Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:2310.04371 · Physical Review A

Rapid transform optimization strategy for decoherence-protected quantum register in diamond

Jiazhao Tian, Haibin Liu, Roberto Sailer, Liantuan Xiao, Fedor Jelezko, Ressa S. Said

Published Feb 21, 2024• 2 citations
arXivHTMLPDF

Abstract

Decoherence-protected spins associated with nitrogen-vacancy color centers in diamond possess remarkably long coherence time, which makes them one of the most promising and robust quantum registers. The current demand is to explore practical rapid control strategies for preparing and manipulating such registers. Our work provides all-microwave control strategies optimized using multiple optimization methods to significantly reduce the processing time by $80%$ with a set of smooth near-zero-end-point control fields that are shown to be experimentally realizable. Furthermore, we optimize and analyze the robustness of these strategies under frequency and amplitude imperfections of the control fields, during which process we use only 16 samples to give a fair estimation of the robustness map with 2500 pixels. Overall, we provide a ready-to-implement recipe to facilitate high-performance information processing via a decoherence-protected quantum register for future quantum technology applications.

DOI
10.1103/physreva.109.022614

Related papers

Robust coherent optimal control of nitrogen-vacancy quantum bits in diamond

Andreas Angerer

During the last ten years, basic quantum operations on a single electronic spins in the nitrogen-vacancy defect center in diamond have been a rich field of study. Quantum operations coherently manipulating the spin of the nitrogen-vacancy center have become promising candidates for easy to manipulate qubits. However in order to implement these qubits in quantum computers robust high-fidelity control is needed. Building on an existing confocal microscopy setup, pulsed and quadrature-amplitude modulated microwave signals were used to realize coherent spin manipulation measurements. Especially designed Smooth Optimal Control pulses (robust against detuning and different control amplitudes) were used to develop measurement schemes resulting in the aforementioned increase of fidelity. The first part of the thesis describes the implementation of these pulses into the existing experimental setup and the calibration work necessary prior to measurements, due to imperfections of devices in the microwave chain. The second part is dedicated to the analysis of the pulses applied to a single spin by comparing the experimental results to theoretical simulations. This was done not only for one resonant spin with accurate control amplitude, but also for a range of different detunings and amplitudes. A more thorough analysis of the pulses was then achieved by using state/process tomography, resulting in a complete description of the process induced by these optimized pulses. Finally, after verifying the effect of the pulses, measurement schemes for sensing alternating magnetic fields were implemented, resulting in measurements with improved sensitivity for magnetic fields.

•Mar 1, 2014•1 citation

Decoherence-protected quantum register of nuclear spins in diamond

F.J. Gonzalez, Raúl Coto

Abstract Solid-state quantum registers are exceptional for storing quantum information at room temperature with long coherence time. Nevertheless, practical applications toward quantum supremacy require even longer coherence time to allow for more complex algorithms. In this work we propose a quantum register that lies in a decoherence-protected subspace to be implemented with nuclear spins nearby a nitrogen-vacancy center in diamond. The quantum information is encoded in two logical states composed of two carbon-13 nuclear spins, while an electron spin is used as ancilla for initialization and control. Moreover, by tuning an off-axis magnetic field we enable non-nuclear-spin-preserving transitions that we use for preparing and manipulating the register through stimulating Raman adiabatic passage. Furthermore, we consider more elaborated sequences to improve simultaneous control over the system yielding decreased gate time.

arXiv:2104.09666•Quantum Science and Technology•Jan 10, 2022•11 citations

Robust Quantum Control for the Manipulation of Solid-State Spins

Yifan Zhang, Hao Wu, Xiaodong Yang +7 more

Robust and high-fidelity control of electron spins in solids is the cornerstone for facilitating applications of solid-state spins in quantum information processing and quantum sensing. However, precise control of spin systems is always challenging due to the presence of various noises originating from the thermal environment and control fields. Here, noise-resilient quantum gates, designed with robust optimal control (ROC) algorithms, are demonstrated experimentally with nitrogen-vacancy centers in diamond to realize tailored robustness against detunings and Rabi errors simultaneously. In the presence of both 10% off-resonance detuning and 10% deviation of a Rabi frequency, we achieve an average single-qubit gate fidelity of up to 99.89%. Our experiments also show that, ROC-based multipulse quantum sensing sequences can suppress spurious responses resulting from finite widths and imperfections of microwave pulses, which provides an efficient strategy for enhancing the performance of existing multipulse quantum sensing sequences.

