2,636 research outputs found
Decoherence of quantum wavepackets due to interaction with conformal spacetime fluctuations
One of the biggest problems faced by those attempting to combine quantum
theory and general relativity is the experimental inaccessibility of the
unification scale. In this paper we show how incoherent conformal waves in the
gravitational field, which may be produced by quantum mechanical zero-point
fluctuations, interact with the wavepackets of massive particles. The result of
this interaction is to produce decoherence within the wavepackets which could
be accessible in experiments at the atomic scale.
Using a simple model for the coherence properties of the gravitational field
we derive an equation for the evolution of the density matrix of such a
wavepacket. Following the primary state diffusion programme, the most promising
source of spacetime fluctuations for detection are the above zero-point energy
fluctuations. According to our model, the absence of intrinsic irremoveable
decoherence in matter interferometry experiments puts bounds on some of the
parameters of quantum gravity theories. Current experiments give \lambda > 18.
, where \lambda t_{Planck} is an effective cut-off for the validity of
low-energy quantum gravity theories.Comment: REVTeX forma
From Heisenberg matrix mechanics to EBK quantization: theory and first applications
Despite the seminal connection between classical multiply-periodic motion and
Heisenberg matrix mechanics and the massive amount of work done on the
associated problem of semiclassical (EBK) quantization of bound states, we show
that there are, nevertheless, a number of previously unexploited aspects of
this relationship that bear on the quantum-classical correspondence. In
particular, we emphasize a quantum variational principle that implies the
classical variational principle for invariant tori. We also expose the more
indirect connection between commutation relations and quantization of action
variables. With the help of several standard models with one or two degrees of
freedom, we then illustrate how the methods of Heisenberg matrix mechanics
described in this paper may be used to obtain quantum solutions with a modest
increase in effort compared to semiclassical calculations. We also describe and
apply a method for obtaining leading quantum corrections to EBK results.
Finally, we suggest several new or modified applications of EBK quantization.Comment: 37 pages including 3 poscript figures, submitted to Phys. Rev.
The effectiveness of implementation in Indigenous Australian healthcare: An overview of literature reviews
© 2016 McCalman et al. Background: Effective implementation can maximise the beneficial impacts of health services. It is therefore important to review implementation in the context of Indigenous populations, who suffer some of the greatest disadvantage within developed countries. This paper analyses Aboriginal and Torres Strait Islander (hereafter Indigenous) Australian health implementation reviews to examine the research question: What is the effectiveness of implementation, as reported in the Indigenous Australian health implementation literature? Methods: Eight databases were systematically searched to find reviews of Indigenous Australian health services and/or programs where implementation was the focus. Search terms included AboriginâOR IndigenâOR Torres AND health AND service OR programâOR intervention AND implementation (or like terms) AND Australia AND review. Review findings were analysed through the lens of the PARiHS framework which theorises that successful implementation occurs through the interplay of evidence, context and facilitation. The review followed Cochrane methods but was not registered. Results: Six reviews were found; these encompassed 107 studies that considered health service/program implementation. Included studies described many health services implemented across Australia as not underpinned by rigorous impact evaluation; nevertheless implementers tended to prefer evidence-based interventions. Effective implementation was supported by clearly defined management systems, employment of Indigenous health workers as leaders, community control, partnerships, tailoring for diverse places and settings; and active facilitation methods. Short-term funding meant most studies focused on implementation in one site through pilot initiatives. Only two mentioned cost effectiveness. Indigenous Australian studies incorporated two elements not included in the PARiHS reference guide: the value of community control and equity of service provision across sites. Conclusions: Comparison of the Indigenous Australian review findings against the PARiHS reference guide elements suggested a fledgling but growing state of Indigenous implementation research, and considerable scope to improve the effectiveness of implementation. Further research is required to explore Indigenous people's understandings of what is important in healthcare implementation; particularly in relation to the value of community control and equity issues
Continuous stochastic Schrodinger equations and localization
The set of continuous norm-preserving stochastic Schrodinger equations
associated with the Lindblad master equation is introduced. This set is used to
describe the localization properties of the state vector toward eigenstates of
the environment operator. Particular focus is placed on determining the
stochastic equation which exhibits the highest rate of localization for wide
open systems. An equation having such a property is proposed in the case of a
single non-hermitian environment operator. This result is relevant to numerical
simulations of quantum trajectories where localization properties are used to
reduce the number of basis states needed to represent the system state, and
thereby increase the speed of calculation.Comment: 18 pages in LaTeX + 6 figures (postscript), uses ioplppt.sty. To
appear in J. Phys.
