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Quantum Information Processing (quantum + information_processing)

Distribution by Scientific Domains
Chemistry66%

Selected Abstracts

Spin-Based Optical Quantum Information Processing

ISRAEL JOURNAL OF CHEMISTRY, Issue 4 2006
Ehoud Pazy
We shall present a review of semiconductor spin-based implementation schemes for the realization of quantum information/computation solid-state devices. After briefly describing the fundamentals of quantum computation theory, we shall introduce and discuss potential implementation schemes based on the spin degrees of freedom in semiconductor nanostructures. More specifically, we shall describe an implementation scheme for quantum information processing in which the spin degrees of freedom of electrons confined to a quantum dot are the computational degrees of freedom, and spins are manipulated/controlled through interaction between trionic states created by interband optical transitions by ultrafast sequences of multicolor laser pulses. We will also review briefly an adiabatic method for operating the two-qubit gate that avoids the main imperfections present in real quantum dots: exciton decay, hole mixing, and phonon decoherence. [source]

Geometric algebra and transition-selective implementations of the controlled-NOT gate

CONCEPTS IN MAGNETIC RESONANCE, Issue 1 2004
Timothy F. Havel
Geometric algebra provides a complete set of simple rules for the manipulation of product operator expressions at a symbolic level, without any explicit use of matrices. This approach can be used not only to describe the state and evolution of a spin system, but also to derive the effective Hamiltonian and associated propagator in full generality. In this article, we illustrate the use of geometric algebra via a detailed analysis of transition-selective implementations of the controlled-NOT gate, which plays a key role in NMR-based quantum information processing. In the appendices, we show how one can also use geometric algebra to derive tight bounds on the magnitudes of the errors associated with these implementations of the controlled-NOT. © 2004 Wiley Periodicals, Inc. Concepts Magn Reson Part A 23A: 49,62, 2004 [source]

Spin-Based Optical Quantum Information Processing

ISRAEL JOURNAL OF CHEMISTRY, Issue 4 2006
Ehoud Pazy
We shall present a review of semiconductor spin-based implementation schemes for the realization of quantum information/computation solid-state devices. After briefly describing the fundamentals of quantum computation theory, we shall introduce and discuss potential implementation schemes based on the spin degrees of freedom in semiconductor nanostructures. More specifically, we shall describe an implementation scheme for quantum information processing in which the spin degrees of freedom of electrons confined to a quantum dot are the computational degrees of freedom, and spins are manipulated/controlled through interaction between trionic states created by interband optical transitions by ultrafast sequences of multicolor laser pulses. We will also review briefly an adiabatic method for operating the two-qubit gate that avoids the main imperfections present in real quantum dots: exciton decay, hole mixing, and phonon decoherence. [source]

Today's challenges in quantum dot materials research for tomorrow's quantum functional devices

PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 8 2007
Richard Nötzel
Abstract Size, shape, position control, and self-organized lateral ordering of epitaxial semiconductor quantum dot (QD) arrays are demonstrated. This constitutes the prerequisite for the ultimate control of the electronic and optical properties of man-made semiconductor heterostructures at the single and multiple charge, spin, and photon level, including their quantum mechanical and electromagnetic interactions in view of applications such as quantum information processing and computing. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Non-Blinking Semiconductor Colloidal Quantum Dots for Biology, Optoelectronics and Quantum Optics

CHEMPHYSCHEM, Issue 6 2009
Piernicola Spinicelli
Abstract Twinkle, twinkle: The blinking of semiconductor colloidal nanocrystals is the main inconvenience of these bright nanoemitters. There are various approaches for obtaining non-blinking nanocrystals, one of which is to grow a thick coat of CdS on the CdSe core (see picture). Applications of this method in the fields of optoelectronic devices, biologic labelling and quantum information processing are discussed. The blinking of semiconductor colloidal nanocrystals is the main inconvenience of these bright nanoemitters. For some years, research on this phenomenon has demonstrated the possibility to progress beyond this problem by suppressing this fluorescence intermittency in various ways. After a brief overview on the microscopic mechanism of blinking, we review the various approaches used to obtain non-blinking nanocrystals and discuss the commitment of this crucial improvement to applications in the fields of optoelectronic devices, biologic labelling and quantum information processing. [source]

Entangling Light in its Spatial Degrees of Freedom with Four-Wave Mixing in an Atomic Vapor

CHEMPHYSCHEM, Issue 5 2009
Vincent Boyer Dr.
Abstract Nonlinearities in atomic vapors allow the production of "entangled images",beams of light whose transverse light distributions exhibit localized correlations in their unavoidable quantum fluctuations (see picture). These spatially entangled beams may prove useful to reduce the noise in absorption imaging and beam positioning below the quantum noise level, as well as for quantum information applications. The entanglement properties of two beams of light can reside in subtle correlations that exist in the unavoidable quantum fluctuations of their amplitudes and phases. Recent advances in the generation of nonclassical light with four-wave mixing in an atomic vapor have permitted the production and the observation of entanglement that is localized in almost arbitrary transverse regions of a pair of beams. These multi-spatial-mode entangled beams may prove useful for an array of applications ranging from noise-free imaging and improved position sensing to quantum information processing. [source]