arXiv:2205.02434•Physical Review Applied•Mar 21, 2023•15 citations

Optimal quantum optical control of spin in diamond

Jiazhao Tian, Tianyi Du, Yu Liu +4 more

The nitrogen-vacancy (NV) center spin represents an appealing candidate for quantum information processing. Besides the widely used microwave control, its coherent manipulation may also be achieved using a laser as mediated by the excited energy levels. Nevertheless, the multiple levels of the excited state of the NV center spin make the coherent transition process become complex and may affect the fidelity of coherent manipulation. Here, we adopt the strategy of optimal quantum control to accelerate coherent-state transfer in the ground-state manifold of the NV center spin using a laser. The results demonstrate improved performance in both the speed and the fidelity of coherent-state transfer which will be useful for optical control of the NV center spin in diamond.

arXiv:2204.13984•Physical Review A•Jul 11, 2019•21 citations

Tailoring of measurement protocols for biomagnetic signals using quantum optimal control on NV centers in diamond

Isabell Jauch, Thomas Strohm, Tino Fuchs +1 more

Nitrogen-vacancy (NV) centers in diamond are a promising platform for ambient, high-spatial resolution magnetometry relevant to biological signals such as cardiac and muscle activity. One of the challenges is the development of pulse sequences tailored to biological signals in the near DC-range. The spatial environment of NV centers within the diamond lattice is highly complex, e.g. due to magnetic field inhomogeneities, limiting the sensors performance. To overcome these experimental constraints, quantum optimal control (QOC) aims at a precise manipulation of the systems dynamics via optimally shaped microwave pulses increasing the overall robustness of spin-based quantum sensors.

Optical and Quantum Sensing and Precision Metrology II•Mar 5, 2026•0 citations

Coherent manipulation of nitrogen-vacancy centers in diamond via frequency multiplication

Pin Yu -, Rujian Zhang, Renfei Zheng +4 more

Nitrogen-vacancy (NV) centers in diamond as ideally individual spin quantum systems can be coherently manipulated by microwave fields. Compared to the traditional method using the IQ (In-phase/Quadrature) mixer with a local oscillator and intermediate-frequency (IF) signals, we report an effective and technically simple method to generate the required microwave field by frequency multiplication and realize coherent manipulation of the NV center’s electron spin. After frequency multiplication, the IF signal can be directly converted to the high-frequency microwave field with adjustable pulse width, frequency, phase, and amplitude. A series of spin dynamics applications such as Rabi oscillation, free induction decay, and spin-locking are executed, which verified its performance and feasibility. Frequency multiplication can overcome the problem of clock synchronization between the local oscillator and IF signal and greatly reduce the complexity of the experimental system. The method can be easily used to realize a more complex quantum control sequence such as dynamic decoupling and extended to a wide range of spin-based quantum information applications in the future.

