Room-temperature control and electrical readout of individual nitrogen-vacancy nuclear spins

AbstractNuclear spins in semiconductors are leading candidates for future quantum technologies, including quantum computation, communication, and sensing. Nuclear spins in diamond are particularly attractive due to their long coherence time. With the nitrogen-vacancy (NV) centre, such nuclear qubits benefit from an auxiliary electronic qubit, which, at cryogenic temperatures, enables probabilistic entanglement mediated optically by photonic links. Here, we demonstrate a concept of a microelectronic quantum device at ambient conditions using diamond as wide bandgap semiconductor. The basic quantum processor unit – a single 14N nuclear spin coupled to the NV electron – is read photoelectrically and thus operates in a manner compatible with nanoscale electronics. The underlying theory provides the key ingredients for photoelectric quantum gate operations and readout of nuclear qubit registers. This demonstration is, therefore, a step towards diamond quantum devices with a readout area limited by inter-electrode distance rather than by the diffraction limit. Such scalability could enable the development of electronic quantum processors based on the dipolar interaction of spin-qubits placed at nanoscopic proximity.

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Beating the standard quantum limit under ambient conditions with solid-state spins

Science Advances ◽

10.1126/sciadv.abg9204 ◽

2021 ◽

Vol 7 (32) ◽

pp. eabg9204

Author(s):

Tianyu Xie ◽

Zhiyuan Zhao ◽

Xi Kong ◽

Wenchao Ma ◽

Mengqi Wang ◽

...

Keyword(s):

Solid State ◽

Nitrogen Vacancy ◽

Quantum Limit ◽

Phase Sensitivity ◽

Ambient Conditions ◽

Nuclear Spins ◽

Standard Quantum ◽

Standard Quantum Limit ◽

Negative State ◽

State Spin

The use of entangled sensors improves the precision limit from the standard quantum limit (SQL) to the Heisenberg limit. Most previous experiments beating the SQL are performed on the sensors that are well isolated under extreme conditions. Here, we demonstrate a sub-SQL interferometer at ambient conditions by using a multispin system, namely, the nitrogen-vacancy (NV) defect in diamond. We achieve two-spin interference with a phase sensitivity of 1.79 ± 0.06 dB beyond the SQL and three-spin interference with a phase sensitivity of 2.77 ± 0.10 dB. Besides, a magnetic sensitivity of 0.87 ± 0.09 dB beyond the SQL is achieved by two-spin interference for detecting a real magnetic field. Particularly, the deterministic and joint initialization of NV negative state, NV electron spin, and two nuclear spins is realized at room temperature. The techniques used here are of fundamental importance for quantum sensing and computing, and naturally applicable to other solid-state spin systems.

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Ultra-sensitive hybrid diamond nanothermometer

National Science Review ◽

10.1093/nsr/nwaa194 ◽

2020 ◽

Author(s):

Chu-Feng Liu ◽

Weng-Hang Leong ◽

Kangwei Xia ◽

Xi Feng ◽

Amit Finkler ◽

...

Keyword(s):

Temperature Sensitivity ◽

Magnetic Nanoparticle ◽

Coherence Time ◽

Nitrogen Vacancy ◽

Field Variation ◽

Ambient Conditions ◽

Nanoscale Systems ◽

Copper Nickel Alloy ◽

Improved Design ◽

Spin Resonances

Abstract Nitrogen-vacancy (NV) centers in diamond are promising quantum sensors for their long spin coherence time under ambient conditions. However, their spin resonances are relatively insensitive to non-magnetic parameters such as temperature. A magnetic-nanoparticle-nanodiamond hybrid thermometer, where the temperature change is converted to the magnetic field variation near the Curie temperature, was demonstrated to have enhanced temperature sensitivity ($11{\rm{\;mK\;H}}{{\rm{z}}^{ - 1/2}}$) [Phys. Rev. X 8, 011042 (2018)], but the sensitivity was limited by the large spectral broadening of ensemble spins in nanodiamonds. To overcome this limitation, here we show an improved design of a hybrid nanothermometer using a single NV center in a diamond nanopillar coupled with a single magnetic nanoparticle of copper-nickel alloy, and demonstrate a temperature sensitivity of $76{\rm{\;\mu K\;H}}{{\rm{z}}^{ - 1/2}}$. This hybrid design enables detection of 2 millikelvin temperature changes with temporal resolution of 5 milliseconds. The ultra-sensitive nanothermometer offers a new tool to investigate thermal processes in nanoscale systems.

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Highlights from the Asia Pacific Region

Asia Pacific Physics Newsletter ◽

10.1142/s2251158x13000271 ◽

2013 ◽

Vol 02 (02) ◽

pp. 29-46

Author(s):

APPN Editorial Office

Keyword(s):

Information Technologies ◽

Room Temperature ◽

Spatial Separation ◽

Coherence Time ◽

Nitrogen Vacancy ◽

Asia Pacific ◽

Ambient Conditions ◽

Asia Pacific Region ◽

Quantum Bits ◽

Traditional Approaches

Quantum information technologies hold the promise of greatly outperforming traditional approaches in, e.g., cryptography, metrology and simulation. However, the ultimate goal of realizing scalable quantum computing has so far remained elusive, largely owing to the formidable difficulty in "wiring up" suitable quantum bits (qubits). In recent years, individual nitrogen-vacancy (NV-) defects in diamond have emerged as one of the most promising candidates for a solidstate qubit for two reasons. First, they possess the longest observed room-temperature coherence time of an electron spin (the qubit) to date; second, their spin can be initialized and measured with a nanoscale resolution using optical techniques under ambient conditions. However, interconnecting different NV- centres remains a big challenge. This problem is further exacerbated by the need for a large spatial separation between adjacent qubits, required for individual qubit addressability.