Emergence of classical behavior from the quantum spin
Classical Hamiltonian system of a point moving on a sphere of fixed radius is
shown to emerge from the constrained evolution of quantum spin. The constrained
quantum evolution corresponds to an appropriate coarse-graining of the quantum
states into equivalence classes, and forces the equivalence classes to evolve
as single units representing the classical states. The coarse-grained quantum
spin with the constrained evolution in the limit of the large spin becomes
indistinguishable from the classical system
Remarks on a Proposed Super-Kamiokande Test for Quantum Gravity Induced Decoherence Effects
Lisi, Marrone, and Montanino have recently proposed a test for quantum
gravity induced decoherence effects in neutrino oscillations observed at
Super-Kamiokande. We comment here that their equations have the same
qualitative form as the energy conserving objective state vector reduction
equations discussed by a number of authors. However, using the Planckian
parameter value proposed to explain state vector reduction leads to a neutrino
oscillation effect many orders of magnitude smaller than would be detectable at
Super-Kamiokande. Similar estimates hold for the Ghirardi, Rimini, and Weber
spontaneous localization approach to state vector reduction, and our remarks
are relevant as well to proposed meson and meson tests of gravity
induced decoherence.Comment: 10 pages, plain Tex, no figure
Could health information systems enhance the quality of Aboriginal health promotion? A retrospective audit of Aboriginal health programs in the Northern Territory of Australia.
BACKGROUND:In Australia, health services are seeking innovative ways to utilize data stored in health information systems to report on, and improve, health care quality and health system performance for Aboriginal Australians. However, there is little research about the use of health information systems in the context of Aboriginal health promotion. In 2008, the Northern Territory's publicly funded healthcare system introduced the quality improvement program planning system (QIPPS) as the centralized online system for recording information about health promotion programs. The purpose of this study was to explore the potential for utilizing data stored in QIPPS to report on quality of Aboriginal health promotion, using chronic disease prevention programs as exemplars. We identify the potential benefits and limitations of health information systems for enhancing Aboriginal health promotion. METHODS:A retrospective audit was undertaken on a sample of health promotion projects delivered between 2013 and 2016. A validated, paper-based audit tool was used to extract information stored in the QIPPS online system and report on Aboriginal health promotion quality. Simple frequency counts were calculated for dichotomous and categorical items. Text was extracted and thematically analyzed to describe community participation processes and strategies used in Aboriginal health promotion. RESULTS:39 Aboriginal health promotion projects were included in the analysis. 34/39 projects recorded information pertaining to the health promotion planning phases, such as statements of project goals, 'needs assessment' findings, and processes for consulting Aboriginal people in the community. Evaluation findings were reported in approximately one third of projects and mostly limited to a recording of numbers of participants. For almost half of the projects analyzed, community participation strategies were not recorded. CONCLUSION:This is the first Australian study to shed light on the feasibility of utilizing data stored in a purposefully designed health promotion information system. Data availability and quality were limiting factors for reporting on Aboriginal health promotion quality. Based on our learnings of QIPPS, strategies to improve the quality and accuracy of data entry together with the use of quality improvement approaches are needed to reap the potential benefits of future health promotion information systems
Non-Markovian Quantum Trajectories Versus Master Equations: Finite Temperature Heat Bath
The interrelationship between the non-Markovian stochastic Schr\"odinger
equations and the corresponding non-Markovian master equations is investigated
in the finite temperature regimes. We show that the general finite temperature
non-Markovian trajectories can be used to derive the corresponding
non-Markovian master equations. A simple, yet important solvable example is the
well-known damped harmonic oscillator model in which a harmonic oscillator is
coupled to a finite temperature reservoir in the rotating wave approximation.
The exact convolutionless master equation for the damped harmonic oscillator is
obtained by averaging the quantum trajectories relying upon no assumption of
coupling strength or time scale. The master equation derived in this way
automatically preserves the positivity, Hermiticity and unity.Comment: 19 pages, typos corrected, references adde
Space-like Separation in a Bell Test assuming Gravitationally Induced Collapses
We report on a Bell experiment with space-like separation assuming that the
measurement time is related to gravity-induced state reduction. Two energy-time
entangled photons are sent through optical fibers and directed into unbalanced
interferometers at two receiving stations separated by 18 km. At each station,
the detection of a photon triggers the displacement of a macroscopic mass. The
timing ensures space-like separation from the moment a photon enters its
interferometer until the mass has moved. 2-photon interference fringes with a
visibility of up to 90.5% are obtained, leading to a violation of Bell
inequality
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