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Counter-diabatic driving for fast spin control in a two-electron double quantum dot.

Ban Y, Chen X - Sci Rep (2014)

Bottom Line: The techniques of shortcuts to adiabaticity have been proposed to accelerate the "slow" adiabatic processes in various quantum systems with the applications in quantum information processing.In addition, the relation between energy and time is quantified to show the lower bound for the operation time when the maximum amplitude of electric fields is given.Finally, the fidelity is discussed with respect to noise and systematic errors, which demonstrates that the decoherence effect induced by stochastic environment can be avoided in speeded-up adiabatic control.

View Article: PubMed Central - PubMed

Affiliation: Department of Electronic Information Materials, Shanghai University, 200444 Shanghai, People's Republic of China.

ABSTRACT
The techniques of shortcuts to adiabaticity have been proposed to accelerate the "slow" adiabatic processes in various quantum systems with the applications in quantum information processing. In this paper, we study the counter-diabatic driving for fast adiabatic spin manipulation in a two-electron double quantum dot by designing time-dependent electric fields in the presence of spin-orbit coupling. To simplify implementation and find an alternative shortcut, we further transform the Hamiltonian in term of Lie algebra, which allows one to use a single Cartesian component of electric fields. In addition, the relation between energy and time is quantified to show the lower bound for the operation time when the maximum amplitude of electric fields is given. Finally, the fidelity is discussed with respect to noise and systematic errors, which demonstrates that the decoherence effect induced by stochastic environment can be avoided in speeded-up adiabatic control.

No MeSH data available.


Schematic diagram of a two-electron double quantum dot in the presence of external electric fields and spin-orbit coupling, where the singlet state and the lowest one of triplet states are considered as effective two-level system, when  with Zeeman term Δ = gμBB.
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f1: Schematic diagram of a two-electron double quantum dot in the presence of external electric fields and spin-orbit coupling, where the singlet state and the lowest one of triplet states are considered as effective two-level system, when with Zeeman term Δ = gμBB.

Mentions: Two electrons are confined in a double QD, described as a quartic potential in Fig. 1, where they are isolated by Coulomb blockade9. In the presence of the applied magnetic fields, the lowest four eigenstates of the system can be expressed by singlet and triplet for S = 0 and S = 1 in the basis of /S, Sz〉. This report presents a method to achieve fast adiabatic transition between the triplet and the singlet. We design the electric fields in x − y plane to manipulate spin states with static magnetic fields along z direction in each dot, considering structure-related Rashba (α) and bulk-originated Dresselhaus (β) for [110] growth axis. If the energy difference between the singlet and the lowest one of the triplet is much less than the gap between the singlet and the triplet, we focus on the state transition between these lowest two, as shown in Fig. 1, where Landé factor g < 0 like in GaAs and InAs QDs.


Counter-diabatic driving for fast spin control in a two-electron double quantum dot.

Ban Y, Chen X - Sci Rep (2014)

Schematic diagram of a two-electron double quantum dot in the presence of external electric fields and spin-orbit coupling, where the singlet state and the lowest one of triplet states are considered as effective two-level system, when  with Zeeman term Δ = gμBB.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4150114&req=5

f1: Schematic diagram of a two-electron double quantum dot in the presence of external electric fields and spin-orbit coupling, where the singlet state and the lowest one of triplet states are considered as effective two-level system, when with Zeeman term Δ = gμBB.
Mentions: Two electrons are confined in a double QD, described as a quartic potential in Fig. 1, where they are isolated by Coulomb blockade9. In the presence of the applied magnetic fields, the lowest four eigenstates of the system can be expressed by singlet and triplet for S = 0 and S = 1 in the basis of /S, Sz〉. This report presents a method to achieve fast adiabatic transition between the triplet and the singlet. We design the electric fields in x − y plane to manipulate spin states with static magnetic fields along z direction in each dot, considering structure-related Rashba (α) and bulk-originated Dresselhaus (β) for [110] growth axis. If the energy difference between the singlet and the lowest one of the triplet is much less than the gap between the singlet and the triplet, we focus on the state transition between these lowest two, as shown in Fig. 1, where Landé factor g < 0 like in GaAs and InAs QDs.

Bottom Line: The techniques of shortcuts to adiabaticity have been proposed to accelerate the "slow" adiabatic processes in various quantum systems with the applications in quantum information processing.In addition, the relation between energy and time is quantified to show the lower bound for the operation time when the maximum amplitude of electric fields is given.Finally, the fidelity is discussed with respect to noise and systematic errors, which demonstrates that the decoherence effect induced by stochastic environment can be avoided in speeded-up adiabatic control.

View Article: PubMed Central - PubMed

Affiliation: Department of Electronic Information Materials, Shanghai University, 200444 Shanghai, People's Republic of China.

ABSTRACT
The techniques of shortcuts to adiabaticity have been proposed to accelerate the "slow" adiabatic processes in various quantum systems with the applications in quantum information processing. In this paper, we study the counter-diabatic driving for fast adiabatic spin manipulation in a two-electron double quantum dot by designing time-dependent electric fields in the presence of spin-orbit coupling. To simplify implementation and find an alternative shortcut, we further transform the Hamiltonian in term of Lie algebra, which allows one to use a single Cartesian component of electric fields. In addition, the relation between energy and time is quantified to show the lower bound for the operation time when the maximum amplitude of electric fields is given. Finally, the fidelity is discussed with respect to noise and systematic errors, which demonstrates that the decoherence effect induced by stochastic environment can be avoided in speeded-up adiabatic control.

No MeSH data available.