54 research outputs found
Temporal modes in quantum optics: then and now
We review the concepts of temporal modes (TMs) in quantum optics, highlighting Roy Glauber's crucial and historic contributions to their development, and their growing importance in quantum information science. TMs are orthogonal sets of wave packets that can be used to represent a multimode light field. They are temporal counterparts to transverse spatial modes of light and play analogous roles - decomposing multimode light into the most natural basis for isolating statistically independent degrees of freedom. We discuss how TMs were developed to describe compactly various processes: superfluorescence, stimulated Raman scattering, spontaneous parametric down conversion, and spontaneous four-wave mixing. TMs can be manipulated, converted, demultiplexed, and detected using nonlinear optical processes such as three-wave mixing and quantum optical memories. As such, they play an increasingly important role in constructing quantum information networks
Subsurface Defect Detection in Ceramic Materials Using Optical Gating Techniques
Components made from advanced ceramics materials, because of their thermomechanical and chemical properties, have several advantages over traditional steel parts, making them well suited for use in severe operating environments. In particular, silicon nitride (Si3N4) ceramics, because of their stiffness and resistance to corrosion, are being considered for use in rolling contact elements such as bearings and contact races. In addition, when combined with rare-earth oxide sintering aids such as yttria (Y2O3), silicon nitride ceramics have high-temperature strength which makes them excellent candidates for components such as rotors and blades in advanced turbine engines
Long-distance quantum communication with atomic ensembles and linear optics
Quantum communication holds a promise for absolutely secure transmission of
secret messages and faithful transfer of unknown quantum states. Photonic
channels appear to be very attractive for physical implementation of quantum
communication. However, due to losses and decoherence in the channel, the
communication fidelity decreases exponentially with the channel length. We
describe a scheme that allows to implement robust quantum communication over
long lossy channels. The scheme involves laser manipulation of atomic
ensembles, beam splitters, and single-photon detectors with moderate
efficiencies, and therefore well fits the status of the current experimental
technology. We show that the communication efficiency scale polynomially with
the channel length thereby facilitating scalability to very long distances.Comment: 2 tex files (Main text + Supplement), 4 figure
Experimental simulation of quantum tunneling in small systems
It is well known that quantum computers are superior to classical computers
in efficiently simulating quantum systems. Here we report the first
experimental simulation of quantum tunneling through potential barriers, a
widespread phenomenon of a unique quantum nature, via NMR techniques. Our
experiment is based on a digital particle simulation algorithm and requires
very few spin-1/2 nuclei without the need of ancillary qubits. The occurrence
of quantum tunneling through a barrier, together with the oscillation of the
state in potential wells, are clearly observed through the experimental
results. This experiment has clearly demonstrated the possibility to observe
and study profound physical phenomena within even the reach of small quantum
computers.Comment: 17 pages and 8 figure
The Quantum Internet
Quantum networks offer a unifying set of opportunities and challenges across
exciting intellectual and technical frontiers, including for quantum
computation, communication, and metrology. The realization of quantum networks
composed of many nodes and channels requires new scientific capabilities for
the generation and characterization of quantum coherence and entanglement.
Fundamental to this endeavor are quantum interconnects that convert quantum
states from one physical system to those of another in a reversible fashion.
Such quantum connectivity for networks can be achieved by optical interactions
of single photons and atoms, thereby enabling entanglement distribution and
quantum teleportation between nodes.Comment: 15 pages, 6 figures Higher resolution versions of the figures can be
downloaded from the following link:
http://www.its.caltech.edu/~hjkimble/QNet-figures-high-resolutio
Observation of moving wave packets reveals their quantum state
We show how to infer the quantum state of a wave packet from position probability distributions measured during the packet's motion in an arbitrary potential. We assume a nonrelativistic one-dimensional or radial wave packet. Temporal Fourier transformation and spatial sampling with respect to a newly found set of functions project the density-matrix elements out of the probability distributions. The sampling functions are derivatives of products of regular and irregular wave functions. We note that the ability to infer quantum states in this way depends on the structure of the Schrodinger equation.</p
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