum. This strong-coupling regime is outside the scope of existing methods of decay or decoherence control. We demonstrate that an appropriate sequence of nearly abrupt changes of the resonance frequency can protect the qubit state from decay and decoherence more effectively than the intuitively obvious alternative, which is to fix the resonance well within a forbidden band gap of the reservoir spectrum, as far as possible from the continuum edge. The 'counterintuitive' nonadiabatic method outlined here can outperform its adiabatic counterparts in maintaining a high fidelity of quantum logic operations. The remarkable effectiveness of the proposed method, which requires much lower rates of frequency changes than previously proposed control methods, is due to the ability of appropriately alternating detunings from the continuum edge to augment the interference of the emitted and backscattered quanta, thereby helping to stabilize the qubit state against decay. Applications to the control of decay and decoherence near the edge of radiative, vibrational, and photoionization continua are discussed.
- OSTI ID:
- 20650366
- Journal Information:
- Physical Review. A, Vol. 71, Issue 3; Other Information: DOI: 10.1103/PhysRevA.71.032328; (c) 2005 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1050-2947
- Country of Publication:
- United States
- Language:
- English
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