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Integrated information storage and transfer with a coherent magnetic device.

Jia N, Banchi L, Bayat A, Dong G, Bose S - Sci Rep (2015)

Bottom Line: Quantum systems are inherently dissipation-less, making them excellent candidates even for classical information processing.The proposed mechanism can be realized with different setups.We specifically show that molecular magnets, as the most promising technology, can implement hundreds of operations within their coherence time, while adatoms on surfaces probed by a scanning tunneling microscope is a future possibility.

View Article: PubMed Central - PubMed

Affiliation: State key laboratory of precision spectroscopy, Department of Physics, East China Normal University, Shanghai 200062, China.

ABSTRACT
Quantum systems are inherently dissipation-less, making them excellent candidates even for classical information processing. We propose to use an array of large-spin quantum magnets for realizing a device which has two modes of operation: memory and data-bus. While the weakly interacting low-energy levels are used as memory to store classical information (bits), the high-energy levels strongly interact with neighboring magnets and mediate the spatial movement of information through quantum dynamics. Despite the fact that memory and data-bus require different features, which are usually prerogative of different physical systems--well isolation for the memory cells, and strong interactions for the transmission--our proposal avoids the notorious complexity of hybrid structures. The proposed mechanism can be realized with different setups. We specifically show that molecular magnets, as the most promising technology, can implement hundreds of operations within their coherence time, while adatoms on surfaces probed by a scanning tunneling microscope is a future possibility.

No MeSH data available.


Related in: MedlinePlus

Decoherence in high energy subspace.(a) The bit-tranfer fidelity F(t) in the data-bus subspace with dephasing rate γ = 0.5J when D = −20J and N = 2. The chosen value for γ is extremely pessimistic even for larger chains, and we have chosen this value in order to show the decay in shorter time scales. (b) The maximum fidelity Fmax as a function of γ for two different values of anisotropy E, when D = −20J and N = 2.
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f6: Decoherence in high energy subspace.(a) The bit-tranfer fidelity F(t) in the data-bus subspace with dephasing rate γ = 0.5J when D = −20J and N = 2. The chosen value for γ is extremely pessimistic even for larger chains, and we have chosen this value in order to show the decay in shorter time scales. (b) The maximum fidelity Fmax as a function of γ for two different values of anisotropy E, when D = −20J and N = 2.

Mentions: We first consider the case where the system is prepared in the high-energy subspace for computational tasks and we study the effect of dephasing on the fidelity of state transmission. As an example the two-site system is initialized in the pure state , where , but because of the non-unitary evolution (12) it evolves into a mixed state ρ(t). The resulting fidelity of state swap is therefore . In Fig. 6(a) we plot F(t) as a function of time for a very strong γ = 0.5J. We have chosen a high value of γ to show its effect on the coherent dynamics of our system within shorter time scales. The realistic values are indeed much smaller (γ ≈ 10−3J as discussed in the next section) and allows for very high quality transfer even in long chains. Due to the damping dynamics shown in the plot it is wise to only concentrate on the first peak of the fidelity Fmax. The latter quantity is displayed in Fig. 6(b) as a function of the dephasing rate γ and for different values of E. As it is expected Fmax exponentially decays with the increase of γ. The decay rate only weakly depends on E and slightly become faster for larger E.


Integrated information storage and transfer with a coherent magnetic device.

Jia N, Banchi L, Bayat A, Dong G, Bose S - Sci Rep (2015)

Decoherence in high energy subspace.(a) The bit-tranfer fidelity F(t) in the data-bus subspace with dephasing rate γ = 0.5J when D = −20J and N = 2. The chosen value for γ is extremely pessimistic even for larger chains, and we have chosen this value in order to show the decay in shorter time scales. (b) The maximum fidelity Fmax as a function of γ for two different values of anisotropy E, when D = −20J and N = 2.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4561894&req=5

f6: Decoherence in high energy subspace.(a) The bit-tranfer fidelity F(t) in the data-bus subspace with dephasing rate γ = 0.5J when D = −20J and N = 2. The chosen value for γ is extremely pessimistic even for larger chains, and we have chosen this value in order to show the decay in shorter time scales. (b) The maximum fidelity Fmax as a function of γ for two different values of anisotropy E, when D = −20J and N = 2.
Mentions: We first consider the case where the system is prepared in the high-energy subspace for computational tasks and we study the effect of dephasing on the fidelity of state transmission. As an example the two-site system is initialized in the pure state , where , but because of the non-unitary evolution (12) it evolves into a mixed state ρ(t). The resulting fidelity of state swap is therefore . In Fig. 6(a) we plot F(t) as a function of time for a very strong γ = 0.5J. We have chosen a high value of γ to show its effect on the coherent dynamics of our system within shorter time scales. The realistic values are indeed much smaller (γ ≈ 10−3J as discussed in the next section) and allows for very high quality transfer even in long chains. Due to the damping dynamics shown in the plot it is wise to only concentrate on the first peak of the fidelity Fmax. The latter quantity is displayed in Fig. 6(b) as a function of the dephasing rate γ and for different values of E. As it is expected Fmax exponentially decays with the increase of γ. The decay rate only weakly depends on E and slightly become faster for larger E.

Bottom Line: Quantum systems are inherently dissipation-less, making them excellent candidates even for classical information processing.The proposed mechanism can be realized with different setups.We specifically show that molecular magnets, as the most promising technology, can implement hundreds of operations within their coherence time, while adatoms on surfaces probed by a scanning tunneling microscope is a future possibility.

View Article: PubMed Central - PubMed

Affiliation: State key laboratory of precision spectroscopy, Department of Physics, East China Normal University, Shanghai 200062, China.

ABSTRACT
Quantum systems are inherently dissipation-less, making them excellent candidates even for classical information processing. We propose to use an array of large-spin quantum magnets for realizing a device which has two modes of operation: memory and data-bus. While the weakly interacting low-energy levels are used as memory to store classical information (bits), the high-energy levels strongly interact with neighboring magnets and mediate the spatial movement of information through quantum dynamics. Despite the fact that memory and data-bus require different features, which are usually prerogative of different physical systems--well isolation for the memory cells, and strong interactions for the transmission--our proposal avoids the notorious complexity of hybrid structures. The proposed mechanism can be realized with different setups. We specifically show that molecular magnets, as the most promising technology, can implement hundreds of operations within their coherence time, while adatoms on surfaces probed by a scanning tunneling microscope is a future possibility.

No MeSH data available.


Related in: MedlinePlus