A General Theory of Phase-Space Quasiprobability Distributions

We present a general theory of quasiprobability distributions on phase spaces of quantum systems whose dynamical symmetry groups are (finite-dimensional) Lie groups. The family of distributions on a phase space is postulated to satisfy the Stratonovich-Weyl correspondence with a generalized traciality condition. The corresponding family of the Stratonovich-Weyl kernels is constructed explicitly. In the presented theory we use the concept of the generalized coherent states, that brings physical insight into the mathematical formalism.Comment: REVTeX, 4 pages. More information on http://www.technion.ac.il/~brif/science.htm

Phase-space formulation of quantum mechanics and quantum state reconstruction for physical systems with Lie-group symmetries

We present a detailed discussion of a general theory of phase-space distributions, introduced recently by the authors [J. Phys. A {\bf 31}, L9 (1998)]. This theory provides a unified phase-space formulation of quantum mechanics for physical systems possessing Lie-group symmetries. The concept of generalized coherent states and the method of harmonic analysis are used to construct explicitly a family of phase-space functions which are postulated to satisfy the Stratonovich-Weyl correspondence with a generalized traciality condition. The symbol calculus for the phase-space functions is given by means of the generalized twisted product. The phase-space formalism is used to study the problem of the reconstruction of quantum states. In particular, we consider the reconstruction method based on measurements of displaced projectors, which comprises a number of recently proposed quantum-optical schemes and is also related to the standard methods of signal processing. A general group-theoretic description of this method is developed using the technique of harmonic expansions on the phase space.Comment: REVTeX, 18 pages, no figure

Cavity-QED tests of representations of canonical commutation relations employed in field quantization

Various aspects of dissipative and nondissipative decoherence of Rabi oscillations are discussed in the context of field quantization in alternative representations of CCR. Theory is confronted with experiment, and a possibility of more conclusive tests is analyzed.Comment: Discussion of dissipative and nondissipative decoherence is included. Theory is now consistent with the existing data and predictions for new experiments are more reliabl

Source monitoring deficits in patients with schizophrenia; a multinomial modelling analysis

Background. Schizophrenia patients, particularly those with symptoms such as thought insertion, passivity experiences and hallucinations, may share an underlying cognitive deficit in monitoring the generation of their own thoughts. This deficit, which has been referred to as ‘autonoetic agnosia’, may result in the conclusion that self-generated thoughts come from an external source. Previous work supports this notion, yet the statistical approaches that have been used have not enabled a distinction between specific deficits suggesting autonoetic agnosia and more general cognitive dysfunction. Methods. Autonoetic agnosia was assessed using source-monitoring paradigms in 28 patients with schizophrenia and 19 control subjects. Multinomial model analyses, which allow the distinction between deficits in recognizing information, remembering its source, and response biases, were applied to the data. Results. Schizophrenia patients were impaired in discriminating between words that came from two external sources, from two internal sources, and one internal and one external source. In a condition requiring subjects to distinguish between words they had heard from those they had imagined hearing, when schizophrenic patients did not remember the source of the information, they showed a stronger bias than controls to report that it had come from an external source. Conclusions. The application of multinomial models to source monitoring data suggests that schizophrenia patients have source monitoring deficits that are not limited to the distinction between internally-generated and externally-perceived information. However, when schizophrenia patients do not remember the source of information, they may be more likely than controls to report that it came from an external source

Source monitoring deficits in patients with schizophrenia; a multinomial modelling analysis

Background. Schizophrenia patients, particularly those with symptoms such as thought insertion, passivity experiences and hallucinations, may share an underlying cognitive deficit in monitoring the generation of their own thoughts. This deficit, which has been referred to as ‘autonoetic agnosia’, may result in the conclusion that self-generated thoughts come from an external source. Previous work supports this notion, yet the statistical approaches that have been used have not enabled a distinction between specific deficits suggesting autonoetic agnosia and more general cognitive dysfunction. Methods. Autonoetic agnosia was assessed using source-monitoring paradigms in 28 patients with schizophrenia and 19 control subjects. Multinomial model analyses, which allow the distinction between deficits in recognizing information, remembering its source, and response biases, were applied to the data. Results. Schizophrenia patients were impaired in discriminating between words that came from two external sources, from two internal sources, and one internal and one external source. In a condition requiring subjects to distinguish between words they had heard from those they had imagined hearing, when schizophrenic patients did not remember the source of the information, they showed a stronger bias than controls to report that it had come from an external source. Conclusions. The application of multinomial models to source monitoring data suggests that schizophrenia patients have source monitoring deficits that are not limited to the distinction between internally-generated and externally-perceived information. However, when schizophrenia patients do not remember the source of information, they may be more likely than controls to report that it came from an external source

Health plan decision making with new medicare information materials.

OBJECTIVE: To examine the effect of providing new Medicare information materials on consumers' attitudes and behavior about health plan choice. DATA SOURCE: New and experienced Medicare beneficiaries who resided in the Kansas City metropolitan statistical area during winter 1998-99 were surveyed. More than 2,000 computer-assisted telephone interviews were completed across the two beneficiary populations with a mean response rate of 60 percent. STUDY DESIGN: Medicare beneficiaries were randomly assigned to a control group or one of three treatment groups that received varying amounts and types of new Medicare information materials. One treatment group received the Health Care Financing Administrations's pilot Medicare & You 1999 handbook, a second group received the same version of the handbook and a Medicare version of the Consumer Assessment of Health Plans (CAHPS) report, and a third treatment group received the Medicare & You bulletin, an abbreviated version of the handbook. PRINCIPAL FINDINGS: Results of the study suggest that the federal government's new consumer information materials are having some influence on Medicare beneficiaries' attitudes and behaviors about health plan decision making. Experienced beneficiary treatment group members were significantly more confident with their current health plan choice than control group members, but new beneficiaries were significantly less likely to use the new materials to choose or change health plans than control group members. In general the effects on confidence and health plan switching did not vary across the different treatment materials. CONCLUSIONS: The 1999 version of the Medicare & You materials contained a message that it is not necessary to change health plans. This message appears to have decreased the likelihood of using the new materials to choose or change plans, whereas other materials to which beneficiaries are exposed may encourage plan switching. Because providing more information to beneficiaries did not result in commensurate increases in confidence levels or rate of health plan switching, factors other than the amount of information, such as how the information is presented, may be more critical than volume

Wissensaufbau und Handlungsbewertung bei oekologischen Problemen Abschlussbericht

UuStB Koeln=38*-890107228 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman