443,178 research outputs found
Integrated photonic qubit quantum computing on a superconducting chip
We study a quantum computing system using microwave photons in transmission
line resonators on a superconducting chip as qubits. We show that all control
necessary for quantum computing can be implemented by coupling to Josephson
devices on the same chip, and take advantage of their strong inherent
nonlinearities to realize qubit interactions. We analyze the gate error rate to
demonstrate that our scheme is realistic even for Josephson devices with
limited decoherence times. A conceptually innovative solution based on existing
technologies, our scheme provides an integrated and scalable approach to the
next key milestone for photonic qubit quantum computing.Comment: 5 pages, 3 figure
An Architectural Framework for Collaboration of Heterogeneous Communication Devices Using WAP and Mobile Device Augmented(MDA)Gateway Integration
Within the last couple of years, the challenge of displaying collaborative multimedia
information has become very important with the large diversity of communication devices
such as Personal Computers, laptops, notebooks and handheld devices. The shared data
and information may be presented with different views depending on the communication
device used by a particular collaborator. The use of various web tools (HTML, WML etc)
offers some solutions to the problem but if the target application requires more complex
features such as rich multimedia data than is manageable using HTML or WML format,
something else need to be done. In this paper, we propose a framework that integrates WAP
and MDA Gateway to support collaboration among virtual teams and nomadic workers
using heterogeneous communication devices. We then discuss an approach for augmenting
mobile device small screen capabilities with surrounding large screen display device
Controlling phonons and photons at the wavelength-scale: silicon photonics meets silicon phononics
Radio-frequency communication systems have long used bulk- and
surface-acoustic-wave devices supporting ultrasonic mechanical waves to
manipulate and sense signals. These devices have greatly improved our ability
to process microwaves by interfacing them to orders-of-magnitude slower and
lower loss mechanical fields. In parallel, long-distance communications have
been dominated by low-loss infrared optical photons. As electrical signal
processing and transmission approaches physical limits imposed by energy
dissipation, optical links are now being actively considered for mobile and
cloud technologies. Thus there is a strong driver for wavelength-scale
mechanical wave or "phononic" circuitry fabricated by scalable semiconductor
processes. With the advent of these circuits, new micro- and nanostructures
that combine electrical, optical and mechanical elements have emerged. In these
devices, such as optomechanical waveguides and resonators, optical photons and
gigahertz phonons are ideally matched to one another as both have wavelengths
on the order of micrometers. The development of phononic circuits has thus
emerged as a vibrant field of research pursued for optical signal processing
and sensing applications as well as emerging quantum technologies. In this
review, we discuss the key physics and figures of merit underpinning this
field. We also summarize the state of the art in nanoscale electro- and
optomechanical systems with a focus on scalable platforms such as silicon.
Finally, we give perspectives on what these new systems may bring and what
challenges they face in the coming years. In particular, we believe hybrid
electro- and optomechanical devices incorporating highly coherent and compact
mechanical elements on a chip have significant untapped potential for
electro-optic modulation, quantum microwave-to-optical photon conversion,
sensing and microwave signal processing.Comment: 26 pages, 5 figure
QYMSYM: A GPU-Accelerated Hybrid Symplectic Integrator That Permits Close Encounters
We describe a parallel hybrid symplectic integrator for planetary system
integration that runs on a graphics processing unit (GPU). The integrator
identifies close approaches between particles and switches from symplectic to
Hermite algorithms for particles that require higher resolution integrations.
The integrator is approximately as accurate as other hybrid symplectic
integrators but is GPU accelerated.Comment: 17 pages, 2 figure
Geometrically-controlled polarisation processing in an integrated photonic platform
The polarisation of light is a powerful and widely used degree of freedom to
encode information, both in classical and quantum applications. In particular,
quantum information technologies based on photons are being revolutionised by
the use of integrated photonic circuits. It is therefore very important to be
able to manipulate the polarisation of photons in such circuits. We
experimentally demonstrate the fabrication by femtosecond laser micromachining
of components such as polarisation insensitive or polarising directional
couplers, operating at 1550 nm wavelength, where the two opposite behaviours
are achieved just by controlling the geometric layout of the photonic circuits,
being the waveguides fabricated with the same irradiation recipe. We expect to
employ this approach in complex integrated photonic devices, capable of a full
control of the photons polarisation for quantum cryptography, quantum
computation and quantum teleportation experiments.Comment: 9 pages, 7 figure
Micro-Electro-Mechanical-Systems (MEMS) and Fluid Flows
The micromachining technology that emerged in the late 1980s can provide micron-sized sensors and actuators. These micro transducers are able to be integrated with signal conditioning and processing circuitry to form micro-electro-mechanical-systems (MEMS) that can perform real-time distributed control. This capability opens up a new territory for flow control research. On the other hand, surface effects dominate the fluid flowing through these miniature mechanical devices because of the large surface-to-volume ratio in micron-scale configurations. We need to reexamine the surface forces in the momentum equation. Owing to their smallness, gas flows experience large Knudsen numbers, and therefore boundary conditions need to be modified. Besides being an enabling technology, MEMS also provide many challenges for fundamental flow-science research
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