Quantum retrodiction in open systems

Quantum retrodiction involves finding the probabilities for various preparation events given a measurement event. This theory has been studied for some time but mainly as an interesting concept associated with time asymmetry in quantum mechanics. Recent interest in quantum communications and cryptography, however, has provided retrodiction with a potential practical application. For this purpose quantum retrodiction in open systems should be more relevant than in closed systems isolated from the environment. In this paper we study retrodiction in open systems and develop a general master equation for the backward time evolution of the measured state, which can be used for calculating preparation probabilities. We solve the master equation, by way of example, for the driven two-level atom coupled to the electromagnetic field.Comment: 12 pages, no figure

Emergency Preparedness Among Salem’s Hispanic Population: Proposal to Improve Emergency Preparedness and Engagement

The emergency preparedness of the residents of the City of Salem is of great importance to the City and the resilience of the community. The City’s emergency management mission states “to ensure that the City is prepared for a disaster by ensuring coordination of protection, prevention, mitigation, response, and recovery activities that increase the City’s capabilities to minimize loss of life and reduce impacts from disasters” (City of Salem, 2014). Oregon and the City of Salem are susceptible to a variety of emergencies and disasters. These disasters are infrequent compared to other areas of the country that face a recurring threat of hurricanes, tornados, severe winter storms or other events and may lead to complacency. Due to the infrequency of disasters, it is even more important that emergency preparedness efforts engage the population and maintain preparedness efforts to ensure that the community is prepared for an eventual disaster. The Hispanic population of Salem accounts for more than one fifth of the total population (US Census Bureau, 2017) and needs to be an integral part of emergency preparedness efforts. Hispanics require an emergency preparedness approach that addresses the diversity of this population group, barriers to emergency preparedness and communication challenges. Emergency preparedness education, outreach and communication with the Hispanic population have not been fully addressed

Retrodictive states and two-photon quantum imaging

We use retrodictive quantum theory to analyse two-photon quantum imaging systems. The formalism is particularly suitable for calculating conditional probability distributions.Comment: 5 pages, 3 figure

Measurement master equation

We derive a master equation describing the evolution of a quantum system subjected to a sequence of observations. These measurements occur randomly at a given rate and can be of a very general form. As an example, we analyse the effects of these measurements on the evolution of a two-level atom driven by an electromagnetic field. For the associated quantum trajectories we find Rabi oscillations, Zeno-effect type behaviour and random telegraph evolution spawned by mini quantum jumps as we change the rates and strengths of measurement.Comment: 14 pages and 8 figures, Optics Communications in pres