11 research outputs found
Full protection of superconducting qubit systems from coupling errors
Solid state qubits realized in superconducting circuits are potentially scalable. However, strong decoherence
may be transferred to the qubits by various elements of the circuits that couple individual qubits, particularly
when coupling is implemented over long distances. We propose here an encoding that provides full protection
against errors originating from these coupling elements, for a chain of superconducting qubits with a nearest
neighbor anisotropic XY-interaction. The encoding is also seen to provide partial protection against errors
deriving from general electronic noise
Robust stationary entanglement of two coupled qubits in independent environments
The dissipative dynamics of two interacting qubits coupled to independent
reservoirs at nonzero temperatures is investigated, paying special attention to
the entanglement evolution. The counter-rotating terms in the qubit-qubit
interaction give rise to stationary entanglement, traceable back to the ground
state structure. The robustness of this entanglement against thermal noise is
thoroughly analyzed, establishing that it can be detected at reasonable
experimental temperatures. Some effects linked to a possible reservoir
asymmetry are brought to light.Comment: 8 pages, 6 figures; version accepted for publication on Eur. Phys. J.
Quantum information processing with superconducting qubits in a microwave field
We investigate the quantum dynamics of a Cooper-pair box with a
superconducting loop in the presence of a nonclassical microwave field. We
demonstrate the existence of Rabi oscillations for both single- and
multi-photon processes and, moreover, we propose a new quantum computing scheme
(including one-bit and conditional two-bit gates) based on Josephson qubits
coupled through microwaves.Comment: 7 pages, 1 figur
Quantitative Treatment of Decoherence
We outline different approaches to define and quantify decoherence. We argue
that a measure based on a properly defined norm of deviation of the density
matrix is appropriate for quantifying decoherence in quantum registers. For a
semiconductor double quantum dot qubit, evaluation of this measure is reviewed.
For a general class of decoherence processes, including those occurring in
semiconductor qubits, we argue that this measure is additive: It scales
linearly with the number of qubits.Comment: Revised version, 26 pages, in LaTeX, 3 EPS figure
Full protection of superconducting qubit systems from coupling errors
Solid state qubits realized in superconducting circuits are potentially scalable. However, strong decoherence
may be transferred to the qubits by various elements of the circuits that couple individual qubits, particularly
when coupling is implemented over long distances. We propose here an encoding that provides full protection
against errors originating from these coupling elements, for a chain of superconducting qubits with a nearest
neighbor anisotropic XY-interaction. The encoding is also seen to provide partial protection against errors
deriving from general electronic noise
Full protection of superconducting qubit systems from coupling errors
Solid state qubits realized in superconducting circuits are potentially scalable. However, strong decoherence
may be transferred to the qubits by various elements of the circuits that couple individual qubits, particularly
when coupling is implemented over long distances. We propose here an encoding that provides full protection
against errors originating from these coupling elements, for a chain of superconducting qubits with a nearest
neighbor anisotropic XY-interaction. The encoding is also seen to provide partial protection against errors
deriving from general electronic noise
Full protection of superconducting qubit systems from coupling errors
Solid state qubits realized in superconducting circuits are potentially scalable. However, strong decoherence
may be transferred to the qubits by various elements of the circuits that couple individual qubits, particularly
when coupling is implemented over long distances. We propose here an encoding that provides full protection
against errors originating from these coupling elements, for a chain of superconducting qubits with a nearest
neighbor anisotropic XY-interaction. The encoding is also seen to provide partial protection against errors
deriving from general electronic noise
Full protection of superconducting qubit systems from coupling errors
Solid state qubits realized in superconducting circuits are potentially scalable. However, strong decoherence
may be transferred to the qubits by various elements of the circuits that couple individual qubits, particularly
when coupling is implemented over long distances. We propose here an encoding that provides full protection
against errors originating from these coupling elements, for a chain of superconducting qubits with a nearest
neighbor anisotropic XY-interaction. The encoding is also seen to provide partial protection against errors
deriving from general electronic noise