@article{Hopper2019,

title = {Real-Time Charge Initialization of Diamond Nitrogen-Vacancy Centers for Enhanced Spin Readout},

author = {D A Hopper and J D Lauigan and T -Y Huang and L C Bassett},

url = {https://arxiv.org/abs/1907.08741

https://journals.aps.org/prapplied/abstract/10.1103/PhysRevApplied.13.024016

https://medium.com/penn-engineering/penn-engineers-ensure-quantum-experiments-get-off-to-the-right-start-bbe6f3382cb},

year  = {2020},

date = {2020-02-07},

journal = {Phys. Rev. Applied},

volume = {13},

pages = {024016},

abstract = {Selected as an Editor's Suggestion.



A common impediment to qubit performance is imperfect state initialization. In the case of the diamond nitrogen-vacancy (NV) center, the initialization fidelity is limited by fluctuations in the defect's charge state during optical pumping. Here, we use real-time control to deterministically initialize the NV center's charge state at room temperature. We demonstrate a maximum charge initialization fidelity of 99.4±0.1% and present a quantitative model of the initialization process that allows for systems-level optimization of the spin-readout signal-to-noise ratio. Even accounting for the overhead associated with the initialization sequence, increasing the charge initialization fidelity from the steady-state value of 75% near to unity allows for a factor-of-two speedup in experiments while maintaining the same signal-to-noise-ratio. In combination with high-fidelity readout based on spin-to-charge conversion, real-time initialization enables a factor-of-20 speedup over traditional methods, resulting in an ac magnetic sensitivity of 1.3 nT/Hz1/2 for our single NV-center spin. The real-time control method is immediately beneficial for quantum sensing applications with NV centers as well as probing charge-dependent physics, and it will facilitate protocols for quantum feedback control over multi-qubit systems.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Bassett2019b,

title = {Quantum defects by design},

author = {L. C. Bassett and A. Alkauskas and A. L. Exarhos and K.-M. C. Fu},

url = {https://www.degruyter.com/view/journals/nanoph/8/11/article-p1867.xml},

year  = {2019},

date = {2019-10-04},

journal = {Nanophotonics},

volume = {8},

number = {11},

abstract = {Part of Special Issue on Quantum Nanophotonics in Emerging Materials.



Miniaturization of electronic and opto-electronic semiconductor devices has been happening ever since the first such devices appeared. Eventually, one can envision a device that is composed of just a few atoms. As these atoms ideally should not float in free space, but should be embedded in a solid-state matrix, this naturally brings one to the concept of a point defect (an impurity atom or complex of atoms) as the ultimate electronic or opto-electronic device. At such tiny length scales the behavior of physical systems is governed by the laws of quantum mechanics. Therefore, it is no surprise that an increasing number of point defects are being considered as building blocks for various applications in the field of quantum information science; more specifically, in quantum sensing, quantum communication, and quantum computing [1], [2], [3], [4]. We refer to these desirable defects as quantum point defects (QPDs). Prominent examples include the nitrogen-vacancy (NV) center in diamond, the silicon-vacancy (SiV) center in diamond, the divacancy in silicon carbide, and rare-earth impurities in complex oxides.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}