Analytical model of non-Markovian decoherence in donor-based charge quantum bits

Lastra, F.; Reyes, Sebastian; Wallentowitz, S.

doi:10.1088/0953-4075/44/1/015504

Cited by 6 publications

(14 citation statements)

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“…For long times again a stationaryσ x pointer-state basis is reached asymptotically. The appearance of one or more metastable regimes is due to the non-Markovian nature of the evolution of the system [17][18][19]. Indeed, we have checked that increasing the separation between the qubits, the quantum correlations decay monotonically before reaching a stationary (non zero) value.…”

Section: (T)mentioning

confidence: 99%

Emergence of a metastable pointer-state basis in non-Markovian quantum dynamics

et al. 2014

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We investigate the dynamics of classical and quantum correlations between two qubits. Each qubit is implemented by a pair of phosphorous impurities embedded in a silicon substrate. The main decoherence mechanism affecting these types of qubits is provided by the coupling of the phosphorous impurities to the acoustical vibrations of the silicon lattice. We find that depending on the temperature of the substrate and the initial state, three different dynamics can be found. These are characterized by the number of abrupt changes in both classical and quantum correlations. We also show that the correlations do not disappear. Moreover, before the classical correlations reach a constant value, they may experience successive abrupt changes associated with the apparition of metastable pointer states basis. Then, a constant value for the classical correlations is reached when the preferred basis is established.PACS numbers: 03.65. Yz, 03.65.Ud,03.67Lx Recently the study of classical and quantum correlations has become a central subject of investigation. The study of quantum correlations between quantum systems is a problem as old as the quantum theory. For many years, it was widely believed that quantum entanglement would be the only relevant type of correlation for quantum information protocols. However, it has been proved that efficient quantum protocols can be performed in the absence of entanglement [1]. A bipartite quantum system A-B can feature both quantum and classical correlations between its constituent parts A and B, respectively. All these correlations can be characterized by the quantum mutual information [2, 3]where where C(ρ AB ) are the classical correlations [2], [6] defined by the following maximization procedure: A complete set of projector operators {Π k } must be constructed for the subsystem B. Then the quantity C(ρ AB ) = max

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Section: (T)mentioning

confidence: 99%

Emergence of a metastable pointer-state basis in non-Markovian quantum dynamics

et al. 2014

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“…Multi-channel reservoir coupling occurs when a canonical transformation of reservoir modes cannot reduce the number of reservoir operators appearing in the interaction Hamiltonian to one. Apart from fundamental interest in solving the most general type of reservoir coupling, open quantum systems which can exhibit multi-channel reservoir coupling are now under both theoretical and experimental investigation [22]. Additionally, understanding the effect that multi-channel coupling has on decoherence will likely be important for developing practical quantum information systems.…”

Section: Resultsmentioning

confidence: 99%

“…Apart from the fundamental interest in solving open quantum systems with general multi-channel coupling, there is one system currently under both theoretical and experimental investigation which can exhibit multi-channel reservoir coupling. Donor-based charge quantum bits in a semiconductor host have single-channel reservoir coupling only if the Bohr radii of the s-wave orbitals are exactly equal for all donors [22]. Donor-based charge quantum bits are of particular interest due to their potential use within a scalable architecture for a quantum computer.…”

Section: Introductionmentioning

confidence: 99%

Solving non-Markovian open quantum systems with multi-channel reservoir coupling

Broadbent

Jing

et al. 2012

Annals of Physics

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We extend the non-Markovian quantum state diffusion (QSD) equation to open quantum systems which exhibit multichannel coupling to a harmonic oscillator reservoir. Open quantum systems which have multi-channel reservoir coupling are those in which canonical transformation of reservoir modes cannot reduce the number of reservoir operators appearing in the interaction Hamiltonian to one. We show that the non-Markovian QSD equation for multi-channel reservoir coupling can, in some cases, lead to an exact master equation which we derive. We then derive the exact master equation for the three-level system in a vee-type configuration which has multi-channel reservoir coupling and give the analytical solution. Finally, we examine the evolution of the three-level vee-type system with generalized Ornstein-Uhlenbeck reservoir correlations numerically.

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“…Even, having just one charged impurity could induce qubit decoherence if this impurity is dynamic and has a fluctuation time scale comparable to gate operation time scales [42]. Decoherence is a phenomenon that plays a central role in quantum information and its technological applications [53,54,55,56,57,58,59,60,61,62]. The short transition time in optically driven processes reduces the effect of decoherence sources, such as hyperfine or phonon interactions.…”

Section: Introductionmentioning

confidence: 99%

Optimal control of a charge qubit in a double quantum dot with a Coulomb impurity

Coden

Romero

Ferrón

et al. 2017

Physica E: Low-dimensional Systems and Nanostructures

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Abstract. We study the efficiency of modulated laser pulses to produce efficient and fast charge localization transitions in a two-electron double quantum dot. We use a configuration interaction method to calculate the electronic structure of a quantum dot model within the effective mass approximation. The interaction with the electric field of the laser is considered within the dipole approximation and optimal control theory is applied to design high-fidelity ultrafast pulses in pristine samples. We assessed the influence of the presence of Coulomb charged impurities on the efficiency and speed of the pulses. A protocol based on a two-step optimization is proposed for preserving both advantages of the original pulse. The processes affecting the charge localization is explained from the dipole transitions of the lowest lying two-electron states, as described by a discrete model with an effective electron-electron interaction.

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Analytical model of non-Markovian decoherence in donor-based charge quantum bits

Cited by 6 publications

References 50 publications

Emergence of a metastable pointer-state basis in non-Markovian quantum dynamics

Emergence of a metastable pointer-state basis in non-Markovian quantum dynamics

Solving non-Markovian open quantum systems with multi-channel reservoir coupling

Optimal control of a charge qubit in a double quantum dot with a Coulomb impurity

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