1,139 research outputs found
Noise in Electron Devices
Contains a report on a research project.Lincoln Laboratory (Purchase Order DDL B-00368)United States ArmyUnited States NavyUnited States Air Force (Contract AF19(604)-7400
Generation and manipulation of squeezed states of light in optical networks for quantum communication and computation
We analyze a fiber-optic component which could find multiple uses in novel
information-processing systems utilizing squeezed states of light. Our approach
is based on the phenomenon of photon-number squeezing of soliton noise after
the soliton has propagated through a nonlinear optical fiber. Applications of
this component in optical networks for quantum computation and quantum
cryptography are discussed.Comment: 12 pages, 2 figures; submitted to Journal of Optics
Decoherence of Quantum-Enhanced Timing Accuracy
Quantum enhancement of optical pulse timing accuracy is investigated in the
Heisenberg picture. Effects of optical loss, group-velocity dispersion, and
Kerr nonlinearity on the position and momentum of an optical pulse are studied
via Heisenberg equations of motion. Using the developed formalism, the impact
of decoherence by optical loss on the use of adiabatic soliton control for
beating the timing standard quantum limit [Tsang, Phys. Rev. Lett. 97, 023902
(2006)] is analyzed theoretically and numerically. The analysis shows that an
appreciable enhancement can be achieved using current technology, despite an
increase in timing jitter mainly due to the Gordon-Haus effect. The decoherence
effect of optical loss on the transmission of quantum-enhanced timing
information is also studied, in order to identify situations in which the
enhancement is able to survive.Comment: 12 pages, 4 figures, submitte
Solvable glassy system: static versus dynamical transition
A directed polymer is considered on a flat substrate with randomly located
parallel ridges. It prefers to lie inside wide regions between the ridges. When
the transversel width is exponential in the
longitudinal length , there can be a large number of
available wide states. This ``complexity'' causes a phase transition from a
high temperature phase where the polymer lies in the widest lane, to a glassy
low temperature phase where it lies in one of many narrower lanes. Starting
from a uniform initial distribution of independent polymers, equilibration up
to some exponential time scale induces a sharp dynamical transition. When the
temperature is slowly increased with time, this occurs at a tunable
temperature. There is an asymmetry between cooling and heating. The structure
of phase space in the low temperature non-equilibrium glassy phase is of a
one-level tree.Comment: 4 pages revte
Preservation and Promotion of Opera Cultural Heritage: The Experience of La Scala Theatre
This paper focuses on music and music-related cultural heritage typically preserved by opera houses, starting from the experience achieved during the long-lasting collaboration between La Scala theater and the Laboratory of Music Informatics of the University of Milan. First, we will mention the most significant results achieved by the project in the fields of preservation, information retrieval and dissemination of cultural heritage through computer-based approaches. Moreover, we will discuss the possibilities offered by new technologies applied to the conservative context of an opera house, including: the multi-layer representation of music information to foster the accessibility of musical content also by non-experts; the adoption of 5G networks to deliver spherical videos of live events, thus opening new scenarios for cultural heritage enjoyment and dissemination; deep learning approaches both to improve internal processes (e.g., back-office applications for music information retrieval) and to offer advanced services to users (e.g., highly-customized experiences)
On the refractive index for a nonmagnetic two-component medium: resolution of a controversy
The refractive index of a dielectric medium comprising both passive and
inverted components in its permittivity was determined using two methods: (i)
in the time domain, a finite-difference algorithm to compute the
frequency-domain reflectance from reflection data for a pulsed plane wave that
is normally incident on a dielectric half-space, and (ii) in the frequency
domain, the deflection of an obliquely incident Gaussian beam on transmission
through a dielectric slab. The dielectric medium was found to be an active
medium with a negative real part for its refractive index. Thereby, a recent
controversy in the scientific literature was resolved.Comment: manuscript submitted to Optics Communication
A Web-Oriented Multi-layer Model to Interact with Theatrical Performances
This paper presents an innovative approach to online fruition
of theater performances. Web applications like traditional viewers are
already available for the wide audience of Internet users. Our proposal
aims at adding both interactivity and multi-layer fruition, and a way
to manipulate and create new media. The premise to reach these goals
is digitizing a number of heterogeneous materials in order to describe a
single performance comprehensively, e.g. different video and audio-takes
from different perspectives, and a number of related materials such as
scripts, fashion plates, playbills, etc. The format we adopt to encode
such information is based on the XML international standard known
as IEEE 1599. Finally, an advanced Web player supporting search and
play functions for synchronized materials must be designed. This work
describes the whole process, from the acquisition of materials directly on
the stage to their publishing on a Web portal
Optics and Quantum Electronics
Contains reports on nine research projects split into two sections.National Science Foundation (Grant DAR80-08752)National Science Foundation (Grant ECS79-19475)Joint Services Electronics Program (Contract DAAG29-83-K-0003)National Science Foundation (Grant ECS80-20639)National Science Foundation (Grant ECS82-11650
Efficient low-power terahertz generation via on-chip triply-resonant nonlinear frequency mixing
Achieving efficient terahertz (THz) generation using compact turn-key sources
operating at room temperature and modest power levels represents one of the
critical challeges that must be overcome to realize truly practical
applications based on THz. Up to now, the most efficient approaches to THz
generation at room temperature -- relying mainly on optical rectification
schemes -- require intricate phase-matching set-ups and powerful lasers. Here
we show how the unique light-confining properties of triply-resonant photonic
resonators can be tailored to enable dramatic enhancements of the conversion
efficiency of THz generation via nonlinear frequency down-conversion processes.
We predict that this approach can be used to reduce up to three orders of
magnitude the pump powers required to reach quantum-limited conversion
efficiency of THz generation in nonlinear optical material systems.
Furthermore, we propose a realistic design readily accesible experimentally,
both for fabrication and demonstration of optimal THz conversion efficiency at
sub-W power levels
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