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Decoherence-protected quantum register of nuclear spins in diamond

Quantum Science and Technology ◽

10.1088/2058-9565/ac49df ◽

2022 ◽

Author(s):

Francisco Javier González ◽

Raúl Coto

Keyword(s):

Quantum Information ◽

Coherence Time ◽

Nitrogen Vacancy ◽

Nuclear Spins ◽

Practical Applications ◽

Quantum Register ◽

Nitrogen Vacancy Center ◽

Simultaneous Control ◽

Gate Time ◽

And Control

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.

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Quantum metrology with single spins in diamond under ambient conditions

National Science Review ◽

10.1093/nsr/nwx121 ◽

2017 ◽

Vol 5 (3) ◽

pp. 346-355 ◽

Cited By ~ 1

Author(s):

Ming Chen ◽

Chao Meng ◽

Qi Zhang ◽

Changkui Duan ◽

Fazhan Shi ◽

...

Keyword(s):

Electric Fields ◽

Environmental Changes ◽

Coherence Time ◽

Quantum Systems ◽

Nitrogen Vacancy ◽

Quantum Metrology ◽

Ambient Conditions ◽

Quantum Bits ◽

Temperature Strain ◽

Physical Quantities

Abstract The detection of single quantum systems can reveal information that would be averaged out in traditional techniques based on ensemble measurements. The nitrogen-vacancy (NV) centers in diamond have shown brilliant prospects of performance as quantum bits and atomic sensors under ambient conditions, such as ultra-long coherence time, high fidelity control and readout of the spin state. In particular, the sensitivity of the NV center spin levels to external environmental changes makes it a versatile detector capable of measuring various physical quantities, such as temperature, strain, electric fields and magnetic fields. In this paper, we review recent progress in NV-based quantum metrology, and speculate on its future.

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Sensing Electrochemical Signals Using a Nitrogen-Vacancy Center in Diamond

Nanomaterials ◽

10.3390/nano11020358 ◽

2021 ◽

Vol 11 (2) ◽

pp. 358

Author(s):

Hossein T. Dinani ◽

Enrique Muñoz ◽

Jeronimo R. Maze

Keyword(s):

Electric Field ◽

Electron Spin ◽

Electrolyte Solution ◽

High Sensitivity ◽

Theoretical Work ◽

Coherence Time ◽

Nitrogen Vacancy ◽

Local Concentration ◽

Concentration Of Ions ◽

Nv Center

Chemical sensors with high sensitivity that can be used under extreme conditions and can be miniaturized are of high interest in science and industry. The nitrogen-vacancy (NV) center in diamond is an ideal candidate as a nanosensor due to the long coherence time of its electron spin and its optical accessibility. In this theoretical work, we propose the use of an NV center to detect electrochemical signals emerging from an electrolyte solution, thus obtaining a concentration sensor. For this purpose, we propose the use of the inhomogeneous dephasing rate of the electron spin of the NV center (1/T2★) as a signal. We show that for a range of mean ionic concentrations in the bulk of the electrolyte solution, the electric field fluctuations produced by the diffusional fluctuations in the local concentration of ions result in dephasing rates that can be inferred from free induction decay measurements. Moreover, we show that for a range of concentrations, the electric field generated at the position of the NV center can be used to estimate the concentration of ions.

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Optically addressable nuclear spins in a solid with a six-hour coherence time

Nature ◽

10.1038/nature14025 ◽

2015 ◽

Vol 517 (7533) ◽

pp. 177-180 ◽

Cited By ~ 268

Author(s):

Manjin Zhong ◽

Morgan P. Hedges ◽

Rose L. Ahlefeldt ◽

John G. Bartholomew ◽

Sarah E. Beavan ◽

...

Keyword(s):

Coherence Time ◽

Nuclear Spins

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Teleportation of a controlled-NOT gate for photon and electron-spin qubits assisted by the nitrogen-vacancy center

Quantum Information and Computation ◽

10.26421/qic15.15-16-9 ◽

2015 ◽

Vol 15 (15&16) ◽

pp. 1397-1419

Author(s):

Ming-Xing Luo ◽

Hui-Ran Li

Keyword(s):

Electron Spin ◽

Spin System ◽

Room Temperature ◽

Coherence Time ◽

Nitrogen Vacancy ◽

Cnot Gate ◽

Long Distance ◽

Two Photon ◽

Nitrogen Vacancy Center ◽

Vacancy Center

Teleportations of quantum gates are very important in the construction of quantum network and teleportation-based model of quantum computation. Assisted with nitrogenvacancy centers, we propose several schemes to teleport the quantum CNOT gate. Deterministic CNOT gate may be implemented on a remote two-photon system, remote two electron-spin system, hybrid photon-spin system or hybrid spin-photon system. Each photon only interacts with one spin each time. Moreover, quantum channel may be constructed by all combinations of the photon or electron-spin entanglement, or their hybrid entanglement. Since these electron-spin systems have experimentally shown a long coherence time even at the room temperature, our schemes provide useful ways for long-distance quantum applications.

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