Equivalence between squeezed-state and twin-beam communication channels

We show the equivalence between two different communication schemes that employ a couple of modes of the electromagnetic field. One scheme uses unconventional heterodyne detection, with correlated signal and image-band modes in a twin-beam state from parametric downconversion. The other scheme is realized through a complex-number coding over quadrature-squeezed states of two uncorrelated modes, each detected by ordinary homodyning. This equivalence concerns all the stages of the communication channel: the encoded state, the optimal amplifier for the channel, the master equation modeling the loss, and the output measurement scheme. The unitary transformation that connects the two communication schemes is realized by a frequency conversion device.Comment: 15 pages. Two latex figures included. To appear on Modern Phys. Lett.

The Digital Age: Reminder and Confirmation Preference in Blood Donation

Introduction: It is widely accepted that individuals are more likely to comply and follow through with responsibilities when reminded and asked to confirm their commitments. With the American Red Cross’ access to fast and affordable communication and this notion in mind, there is potential to develop new recruitment strategies and better methods of ensuring blood donation commitments. In particular, understanding modes of communication with the donor population can have significant implications: avoiding loss of follow up, improving donor experience, and ensuring appropriate use of resources and staff; therefore, the American Red Cross is interested in understanding demographic differences among those who prefer different modes of communication for blood donor appointment reminders and confirmations.https://scholarworks.uvm.edu/comphp_gallery/1223/thumbnail.jp

On the existence of internal modes of sine-Gordon kinks

We study whether or not sine-Gordon kinks exhibit internal modes or ``quasimodes.'' By considering the response of the kinks to ac forces and initial distortions, we show that neither intrinsic internal modes nor ``quasimodes'' exist in contrast to previous reports. However, we do identify a different kind of internal mode bifurcating from the bottom edge of the phonon band which arises from the discretization of the system in the numerical simulations, thus confirming recent predictions.Comment: 4 pages, 2 figures, REVTeX, to appear as a Rapid Communication in Phys Rev E (July 1st

Super- and Anti-Principal Modes in Multi-Mode Waveguides

We introduce a new type of states for light in multimode waveguides featuring strongly enhanced or reduced spectral correlations. Based on the experimentally measured multi-spectral transmission matrix of a multimode fiber, we generate a set of states that outperform the established "principal modes" in terms of the spectral stability of their output spatial field profiles. Inverting this concept also allows us to create states with a minimal spectral correlation width, whose output profiles are considerably more sensitive to a frequency change than typical input wavefronts. The resulting "super-" and "anti-principal" modes are made orthogonal to each other even in the presence of mode-dependent loss. By decomposing them in the principal mode basis, we show that the super-principal modes are formed via interference of principal modes with closeby delay times, whereas the anti-principal modes are a superposition of principal modes with the most different delay times available in the fiber. Such novel states are expected to have broad applications in fiber communication, imaging, and spectroscopy.Comment: 8 pages, 5 figures, plus supplementary materia