Incomplete pure dephasing of N-qubit entangled W states
arXiv:cond-mat/0703075 · doi:10.1103/PhysRevB.76.045317
Abstract
We consider qubits in a linear arrangement coupled to a bosonic field which acts as a quantum heat bath and causes decoherence. By taking the spatial separation of the qubits explicitly into account, the reduced qubit dynamics acquires an additional non-Markovian element. We investigate the time evolution of an entangled many-qubit W state, which for vanishing qubit separation remains robust under pure dephasing. For finite separation, by contrast, the dynamics is no longer decoherence-free. On the other hand, spatial noise correlations may prevent a complete dephasing. While a standard Bloch-Redfield master equation fails to describe this behavior even qualitatively, we propose instead a widely applicable causal master equation. Here we employ it to identify and characterize decoherence-poor subspaces. Consequences for quantum error correction are discussed.
14 pages, 6 figures, revised version, to appear in Phys. Rev. B
References in corpus (8)
- Scalable multi-particle entanglement of trapped ions
- Entangled three-qubit states without concurrence and three-tangle
- Fault-Tolerant Quantum Computation For Local Non-Markovian Noise
- Decoherence Rate of Semiconductor Charge Qubit Coupled to Acoustic Phonon Reservoir
- Complete disentanglement by partial pure dephasing
- Phonon Decoherence of a Double Quantum Dot Charge Qubit
- Quantum state preparation in circuit QED via Landau-Zener tunneling
- Limitation of entanglement due to spatial qubit separation
Cited by in corpus (6)
- On the conundrum of deriving exact solutions from approximate master equations
- Overcoming non-Markovian dephasing in single photon sources through post-selection
- Electron transport across a quantum wire in the presence of electron leakage to a substrate
- Collective photon emission in solid state environments: Concatenating non-markovian and markovian dynamics
- Nanophotonic Super-dephasing in Collective Atom-Atom Interactions
- Decoherence of encoded quantum registers