Room-temperature entanglement between single defect spins in diamond

By F. Dolde, I. Jakobi, B. Naydenov, N. Zhao, S. Pezzagna, C. Trautmann, J. Meijer, P. Neumann, Fedor Jelezko, J. Wrachtrup. Nature Physics, 2012

443 citations recorded by the source corpus.

Engineered defects in the diamond lattice hold promise for the storage and manipulation of quantum information. Entanglement between the electron and nuclear spins of two such defects is demonstrated at room temperature. Entanglement is the central yet fleeting phenomenon of quantum physics. Once being considered a peculiar counter-intuitive property of quantum theory1, it has developed into the most central element of quantum technology. Consequently, there have been a number of experimental demonstrations of entanglement between photons2, atoms3, ions4 and solid-state systems such as spins or quantum dots5,6,7, superconducting circuits8,9 and macroscopic diamond10. Here we experimentally demonstrate entanglement between two engineered single solid-state spin quantum bits (qubits) at ambient conditions. Photon emission of defect pairs reveals ground-state spin correlation. Entanglement (fidelity = 0.67±0.04) is proved by quantum state tomography. Moreover, the lifetime of electron spin entanglement is extended to milliseconds by entanglement swapping to nuclear spins. The experiments mark an important step towards a scalable room-temperature quantum device being of potential use in quantum information processing as well as metrology.

Subfields: Atomic and Molecular Physics, and Optics, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/8bb1067bf2197e51391d54c3027b0daf73b54a87

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In Atomic and Molecular Physics, and Optics

1. M. Turner
2. J. Barry
3. J. Schloss
4. B. Shore
5. A. Rangelov
6. C. Hart
7. L. Pham
8. K. Bergmann

In Materials Chemistry

1. M. Turner
2. R. Walsworth
3. C. Hart
4. J. Schloss
5. J. Barry
6. L. Pham
7. E. Bauch
8. P. Nealey

Citations in the corpus

• Long-range spin wave mediated control of defect qubits in nanodiamonds (2017, background): “Many QIP applications[7, 8] rely on dipolar interactions between the qubits, requiring them to be within a few nanometers from each other while still allowing for their individual manipulation with optical and microwave fields.”
• Sensitivity optimization for NV-diamond magnetometry (2019, methodology): “Controlled coupling of NVspin pairs (Bernien et al., 2013; Dolde et al., 2013; Hensen et al., 2015; Jakobi et al., 2016; Neumann et al., 2010b; Yamamoto et al., 2013a) has been demonstrated; however, applying entanglement-enhanced techniques to larger ensembles is expected to be challenging.”
• Stimulated Raman adiabatic passage in physics, chemistry, and beyond (2016, background): “…state transfer between electron and nuclear spins (Childress et al., 2006; Dutt et al., 2007), spin entanglement mediated by dipole coupling, and spin-photon entanglement (Bernien et al., 2013; Dolde et al., 2013; Neumann et al., 2008; Sipahigil et al., 2012; Togan et al., 2010) have been observed.”
• Quantum optimal control in quantum technologies. Strategic report on current status, visions and goals for research in Europe (2022, background): “In particular, they satisfy – to some extent – the DiVincenzo criteria for quantum computation: it is possible to individuate well defined energy levels to encode qubits states that can be initialized and manipulated via laser excitation and microwaves; the system state can be measured via fluoresce”
• Nonlinear optical signals and spectroscopy with quantum light (2016, background): “Most common types of entanglement are: their spin (Dolde et al., 2013), polarization (Shih and Alley, 1988), position and momentum (Howell et al., 2004), time and energy (Tittel et al., 1999), etc. Entangled photon pairs constitute an invaluable tool in fundamental tests of quantum mechanics - most…”
• Modular entanglement of atomic qubits using photons and phonons (2014, background): “native local interactions in many physical platforms, such as trapped atomic ions through their Coulomb interaction [5], Rydberg atoms through their electric dipoles [7, 8], nitrogen-vacancy centers in diamond through their magnetic dipoles [9], and superconducting Joseph-”