Exact real-time dynamics of the quantum Rabi model

We use the analytical solution of the quantum Rabi model to obtain absolutely convergent series expressions of the exact eigenstates and their scalar products with Fock states. This enables us to calculate the numerically exact time evolution of and for all regimes of the coupling strength, without truncation of the Hilbert space. We find a qualitatively different behavior of both observables which can be related to their representations in the invariant parity subspaces.Comment: 8 pages, 7 figures, published versio

Measuring correlated electron dynamics with time-resolved photoemission spectroscopy

Time-resolved photoemission experiments can reveal fascinating quantum dynamics of correlated electrons. However, the thermalization of the electronic system is typically so fast that very short probe pulses are necessary to resolve the time evolution of the quantum state, and this leads to poor energy resolution due to the energy-time uncertainty relation. Although the photoemission intensity can be calculated from the nonequilibrium electronic Green functions, the converse procedure is therefore difficult. We analyze a hypothetical time-resolved photoemission experiment on a correlated electronic system, described by the Falicov-Kimball model in dynamical mean-field theory, which relaxes between metallic and insulating phases. We find that the real-time Green function which describes the transient behavior during the buildup of the metallic state cannot be determined directly from the photoemission signal. On the other hand, the characteristic collapse-and-revival oscillations of an excited Mott insulator can be observed as oscillating weight in the center of the Mott gap in the time-dependent photoemission spectrum.Comment: 12 pages, 5 figure

Transforming the Enterprise of Acquiring Public Sector Complex Systems

Proceedings Paper (for Acquisition Research Program)The acquisition of public sector complex systems is time consuming, very expensive, and rife with uncertainties. The enterprise associated with acquisition is an excellent candidate for transformation''fundamental change to achieve substantially higher levels of value. This paper argues that choosing among alternative transformation initiatives should be based on an enterprise-wide perspective as well as an economic valuation of the alternative investments. An options-based methodology for assessing economic value is presented and illustrated.Naval Postgraduate School Acquisition Research ProgramApproved for public release; distribution is unlimited

Tone-activated, remote, alert communication system

Pocket sized transmitter, frequency modulated by crystal derived tones, with integral loop antenna provides police with easy operating alert signal communicator which uses patrol car radio to relay signal. Communication channels are time shared by several patrol units

Tunneling gap of laterally separated quantum Hall states

We use a method of matched asymptotics to determine the energy gap of two counter-propagating, strongly interacting, quantum Hall edge states. The microscopic edge state dispersion and Coulomb interactions are used to precisely constrain the short-distance behavior of an integrable field theory, which then determines the low energy spectrum. We discuss the relationship of our results to the tunneling measurements of Kang et al., Nature 403, 59 (2000).Comment: 4 pages, 1 figur

LDA+DMFT computation of the electronic spectrum of NiO

The electronic spectrum, energy gap and local magnetic moment of paramagnetic NiO are computed by using the local density approximation plus dynamical mean-field theory (LDA+DMFT). To this end the noninteracting Hamiltonian obtained within the local density approximation (LDA) is expressed in Wannier functions basis, with only the five anti-bonding bands with mainly Ni 3d character taken into account. Complementing it by local Coulomb interactions one arrives at a material-specific many-body Hamiltonian which is solved by DMFT together with quantum Monte-Carlo (QMC) simulations. The large insulating gap in NiO is found to be a result of the strong electronic correlations in the paramagnetic state. In the vicinity of the gap region, the shape of the electronic spectrum calculated in this way is in good agreement with the experimental x-ray-photoemission and bremsstrahlung-isochromat-spectroscopy results of Sawatzky and Allen. The value of the local magnetic moment computed in the paramagnetic phase (PM) agrees well with that measured in the antiferromagnetic (AFM) phase. Our results for the electronic spectrum and the local magnetic moment in the PM phase are in accordance with the experimental finding that AFM long-range order has no significant influence on the electronic structure of NiO.Comment: 15 pages, 6 figures, 1 table; published versio

Hydrogen Sulfide as a Toxic Product in the Small-Large Intestine Axis and its Role in IBD Development

The small-large intestine axis in hydrogen sulfide accumulation and testing of sulfate and lactate in the gut-gut axis of the intestinal environment has not been well described. Sulfate reducing bacteria (SRB) of the Desulfovibrio genus reduce sulfate to hydrogen sulfide and can be involved in ulcerative colitis development. The background of the research was to find correlations between hydrogen sulfide production under the effect of an electron acceptor (sulfate) and donor (lactate) at different concentrations and Desulfovibrio piger Vib-7 growth, as well as their dissimilatory sulfate reduction in the intestinal small-large intestinal environment. METHODS: Microbiological, biochemical, and biophysical methods, and statistical processing of the results (principal component and cross-correlation analyses) were used. RESULTS: D. piger Vib-7 showed increased intensity of bacterial growth and hydrogen sulfide production under the following concentrations of sulfate and lactate: 17.4 mM and 35.6 mM, respectively. The study showed in what kind of intestinal environment D. piger Vib-7 grows at the highest level and produces the highest amount of hydrogen sulfide. CONCLUSIONS: The optimum intestinal environment of D. piger Vib-7 can serve as a good indicator of the occurrence of inflammatory bowel diseases; meaning that these findings can be broadly used in medicine practice dealing with the monitoring and diagnosis of intestinal ailments

Identifying Knowledge, Self-efficacy and Response Efficacy of Alternative Discipline Strategies among Low-income Black, Latino and White Parents

Corporal punishment (CP) leads to detrimental mental and physical consequences for a child. One way to prevent CP is to encourage parents to apply alternative discipline strategies that do not involve violence. Based on the knowledge—behavior gap framework in public health education, this study analyzed the focus group data of 75 low-income Black, Latino and White parents to uncover commonalties and differences in their knowledge, self-efficacy and response efficacy of alternative discipline strategies. Findings revealed that parents knew several alternative discipline strategies and had confidence in their ability to conduct these strategies. However, parents reported that some strategies were hard to implement because they lacked the relevant resources. Moreover, parents did not perceive that alternative discipline strategies were effective without using some forms of CP. Knowledge, self-efficacy and response efficacy of alternative discipline strategies are risk factors for child physical abuse and addressing them will help prevent injury and health impacts on children, while providing safe, stable, nurturing relationships and environments for child development

Examining Sources of Social Norms Supporting Child Corporal Punishment Among Low-Income Black, Latino, and White Parents

Child corporal punishment is a prevalent public health problem in the U.S. Although corporal punishment is sustained through parents’ perceptions of social norms supporting this discipline behavior, little research has investigated where these normative perceptions come from. To fill this gap, we conducted 13 focus groups including 75 low-income Black, Latino, and White parents across five states in the U.S. Results revealed that one influential source of Black and White parents’ perceived norms was their positive framing of corporal punishment experiences during childhood. Furthermore, Black parents formed normative perceptions based on identification with parents in their racial/ethnic group, while White parents did so with parents sharing the same generation. Results are interpreted in light of the false consensus effect and self-categorization theory. In contrast, Latino parents viewed their childhood experience of corporal punishment as negative and distanced their parenting practices from those practiced in their countries of origin, suggesting an influence of acculturation. Their perceived norms were likely transmitted through interpersonal communication within their social networks. These findings shed light on how social norms are formed and in turn guide parents’ use of corporal punishment as a tool to discipline children