AUTHORS: Dionisis Stefanatos, Vasilios Karanikolas, Nikos Iliopoulos, Emmanuel Paspalakis

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ABSTRACT: We propose and analyze fast spin initialization for a quantum dot in the Voigt geometry by placing it near a graphene layer. We show that high levels of fidelity, significantly larger than in the case of the quantum dot without the layer, can be quickly obtained due to the anisotropy of the enhanced spontaneous decay rates of the quantum dot near the graphene layer. We initially obtain these results by using a continuous wave optical field with constant control amplitude. We also use state of the art numerical optimal control to find the time-dependent electric field which maximizes the final fidelity for the same short duration as in the previous case. A better fidelity is obtained with this method

KEYWORDS: Quantum control, numerical optimal control, quantum dot, spin initialization, Voigt geometry, optical pumping, spin dynamics

REFERENCES:

[1] R. J. Warburton, Single spins in self-assembled quantum dots, Nat. Mater. 12, 2013, pp. 483– 493.

[2] W. B. Gao, A. Imamoglu, H. Bernien, and R. Hanson, Coherent manipulation, measurement and entanglement of individual solid-state spins using optical fields, Nat. Photon. 9, 2015, pp. 363–373. Nikos Iliopoulos, Emmanuel Paspalakis E-ISSN: 2224-2856 304 Volume 14, 2019

[3] C. Emary, X. Xu, D. G. Steel, S. Saikin, and L. J. Sham, Fast initialization of the spin state of an electron in a quantum dot in the Voigt configuration, Phys. Rev. Lett. 98, 2007, art. no. 047401.

[4] S. E. Economou and T. L. Reinecke, Theory of fast optical spin rotation in a quantum dot based on geometric phases and trapped states, Phys. Rev. Lett. 99, 2007, art. no. 217401.

[5] V. Loo, L. Lanco, O. Krebs, P. Senellart, and P. Voisin, Single-shot initialization of electron spin in a quantum dot using a short optical pulse, Phys. Rev. B 83, 2011, art. no. 033301.

[6] A. Majumdar, P. Kaer, M. Bajcsy, E. D. Kim, K. G. Lagoudakis, A. Rundquist, and J. Vuckovic, Proposed coupling of an electron spin in a semiconductor quantum dot to a nanosize optical cavity, Phys. Rev. Lett. 111, 2013, art. no. 027402.

[7] M. A. Anton, F. Carre ´ no, S. Melle, ˜ O. G. Calderon, E. Cabrera-Granado, and ´ M. R. Singh, Optical pumping of a single hole spin in a p-doped quantum dot coupled to a metallic nanoparticle, Phys. Rev. B 87, 2013, art. no. 195303.

[8] Y. Peng, Z.-Y. Yun, Y. Liu, T.–S. Wu, W. Zhang, and H. Ye, Fast initialization of hole spin in a quantum dot-metal surface hybrid system, Physica B 470–471, 2015, pp. 1–5.

[9] F. Carreno, F. Arrieta-Y ˜ a´nez, and M. A. Ant ˜ on, ´ Spin initialization of a p-doped quantum dot coupled to a bowtie nanoantenna, Opt. Commun. 343, 2015, pp. 97–106.

[10] E. Paspalakis, S. E. Economou, and F. Carreno, ˜ Adiabatically preparing quantum dot spin states in the Voigt geometry, J. Appl. Phys. 125, 2019, art. no. 024305.

[11] D. P. DiVincenzo, The physical implementation of quantum computation Fortsch. Phys. 48, 2000, pp. 771–783.

[12] F. H. L. Koppens, D. E. Chang, and F. J. Garc´ıa de Abajo, Graphene plasmonics: a platform for strong lightmatter interactions, Nano Lett. 11, 2011, pp. 3370–3377.

[13] G. W. Hanson, E. Forati, W. Linz, and A. B. Yakovlev, Excitation of terahertz surface plasmons on graphene surfaces by an elementary dipole and quantum emitter: Strong electrodynamic effect of dielectric support, Phys. Rev. B 86, 2012, art. no. 235440.

[14] V. Karanikolas and E. Paspalakis, Plasmoninduced quantum interference near carbon nanostructures, J. Phys. Chem. C 122, 2018, pp. 14788-14795.

[15] W. Fang, G.–X. Li, and Y. P. Yang, Controllable radiation properties of a driven exciton-biexciton quantum dot couples to a graphene sheet, Opt. Express 26, 2018, pp. 29561–29587.

[16] P. Harrison, Quantum Wells, Wires and Dots: Theoretical and Computational Physics of Semiconductor Nanostructures, 3rd Edition, Wiley, 2009.

[17] C. Delerue and M. Lannoo, Nanostructures: Theory and Modelling, Springer, 2004.

[18] G. Bester, Electronic excitations in nanostructures: an empirical pseudopotential based approach J. Phys.: Condens. Matter 21, 2009, art. no. 023202.

[19] S. M. Reimann and M. Manninen, Electronic structure of quantum dots Rev. Mod. Phys. 74, 2002, pp. 1283–1342.

[20] F. Bonnans, P. Martinon, D. Giorgi, V. Grelard, ´ S. Maindrault, and O. Tissot, BOCOP: an open source toolbox for optimal control, (INRIASaclay, Ile de France, 2017).

[21] M. Palmero, S. Wang, D. Guery-Odelin, J.– ´ S. Li, and J. G. Muga, Shortcuts to adiabaticity for an ion in a rotating radially-tight trap, New J. Phys. 18, 2016, art. no. 043014.

[22] Q. Zhang, X. Chen, and D. Guery-Odelin, Re- ´ verse engineering protocols for controlling spin dynamics, Sci. Rep. 7, 2017, art. no. 15814.

[23] Y. Yan, Y.–C. Li, A. Kinos, A. Walther, C. Shi, L. Rippe, J. Moser, S. Kroll, and X. Chen, In- ¨ verse engineering of shortcut pulses for high fidelity initialization on qubits closely spaced in frequency, Opt. Express 27, 2019, pp. 8267– 8282.

[24] D. Stefanatos and E. Paspalakis, Efficient generation of the triplet Bell state between coupled spins using transitionless quantum driving and optimal control, Phys. Rev. A 99, 2019, art. no. 022327.