What is Surrealistic about Bohm Trajectories?

We discuss interferometers in Bohmian quantum mechanics. It is shown that, with the correct configuration space, Bohm trajectories in a which way interferometer are not surrealistic, but behaves exactly as common sense suggests. Some remarks about a way to generalize Bohmian mechanics to treat density matrix are also made. PACS: 03.65.Bz, 03.75.Dg Key words: Bohm Trajectories, Which Way Interferometers, ESSWComment: 9 pages, 4 figures, Submitted to Phys. Lett.

Towards the understanding of Decoherence on Ion Traps

Two mechanisms of decoherence in ion traps are studied, specially related to the experiment [Kielpinski et al., Science 291 (2001) 1013]. Statistical hypothesis are made about the unknown variables and the expected behaviour of the visibility of the best experimental pattern is calculated for each mechanism. Data from the experiment are analyzed and show to be insufficient to distinguish between them. We suggest improvements which can do this with slight modifications in the present facilities.Comment: 7 pages, 4 figures, submitted to Phys Lett

Low lying magnetic states of the mixed valence cobalt ludwigite

There are two interpretations offered for the different structural and magnetic properties of the mixed valence homo-metallic ludwigites, Co3O2BO3 and Fe3O2BO3. One of them associates the physical behavior to charge ordering processes among the cations, as is well known in simpler oxides. The other attributes the effects to local pairwise magnetic interactions. Recently first principles calculations in the iron ludwigite have shown that the structural cation dimerization is due to the formation of strong magnetic dyads supporting the second model. Here we confirm the dominance of magnetic interactions to explain the absence of dimerization in the cobalt compound. Density functional non-collinear spin calculations are carried out on Co3O2BO3 to determine its low temperature magnetic order. Low spin is found on tri-valent cobalt sites, thus preventing the formation of the ferromagnetic dyad, the mechanism which favors dimerization in Fe3O2BO3. We conclude that the difference between high spin Fe3+ and low spin Co3+ pairwise interactions is responsible for the observed differences between the two compounds. The pairwise magnetic interactions also explain the difference between the existence of low temperature bulk AF state in the Fe ludwigite and its absence in the Co material.Comment: 17 pages, 2 Tables, 3 Figure

Quasiprobability and Probability Distributions for Spin 1/2 States

We develop a Radon like transformation, in which $P$ quasiprobability distribution for spin 1/2 states is written in terms the tomographic probability distribution $w$.Comment: 14 pages, accepted by Found. Phys. Let

Realistic Decoherence Free Subspaces

Decoherence free subspaces (DFS) is a theoretical tool towards experimental implementation of quantum information storage and processing. However, they represent an experimental challenge, since conditions for their existence are very stringent. This work explores the situation in which a system of $N$ oscillators coupled to a bath of harmonic oscillators is close to satisfy the conditions for the existence of DFS. We show, in the Born-Markov limit and for small deviations from separability and degeneracy conditions, that there are {\emph{weak decoherence subspaces}} which resemble the original notion of DFS.Comment: 9 pages, no figures, submitted to Phys. Rev. A. This is a completelly rewritten and expanded version of quant-ph/020203

A non-violent protest : giving people the tools to know where to buy diamonds and where their diamonds are coming from : an honors thesis (HONRS 499)

I have had enough. People are not being told about conflict diamonds, and as a result, they are unknowingly supporting violent conflict in Africa. I want to call attention to our government's failure to enforce its own laws concerning diamond sales and the failure of large retailers to follow the Kimberly Process. I decided to educate the public on Saturday April 12th by means of a non-violent protest. A small group of Ball State students, professors, and myself will arrive at the Muncie Walmart at 10am to pass out leaflets and peaceably discuss these issues with the public. The group will move on to the Muncie Target at 3pm. If we are asked to leave Walmart early, we will then proceed directly to Target.I will be presenting my findings during Final's Week (at Motinis). I will show the documentary that inspired mywork (Blood on the Stone), reflect on the protest, and provide the audience with information on both conflict diamonds and how to be a smart buyer. I have also launched a website to provide those interested with links to more detailed information and organizations with which they can get involved. Here is the address: http:l/tmmackintosh.iweb.bsu.edu/conflictdiamonds. Thank you for taking the time to look at it.Honors CollegeThesis (B.?.

Optimal Guaranteed Cost Control of Discrete-Time Linear Systems subject to Structured Uncertainties

In this paper, we propose state- and static output-feedback generalized guaranteed cost control (GCC) approaches for discrete-time linear systems subject to norm-bounded structured parametric uncertainties. This method enables the convex synthesis for a more general class of systems, where uncertainties are uncorrelated block diagonal, and no feed-through uncertainty is multiplicative with control input ones. It also provides necessary and sufficient conditions for state-feedback and sufficient conditions for static output-feedback. We also present a comparative study among the proposed controllers, standard Linear Quadratic Regulator, and Guaranteed Cost Controller found in the literature.Comment: Published at International Journal of Contro

Entanglement in single particle systems

We address some of the most commonly raised questions about entanglement, especially with regard to so-called occupation number entanglement. To answer unambiguously whether entanglement can exist in a one-atom delocalized state, we propose an experiment capable of showing violations of Bell's inequality using only this state and local operations. As a byproduct, this experiment suggests a means of creating an entangled state of two different chemical species. By comparison with a massless system, we argue that there should be no fundamental objection to such a superposition and its creation may be within reach of present technology.Comment: 6 pages, 1 figur

Guaranteed Cost Approach to Robust Model Predictive Control of Uncertain Linear Systems

In this paper we propose a constrained guaranteed cost robust model predictive controller (GCMPC) for uncertain discrete time systems. This controller was developed based on a quadratic cost functional and guarantee robustness with respect to quadratically bound uncertainties. Such a class of problems is currently intractable by Min-Max Robust Model Predictive Controllers without polytopic approximations of the uncertainties. The proposed technique is computationally more efficient then an enumeration-based approach and requires only a Quadratically Constrained Quadratic Problem (QCQP) optimization, whereas LMI-based GCMPC approaches require a Semi-Definite Programming (SDP) optimization.Comment: Accepted to 2017 IEEE American Control Conferenc

Safely Optimizing Highway Traffic with Robust Model Predictive Control-based Cooperative Adaptive Cruise Control

Road traffic crashes have been the leading cause of death among young people. Most of these accidents occur when the driver becomes distracted due to fatigue or external factors. Vehicle platooning systems such as Cooperative Adaptive Cruise Control (CACC) are one of the results of the effort devoted to the development of technologies for decreasing the number of road crashes and fatalities. Previous studies have suggested such systems improve up to 273\% highway traffic throughput and fuel consumption in more than 15\% if the clearance between vehicles in this class of roads can be reduced to 2 meters. This paper proposes an approach that guarantees a minimum safety distance between vehicles taking into account the overall system delays and braking capacity of each vehicle. A $l\infty$-norm Robust Model Predictive Controller (RMPC) is developed to guarantee the minimum safety distance is not violated due to uncertainties on the lead vehicle behavior. A formulation for a lower bound clearance of vehicles inside a platoon is also proposed. Simulation results show the performance of the proposed approach compared to a nominal controller when the system is subject to both modeled and unmodeled disturbances.Comment: Submitted to Transactions on Intelligent Transportation System