Quantum Entanglement and Spin Control in Silicon Nanocrystal

Abstract

Selective coherence control and electrically mediated exchange coupling of single electron spin between triplet and singlet states using numerically derived optimal control of proton pulses is demonstrated. We obtained spatial confinement below size of the Bohr radius for proton spin chain FWHM. Precise manipulation of individual spins and polarization of electron spin states are analyzed via proton induced emission and controlled population of energy shells in pure 29Si nanocrystal. Entangled quantum states of channeled proton trajectories are mapped in transverse and angular phase space of 29Si axial channel alignment in order to avoid transversal excitations. Proton density and proton energy as impact parameter functions are characterized in single particle density matrix via discretization of diagonal and nearest off-diagonal elements. We combined high field and low densities (1 MeV/92 nm) to create inseparable quantum state by superimposing the hyperpolarizationed proton spin chain with electron spin of 29Si. Quantum discretization of density of states (DOS) was performed by the Monte Carlo simulation method using numerical solutions of proton equations of motion. Distribution of gaussian coherent states is obtained by continuous modulation of individual spin phase and amplitude. Obtained results allow precise engineering and faithful mapping of spin states. This would provide the effective quantum key distribution (QKD) and transmission of quantum information over remote distances between quantum memory centers for scalable quantum communication network. Furthermore, obtained results give insights in application of channeled protons subatomic microscopy as a complete versatile scanning-probe system capable of both quantum engineering of charged particle states and characterization of quantum states below diffraction limit linear and in-depth resolution.PACS numbers: 03.65.Ud, 03.67.Bg, 61.85.+p, 67.30.hj

Characterization of electron density of states in laser-superposed channeling regime

“…To describe inner-shell ionization and excitation of atoms as a function of the impact parameter (Gemmell, 1974;Appleton et al, 1972), we have applied semi-classical method of the coupled-channel calculations (Bransden et al, 1985;Thompson, 1988), where the projectile following a classical trajectory provides a time-dependent electrostatic perturbation on the target electrons. The channeled proton distributions are double-mapped in the phase space: first in the coordination plane, x ′ − y ′ , then in the scattering-angle plane, ϑ x − θ y (Berec, 2012), in accordance with chosen value of the crystal thickness, L and the tilt angle (φ). The channeled proton distributions are double-mapped in the phase space: first in the coordination plane, x ′ − y ′ , then in the scattering-angle plane, ϑ x − θ y (Berec, 2012), in accordance with chosen value of the crystal thickness, L and the tilt angle (φ).…”

“…Such nanoscale precision scanning technique is based on dynamical analysis of an electron wave packet by creating a highly resolved image in real conditions with produced detailed map of discrete inter-atom positions (Berec, 2012). The acceleration process occurs within the laser pulse duration only.…”

“…By varying the initial tilts of the proton beam, we performed a numerical pump-probe measurement of the electron wavepacket motion (Berec, 2012). By varying the initial tilts of the proton beam, we performed a numerical pump-probe measurement of the electron wavepacket motion (Berec, 2012).…”

“…The analysis of the proton scattering process in question is carried out via the mapping of the impact parameter plane to the transverse position plane (Berec, 2012;Gemmell, 1974), in accordance with the chosen values of φ and the crystal thickness L. The corresponding reduced crystal thickness is Λ = f r L/v 0 where f r = 5.94 × 10 13 Hz and v 0 is the initial proton velocity. The nonlinear map J r (x, y, φ, Λ) transforms the original phase space point (x, y) into the phase space point where the projection is measured.…”

“…Recently, we have described the quantum model for the subatomic confinement (Berec, 2012) of the proton beam, which is channeled along the axial <100> axis of a silicon nanocrystal. By measuring the transverse projection of electron densities inside nanocrystal, we have analyzed the crosssection for the process of proton induced X-ray emission with MeV proton energies as a function of the proton impact parameters.…”