Nuclear spin based quantum information processing at high magnetic fields

Two kinds of thermal quantum correlations, measured respectively by quantum discord (QD) and the generalized negativity (GN), are studied for various magnetic fields, couplings, and temperatures in a two-qubit Heisenberg XYZ model. It is shown that QD and GN can exhibit a similar behavior in some regions of magnetic field, coupling, and temperature, while they behave in a contrary manner in other regions. For example, QD may increase with suitable magnetic fields, couplings, and temperature when GN decreases. QD is more robust against temperature than GN, and can reveal a kink at a suitable coupling at finite temperature while GN cannot. Moreover, a nearly unchanged QD or GN can be obtained in a large region of magnetic field, coupling, and temperature. These adjustable QD and GN via the varied magnetic field, coupling, and temperature may have significant applications in quantum information processing.

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PULSED ENDOR-BASED QUANTUM INFORMATION PROCESSING

International Journal of Quantum Information ◽

10.1142/s0219749905001377 ◽

2005 ◽

Vol 03 (supp01) ◽

pp. 197-204 ◽

Cited By ~ 17

Author(s):

ROBABEH RAHIMI ◽

KAZUNOBU SATO ◽

KOU FURUKAWA ◽

KAZUO TOYOTA ◽

DAISUKE SHIOMI ◽

...

Keyword(s):

Information Processing ◽

Quantum Information ◽

Electron Spin ◽

Nuclear Spin ◽

Quantum Information Processing ◽

Quantum Algorithms ◽

Double Resonance ◽

Electron Nuclear Double Resonance ◽

Preliminary Results ◽

Experimental Side

Pulsed Electron Nuclear DOuble Resonance (pulsed ENDOR) has been studied for realization of quantum algorithms, emphasizing the implementation of organic molecular entities with an electron spin and a nuclear spin for quantum information processing. The scheme has been examined in terms of quantum information processing. Particularly, superdense coding has been implemented from the experimental side and the preliminary results are represented as theoretical expectations.

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Giant titanium electron wave function in gallium oxide: A potential electron-nuclear spin system for quantum information processing

Physical Review B ◽

10.1103/physrevb.82.184414 ◽

2010 ◽

Vol 82 (18) ◽

Cited By ~ 7

Author(s):

Frédéric Mentink-Vigier ◽

Laurent Binet ◽

Gerard Vignoles ◽

Didier Gourier ◽

Hervé Vezin

Keyword(s):

Wave Function ◽

Information Processing ◽

Quantum Information ◽

Spin System ◽

Nuclear Spin ◽

Gallium Oxide ◽

Quantum Information Processing ◽

Electron Wave Function ◽

Electron Wave ◽

Nuclear Spin System

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CONTROLLING SPIN COHERENCE WITH SEMICONDUCTOR NANOSTRUCTURES

International Journal of Modern Physics B ◽

10.1142/s0217979208046165 ◽

2008 ◽

Vol 22 (01n02) ◽

pp. 111-112

Author(s):

DAVID D. AWSCHALOM

Keyword(s):

Information Processing ◽

Quantum Information ◽

Electron Spin ◽

Nuclear Spin ◽

Room Temperature ◽

Quantum Information Processing ◽

Spin Dynamics ◽

Spin Coherence ◽

Electron Spin Dynamics ◽

Coherent Spin

We present two emerging opportunities for manipulating and communicating coherent spin states in semiconductors. First, we show that semiconductor microcavities offer unique means of controlling light-matter interactions in confined geometries, resulting in a wide range of applications in optical communications and inspiring proposals for quantum information processing and computational schemes. Studies of spin dynamics in microcavities — a new and promising research field — have revealed novel effects such as polarization beats, stimulated spin scattering, and giant Faraday rotation. Here, we study the electron spin dynamics in optically-pumped GaAs microdisk lasers with quantum wells and interface-fluctuation quantum dots in the active region. In particular, we examine how the electron spin dynamics are modified by the stimulated emission in the disks, and observe an enhancement of the spin coherence time when the optical excitation is in resonance with a high quality ( Q ~ 5000) lasing mode.1 This resonant enhancement, contrary to expectations from the observed trend in the carrier recombination time, is then manipulated by altering the cavity design and dimensions. In analogy to devices based on excitonic coherence, this ability to engineer coherent interactions between electron spins and photons may provide novel pathways towards spin dependent quantum optoelectronics. In a second example, the nitrogen-vacancy (N-V) center in diamond has garnered interest as a room-temperature solid-state system not only for exploring electronic and nuclear spin phenomena but also as a candidate for spin-based quantum information processing. Spin coherence times of up to 50 microseconds have been reported for ensembles of N-V centers and a two-qubit gate utilizing the electron spin of a N-V center and the nuclear spin of a nearby C-13 atom has been demonstrated. Here, we present experiments using angle-resolved magneto-photoluminescence microscopy to investigate anisotropic spin interactions of single N-V centers in diamond at room temperature.2 Negative peaks in the photoluminescence intensity are observed as a function of both magnetic field magnitude and angle, and can be explained by coherent spin precession and anisotropic relaxation at spin-level anticrossings. Additionally, precise field alignment with the symmetry axis of a single N-V center reveals the resonant magnetic dipolar coupling of a single "bright" electron spin of an N-V center to small numbers of "dark" spins of nitrogen defects in its immediate vicinity, which are otherwise undetected by photoluminescence. Most recently, we are exploring the possibility of utilizing this magnetic dipole coupling between bright and dark spins to couple two spatially separated single N-V center spins by means of intermediate nitrogen spins. Note from Publisher: This article contains the abstract only.

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