Operator Representations of a q-Deformed Heisenberg Algebra

A class of well-behaved *-representations of a q-deformed Heisenberg algebra is studied and classified.Comment: 17 pages; Plain Tex; no figure

Radar Derived Spatial Statistics of Summer Rain

Data reduction and analysis procedures are discussed along with the physical and statistical descriptors used. The statistical modeling techniques are outlined and examples of the derived statistical characterization of rain cells in terms of the several physical descriptors are presented. Recommendations concerning analyses which can be pursued using the data base collected during the experiment are included

Maintaining Quantum Coherence in the Presence of Noise through State Monitoring

Unsharp POVM measurements allow the estimation and tracking of quantum wavefunctions in real-time with minimal disruption of the dynamics. Here we demonstrate that high fidelity state monitoring, and hence quantum control, is possible even in the presence of classical dephasing and amplitude noise, by simulating such measurements on a two-level system undergoing Rabi oscillations. Finite estimation fidelity is found to persist indefinitely long after the decoherence times set by the noise fields in the absence of measurement.Comment: 5 pages, 4 figure

Asymptotic Statistics of Nodal Domains of Quantum Chaotic Billiards in the Semiclassical Limit

Quantum chaos concerns eigenfunctions of the Laplace operator in a domain where a billiard ball would bounce chaotically. Such chaotic eigenfunctions have been conjectured to share statistical properties of their nodal domains with a simple percolation model, from which many interesting quantities can be computed analytically. We numerically test conjectures on the number and size of nodal domains of quantum chaotic eigenfunctions at very high energies, approaching the semiclassical limit. We use a highly efficient scaling method to quickly compute eigenfunctions at low resolution and interpolate to higher resolution. We computed 10^5 eigenfunctions and counted 10^9 nodal domains. Our results agree with the conjectured size nodal domains but disagree with the conjectured mean and variance of the number of nodal domains

Harmonic generation in nonlinear beam-plasma systems

Harmonic generation and components of nonlinear cylindrical beam plasma devices including RF energy couplin

Production of heralded pure single photons from imperfect sources using cross phase modulation

Realistic single-photon sources do not generate single photons with certainty. Instead they produce statistical mixtures of photons in Fock states $\ket{1}$ and vacuum (noise). We describe how to eliminate the noise in the output of the sources by means of another noisy source or a coherent state and cross phase modulation (XPM). We present a scheme which announces the production of pure single photons and thus eliminates the vacuum contribution. This is done by verifying a XPM related phase shift with a Mach-Zehnder interferometer.Comment: 8 pages, 8 EPS figures, RevTeX4. Following changes have been made in v.3: Title and abstract slightly changed; numerous minor revisions and clarifications within the text; an appendix with three new figures has been added. In version v4 we have included a supplementary analysis of our scheme that takes into account absorption losses. Our analysis is heuristic and based on a phenomenological model, which is independent of the physical realization of the proposed scheme. We have estimated upper bounds up to which absorption losses can be tolerated, so as our scheme to improve the efficiency of single photon sources still works. Accepted for publication in Phys. Rev.