Robust optical polarization of nuclear spin baths using Hamiltonian engineering of nitrogen-vacancy center quantum dynamics

Schwartz, Ilai; Scheuer, Jochen; Tratzmiller, Benedikt; Müller, S.; Chen, Qiong; Dhand, Ish; Wang, Zhenyu; Müller, Christoph; Naydenov, Boris; Jelezko, Fedor; Plenio, Martin B.

doi:10.1126/sciadv.aat8978

Cited by 121 publications

(132 citation statements)

References 57 publications

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“…In (c) we look at the electron spin state coherence evolution which we simulate with the gate structure in (d), this exhibits a steady and then proceedingly rapid decline, from time 0 to 1 µs, then 1 to 3 µs respectively; it subsequently increases to then stabilize at the 4 to 5 µs interval. The relaxation observed from our virtual system's electron spin resembles relaxation shown in physical NV center experiments 35,44,45 . In physical experiments this is often a result of perturbation by the 13 C nuclear spins around it which decoheres the spin center, but as the pulse sequence comes into effect the system transitions into a steady state.…”

Section: As Shown Insupporting

confidence: 72%

Experimental simulation of hybrid quantum systems and entanglement on a quantum computer

Mazhandu

Mathieson

Coleman

et al. 2019

Applied Physics Letters

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We propose the utilization of the IBM Quantum Experience quantum computing system to simulate different scenarios involving common hybrid quantum system components, the Nitrogen Vacancy Centre (NV centre) and the Flux Qubit. We perform a series of the simulation experiments and demonstrate properties of a virtual hybrid system, including its spin relaxation rate and state coherence. In correspondence with experimental investigations we look at the scalability of such systems and show that increasing the number of coupled NV centres decreases the coherence time. We also establish the main error rate as a function of the number of control pulses in evaluating the fidelity of the four qubit virtual circuit with the simulator. Our results show that the virtual system can attain decoherence and fidelity values comparable to what has been reported for experimental investigations of similar physical hybrid systems, observing a coherence time at 0.35 s for a single NV centre qubit and fidelity in the range of 0.82. The work thus establishes an effective simulation test protocol for different technologies to test and analyze them before experimental investigations or as a supplementary measure.Quantum computers have the potential to solve problems that scale up at polynomial time and are thus predicted to outperform classical computers in a wide range of tasks including machine learning 1 , complex simulations 2-14 and optimization problems 15 . However, to establish true quantum supremacy, there is a need to build and demonstrate universal fault tolerant and scalable computing systems that can extend beyond the capabilities of classical computational systems 16 . To accomplish this several different types of systems and architectures have been proposed and continue to be studied. More recently this has included the demonstration of hybrid systems which combine different complementary quantum device elements, often coupling a combination of a superconducting, atomic and or spin systems into a single circuit 17,18 . NV centres have been studied extensively for this purpose, this is because the spin states associated with the NV centre present a well-studied energy level splitting which can be readily accessed and addressed through both electrical and optical measurement techniques and are thus able to couple relatively easily to circuitry and other device components. It has already been shown that coupled NV centres and flux qubits 19,20 are ideal complimentary elements for such hybrid systems. As both these device elements rely on spin they can easily be coupled, and experimental investigations have demonstrated quantum information transfer between flux qubit and NV centre ensembles 19 . Additionally, NV centres present ideal quantum logic elements and have shown to be useful for a range of operations including as quantum registers and as quantum gates 21,22 . Due to their possibility of realizing fault tolerant logic operations holonomic quantum gates have been widely studied in various systems 21-27 but most notably wit...

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Section: As Shown Insupporting

confidence: 72%

Experimental simulation of hybrid quantum systems and entanglement on a quantum computer

Mazhandu

Mathieson

Coleman

et al. 2019

Applied Physics Letters

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“…An immediate extension of this work will be to perform spin locking in the spectral window of nuclear-spin resonances, i.e. the Hartmann-Hahn regime, to sculpt collective nuclear-spin states [25,26], and also to tailor the electron-nuclear interaction [27][28][29] to realise an ancilla qubit or a local quantum register based on the collective states of the nuclear ensemble [30].…”

Section: Discussionmentioning

confidence: 99%

Optical spin locking of a solid-state qubit

et al. 2019

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Quantum control of solid-state spin qubits typically involves pulses in the microwave domain, drawing from the well-developed toolbox of magnetic resonance spectroscopy. Driving a solid-state spin by optical means offers a high-speed alternative, which in the presence of limited spin coherence makes it the preferred approach for high-fidelity quantum control. Bringing the full versatility of magnetic spin resonance to the optical domain requires full phase and amplitude control of the optical fields. Here, we imprint a programmable microwave sequence onto a laser field and perform electron spin resonance in a semiconductor quantum dot via a two-photon Raman process. We show that this approach yields full SU(2) spin control with over 98% π-rotation fidelity. We then demonstrate its versatility by implementing a particular multi-axis control sequence, known as spin locking. Combined with electron-nuclear Hartmann-Hahn resonances which we also report in this work, this sequence will enable efficient coherent transfer of a quantum state from the electron spin to the mesoscopic nuclear ensemble.

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“…An alternative option is to initialise the quantum systems in the bath in a well-defined state. For nuclear spins, this is typically done by dynamically transferring polarisation from the easily manipulated electron spin to the nuclear environment [27][28][29][30][31]. The standard dynamic nuclear polarisation (DNP) techniques, however, suffer from a number of drawbacks.…”

Section: Introductionmentioning

confidence: 99%

“…Furthermore, some DNP processes require matching the electron and nuclear transition frequencies, which is not a trivial task in the presence of spectral fluctuations. Optical DNP partially mitigates these issues by optically pumping the electrons (albeit still requiring energy matching for polarisation transfer) [30][31][32]. However, this technique is limited by the short photo-excited triplet state lifetime, requiring fast polarisation transfer or weakly coupled nuclear spins [32].…”

Section: Introductionmentioning

confidence: 99%

Extending qubit coherence by adaptive quantum environment learning

2020

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Decoherence, resulting from unwanted interaction between a qubit and its environment, poses a serious challenge towards the development of quantum technologies. Recently, researchers have started analysing how real-time Hamiltonian learning approaches, based on estimating the qubit state faster than the environmental fluctuations, can be used to counteract decoherence. In this work, we investigate how the back-action of the quantum measurements used in the learning process can be harnessed to extend qubit coherence. We propose an adaptive protocol that, by learning the qubit environment, narrows down the distribution of possible environment states. While the outcomes of quantum measurements are random, we show that real-time adaptation of measurement settings (based on previous outcomes) allows a deterministic decrease of the width of the bath distribution, and hence an increase of the qubit coherence. We numerically simulate the performance of the protocol for the electronic spin of a nitrogen-vacancy centre in diamond subject to a dilute bath of 13 C nuclear spin, finding a considerable improvement over the performance of non-adaptive strategies.

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Robust optical polarization of nuclear spin baths using Hamiltonian engineering of nitrogen-vacancy center quantum dynamics

Abstract: A robust and fast principle of optical hyperpolarization is proposed and demonstrated by using NV centers experimentally.

Cited by 121 publications

References 57 publications

Experimental simulation of hybrid quantum systems and entanglement on a quantum computer

Experimental simulation of hybrid quantum systems and entanglement on a quantum computer

Optical spin locking of a solid-state qubit

Extending qubit coherence by adaptive quantum environment learning

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