Spin–spin interactions in defects in solids from mixed all-electron and pseudopotential first-principles calculations

Ghosh, Krishnendu; Ma, He; Onizhuk, Mykyta; Gavini, Vikram; Galli, Giulia

doi:10.1038/s41524-021-00590-w

Cited by 18 publications

(11 citation statements)

References 67 publications

(87 reference statements)

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“…1 MHz [41] (about 1 MHz is also the electron linewidth for the neutral divacancy in SiC [28]). For HF strengths > 2π • 6 kHz, the nuclei are within a distance of R < 15 Å from the vacancy site, while strengths on the order of 2π • 1 kHz correspond to a range of within R ∼ 25 Å [42].…”

Section: Synchronous Controlled Gates On Multiple Nuclei a Maximizati...mentioning

confidence: 99%

Precise control of entanglement in multinuclear spin registers coupled to defects

Takou¹,

Barnes²,

Economou³

2022

Preprint

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Quantum networks play an indispensable role in quantum information tasks such as secure communications, enhanced quantum sensing, and distributed computing. Among the most mature and promising platforms for quantum networking are color centers in solids. One of the challenges in using these systems for networking applications is to controllably created and manipulate entanglement between the electron and the nuclear spin register. Here, we develop a general formalism to quantify and control the generation of entanglement in an arbitrarily large nuclear spin register coupled to a defect electronic spin. We provide a reliable measure of nuclear spin selectivity, taking into account the presence of unwanted nuclei. We show how to realize direct multipartite gates through the use of dynamical decoupling sequences, reducing drastically the total gate time compared to protocols based on sequential entanglement with individual nuclear spins. We quantify the performance of such gate operations in the presence of unwanted residual entanglement links, capturing the dynamics of the entire nuclear spin register.

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Section: Synchronous Controlled Gates On Multiple Nuclei a Maximizati...mentioning

confidence: 99%

Precise control of entanglement in multinuclear spin registers coupled to defects

Takou¹,

Barnes²,

Economou³

2022

Preprint

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“…In particular, FE basis provides systematic convergence for any materials system [22], can accommodate periodic, non-periodic and semi-periodic boundary conditions, and can offer excellent parallel scalability owing to the locality of the FE basis functions [28]. Furthermore, the FE basis sets are amenable to adaptive spatial resolution, not only allowing the possibility of large-scale all-electron calculations [26; 35] by combining with enrichment functions, but also mixed all-electron and pseudopotential calculations [36].…”

Section: Introductionmentioning

confidence: 99%

DFT-FE 1.0: A massively parallel hybrid CPU-GPU density functional theory code using finite-element discretization

Das,

Motamarri,

Subramanian

et al. 2022

Preprint

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We present DFT-FE 1.0, building on DFT-FE 0.6 [Comput. Phys. Commun. 246, 106853 (2020)], to conduct fast and accurate large-scale density functional theory (DFT) calculations (reaching ∼ 100, 000 electrons) on both many-core CPU and hybrid CPU-GPU computing architectures. This work involves improvements in the real-space formulation-via an improved treatment of the electrostatic interactions that substantially enhances the computational efficiency-as well highperformance computing aspects, including the GPU acceleration of all the key compute kernels in DFT-FE. We demonstrate the accuracy by comparing the ground-state energies, ionic forces and cell stresses on a wide-range of benchmark systems against those obtained from widely used DFT codes. Further, we demonstrate the numerical efficiency of our implementation, which yields ∼ 20× CPU-GPU speed-up by using GPU acceleration on hybrid CPU-GPU nodes. Notably, owing to the parallel-scaling of the GPU implementation, we obtain wall-times of 80−140 seconds for full groundstate calculations, with stringent accuracy, on benchmark systems containing ∼ 6, 000 − 15, 000 electrons.

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“…[48][49][50][51][52][53][54][55][56][57][58] ), recent developments 59,60 have demonstrated the utility of FE basis for conducting fast and accurate large-scale pseudopotential DFT calculations involving many tens of thousands of electrons [59][60][61][62] . However, for all-electron electronic structure calculations, although prior works 48,49,57,58,[63][64][65][66][67][68][69][70][71][72][73] have demonstrated the systematic convergence of the FE basis, the computational cost remains high, given the large number of FE basis functions that are needed to accurately describe the all-electron wavefunctions. The EFE basis, which enriches the FE basis with compactly supported enrichment functions-such as, for e.g., those constructed from single-atom wavefunctions-can be used to significantly reduce the number of FE basis functions, and consequently improve the computational efficiency of all-electron calculations.…”

Section: Introductionmentioning

confidence: 99%

Ionic forces and stress tensor in all-electron DFT calculations using enriched finite element basis

Rufus,

Gavini

2022

Preprint

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The enriched finite element basis-wherein the finite element basis is enriched with atom-centered numerical functions-has recently been shown to be a computationally efficient basis for systematically convergent all-electron DFT ground-state calculations. In this work, we present the expressions to compute variationally consistent ionic forces and stress tensor for all-electron DFT calculations in the enriched finite element basis. In particular, we extend the formulation of configurational forces in [Motamarri & Gavini (2018)] 1 to the enriched finite element basis and elucidate the additional contributions arising from the enrichment functions. We demonstrate the accuracy of the formulation by comparing the computed forces and stresses for various benchmark systems with those obtained from finite-differencing the ground-state energy. Further, we also benchmark our calculations against Gaussian basis for molecular systems and against the LAPW+lo basis for periodic systems.

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Spin–spin interactions in defects in solids from mixed all-electron and pseudopotential first-principles calculations

Cited by 18 publications

References 67 publications

Precise control of entanglement in multinuclear spin registers coupled to defects

Precise control of entanglement in multinuclear spin registers coupled to defects

DFT-FE 1.0: A massively parallel hybrid CPU-GPU density functional theory code using finite-element discretization

Ionic forces and stress tensor in all-electron DFT calculations using enriched finite element basis

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