Limits...
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.


Related in: MedlinePlus

Dependence of  on short time tf (solid blue line), where the dashed straight line shows the asymptotic exponent of tf, i.e. .
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4150114&req=5

f4: Dependence of on short time tf (solid blue line), where the dashed straight line shows the asymptotic exponent of tf, i.e. .

Mentions: Comparisons of and provided by different times suggest that stronger electric fields have to be used for shorter times, though the amplitude of electric fields might be optimized by using superadiabatic iterations32. However, the amplitude of electric fields cannot be arbitrarily large simply because strong fields may destroy the systems. In order to quantify the energy price mentioned above, we demonstrate the relation between the maximal values of electric fields and the operation time tf, see Fig. 4. The maximal amplitude of electric fields, , fulfills the scaling law at very short times, since and go to infinity in the limit of tf → 0. The asymptotic exponent of tf implies that the minimal time should be , which provides the lower bound of operation time when the maximal amplitude of electric fields is given. If the spin system in quantum dot, rather than the atom in harmonic trap, is considered as working medium in the cooling cycles of quantum refrigerator, the minimal time for the (accelerated) adiabatic process, bounded by the energy, could be relevant to the third law of thermodynamics and the unattainability principle3435.


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

Ban Y, Chen X - Sci Rep (2014)

Dependence of  on short time tf (solid blue line), where the dashed straight line shows the asymptotic exponent of tf, i.e. .
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f4: Dependence of on short time tf (solid blue line), where the dashed straight line shows the asymptotic exponent of tf, i.e. .
Mentions: Comparisons of and provided by different times suggest that stronger electric fields have to be used for shorter times, though the amplitude of electric fields might be optimized by using superadiabatic iterations32. However, the amplitude of electric fields cannot be arbitrarily large simply because strong fields may destroy the systems. In order to quantify the energy price mentioned above, we demonstrate the relation between the maximal values of electric fields and the operation time tf, see Fig. 4. The maximal amplitude of electric fields, , fulfills the scaling law at very short times, since and go to infinity in the limit of tf → 0. The asymptotic exponent of tf implies that the minimal time should be , which provides the lower bound of operation time when the maximal amplitude of electric fields is given. If the spin system in quantum dot, rather than the atom in harmonic trap, is considered as working medium in the cooling cycles of quantum refrigerator, the minimal time for the (accelerated) adiabatic process, bounded by the energy, could be relevant to the third law of thermodynamics and the unattainability principle3435.

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.


Related in: MedlinePlus