420 research outputs found
Ion-trap quantum information processing: experimental status
Atomic ions trapped in ultra-high vacuum form an especially well-understood
and useful physical system for quantum information processing. They provide
excellent shielding of quantum information from environmental noise, while
strong, well-controlled laser interactions readily provide quantum logic gates.
A number of basic quantum information protocols have been demonstrated with
trapped ions. Much current work aims at the construction of large-scale
ion-trap quantum computers using complex microfabricated trap arrays. Several
groups are also actively pursuing quantum interfacing of trapped ions with
photons.Comment: review article for Frontiers of Physics replace corrupted TeX fil
Theory of Quantum Path Computing with Fourier Optics and Future Applications for Quantum Supremacy, Neural Networks and Nonlinear Schr\"odinger Equations
The scalability, error correction and practical problem solving are important
challenges for quantum computing (QC) as more emphasized by quantum supremacy
(QS) experiments. Quantum path computing (QPC), recently introduced for linear
optic based QCs (LOQCs) as an unconventional design, targets to obtain
scalability and practical problem solving. It samples the intensity from the
interference of exponentially increasing number of propagation paths obtained
in multi-plane diffraction (MPD) of classical particle sources. QPC exploits
MPD based quantum temporal correlations of the paths and freely entangled
projections a<t different time instants, for the first time, with the classical
light source and intensity measurement while not requiring photon interactions
or single photon sources and receivers. In this article, photonic QPC is
defined, theoretically modeled and numerically analyzed for arbitrary Fourier
optical or quadratic phase set-ups while utilizing both Gaussian and
Hermite-Gaussian source laser modes. Problem solving capabilities already
including partial sum of Riemann theta functions are extended. Important future
applications, implementation challenges and open issues such as universal
computation and quantum circuit implementations determining the scope of QC
capabilities are discussed. The applications include QS experiments reaching
more than Feynman paths, quantum neuron implementations and solutions
of nonlinear Schr\"odinger equation.Comment: This is the author accepted copy of the original article published
and fully edited in https://www.nature.com/articles/s41598-020-67364-
Technologies for trapped-ion quantum information systems
Scaling-up from prototype systems to dense arrays of ions on chip, or vast
networks of ions connected by photonic channels, will require developing
entirely new technologies that combine miniaturized ion trapping systems with
devices to capture, transmit and detect light, while refining how ions are
confined and controlled. Building a cohesive ion system from such diverse parts
involves many challenges, including navigating materials incompatibilities and
undesired coupling between elements. Here, we review our recent efforts to
create scalable ion systems incorporating unconventional materials such as
graphene and indium tin oxide, integrating devices like optical fibers and
mirrors, and exploring alternative ion loading and trapping techniques.Comment: 19 pages, 18 figure
A micro-optical module for multi-wavelength addressing of trapped ions
The control of large-scale quantum information processors based on arrays of
trapped ions requires a means to route and focus multiple laser beams to each
of many trapping sites in parallel. Here, we combine arrays of fibres, 3D
laser-written waveguides and diffractive microlenses to demonstrate the
principle of a micro-optic interconnect suited to this task. The module is
intended for use with an ion microtrap of 3D electrode geometry. It guides ten
independent laser beams with unique trajectories to illuminate a pair of
spatially separated target points. Three blue and two infrared beams converge
to overlap precisely at each desired position. Typical relative crosstalk
intensities in the blue are and the average insertion loss
across all channels is dB. The module occupies times less
volume than a conventional bulk-optic equivalent and is suited to different ion
species
Absorption imaging of a single atom
Absorption imaging has played a key role in the advancement of science from
van Leeuwenhoek's discovery of red blood cells to modern observations of dust
clouds in stellar nebulas and Bose-Einstein condensates. Here we show the first
absorption imaging of a single atom isolated in vacuum. The optical properties
of atoms are thoroughly understood, so a single atom is an ideal system for
testing the limits of absorption imaging. A single atomic ion was confined in
an RF Paul trap and the absorption imaged at near wavelength resolution with a
phase Fresnel lens. The observed image contrast of 3.1(3)% is the maximum
theoretically allowed for the imaging resolution of our setup. The absorption
of photons by single atoms is of immediate interest for quantum information
processing (QIP). Our results also point out new opportunities in imaging of
light-sensitive samples both in the optical and x-ray regimes.Comment: Accepted to Nature Commu
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