AIP Advances•Jun 1, 2023•0 citations
Decoherence-protected spins associated with nitrogen-vacancy color centers in diamond possess remarkably long coherence time, which makes them one of the most promising and robust quantum registers. The current demand is to explore practical rapid control strategies for preparing and manipulating such registers. Our work provides all-microwave control strategies optimized using multiple optimization methods to significantly reduce the processing time by 8080%80 with a set of smooth near-zero-end-point control fields that are shown to be experimentally realizable. Furthermore, we optimize and analyze the robustness of these strategies under frequency and amplitude imperfections of the control fields, during which process we use only 16 samples to give a fair estimation of the robustness map with 2500 pixels. Overall, we provide a ready-to-implement recipe to facilitate high-performance information processing via a decoherence-protected quantum register for future quantum technology applications.
During the last ten years, basic quantum operations on a single electronic spins in the nitrogen-vacancy defect center in diamond have been a rich field of study. Quantum operations coherently manipulating the spin of the nitrogen-vacancy center have become promising candidates for easy to manipulate qubits. However in order to implement these qubits in quantum computers robust high-fidelity control is needed. Building on an existing confocal microscopy setup, pulsed and quadrature-amplitude modulated microwave signals were used to realize coherent spin manipulation measurements. Especially designed Smooth Optimal Control pulses (robust against detuning and different control amplitudes) were used to develop measurement schemes resulting in the aforementioned increase of fidelity. The first part of the thesis describes the implementation of these pulses into the existing experimental setup and the calibration work necessary prior to measurements, due to imperfections of devices in the microwave chain. The second part is dedicated to the analysis of the pulses applied to a single spin by comparing the experimental results to theoretical simulations. This was done not only for one resonant spin with accurate control amplitude, but also for a range of different detunings and amplitudes. A more thorough analysis of the pulses was then achieved by using state/process tomography, resulting in a complete description of the process induced by these optimized pulses. Finally, after verifying the effect of the pulses, measurement schemes for sensing alternating magnetic fields were implemented, resulting in measurements with improved sensitivity for magnetic fields.
Abstract Solid-state quantum registers are exceptional for storing quantum information at room temperature with long coherence time. Nevertheless, practical applications toward quantum supremacy require even longer coherence time to allow for more complex algorithms. In this work we propose a quantum register that lies in a decoherence-protected subspace to be implemented with nuclear spins nearby a nitrogen-vacancy center in diamond. The quantum information is encoded in two logical states composed of two carbon-13 nuclear spins, while an electron spin is used as ancilla for initialization and control. Moreover, by tuning an off-axis magnetic field we enable non-nuclear-spin-preserving transitions that we use for preparing and manipulating the register through stimulating Raman adiabatic passage. Furthermore, we consider more elaborated sequences to improve simultaneous control over the system yielding decreased gate time.
Robust and high-fidelity control of electron spins in solids is the cornerstone for facilitating applications of solid-state spins in quantum information processing and quantum sensing. However, precise control of spin systems is always challenging due to the presence of various noises originating from the thermal environment and control fields. Here, noise-resilient quantum gates, designed with robust optimal control (ROC) algorithms, are demonstrated experimentally with nitrogen-vacancy centers in diamond to realize tailored robustness against detunings and Rabi errors simultaneously. In the presence of both 10% off-resonance detuning and 10% deviation of a Rabi frequency, we achieve an average single-qubit gate fidelity of up to 99.89%. Our experiments also show that, ROC-based multipulse quantum sensing sequences can suppress spurious responses resulting from finite widths and imperfections of microwave pulses, which provides an efficient strategy for enhancing the performance of existing multipulse quantum sensing sequences.
The nitrogen-vacancy (NV) center spin represents an appealing candidate for quantum information processing. Besides the widely used microwave control, its coherent manipulation may also be achieved using a laser as mediated by the excited energy levels. Nevertheless, the multiple levels of the excited state of the NV center spin make the coherent transition process become complex and may affect the fidelity of coherent manipulation. Here, we adopt the strategy of optimal quantum control to accelerate coherent-state transfer in the ground-state manifold of the NV center spin using a laser. The results demonstrate improved performance in both the speed and the fidelity of coherent-state transfer which will be useful for optical control of the NV center spin in diamond.
Nitrogen-vacancy (NV) centers in diamond are a promising platform for ambient, high-spatial resolution magnetometry relevant to biological signals such as cardiac and muscle activity. One of the challenges is the development of pulse sequences tailored to biological signals in the near DC-range. The spatial environment of NV centers within the diamond lattice is highly complex, e.g. due to magnetic field inhomogeneities, limiting the sensors performance. To overcome these experimental constraints, quantum optimal control (QOC) aims at a precise manipulation of the systems dynamics via optimally shaped microwave pulses increasing the overall robustness of spin-based quantum sensors.
Nitrogen-vacancy (NV) centers in diamond as ideally individual spin quantum systems can be coherently manipulated by microwave fields. Compared to the traditional method using the IQ (In-phase/Quadrature) mixer with a local oscillator and intermediate-frequency (IF) signals, we report an effective and technically simple method to generate the required microwave field by frequency multiplication and realize coherent manipulation of the NV center’s electron spin. After frequency multiplication, the IF signal can be directly converted to the high-frequency microwave field with adjustable pulse width, frequency, phase, and amplitude. A series of spin dynamics applications such as Rabi oscillation, free induction decay, and spin-locking are executed, which verified its performance and feasibility. Frequency multiplication can overcome the problem of clock synchronization between the local oscillator and IF signal and greatly reduce the complexity of the experimental system. The method can be easily used to realize a more complex quantum control sequence such as dynamic decoupling and extended to a wide range of spin-based quantum information applications in the future.