8 research outputs found
Noncommutative Quantum Mechanics and rotating frames
We study the effect of noncommutativity of space on the physics of a quantum
interferometer located in a rotating disk in a gauge field background. To this
end, we develop a path-integral approach which allows defining an effective
action from which relevant physical quantities can be computed as in the usual
commutative case. For the specific case of a constant magnetic field, we are
able to compute, exactly, the noncommutative Lagrangian and the associated
shift on the interference pattern for any value of .Comment: 17 pages, presentation improved, references added. To appear in
Physical Review
Noncommutative Quantum Mechanics and Seiberg-Witten Map
In order to overcome ambiguity problem on identification of mathematical
objects in noncommutative theory with physical observables, quantum mechanical
system coupled to the NC U(1) gauge field in the noncommutative space is
reformulated by making use of the unitarized Seiberg-Witten map, and applied to
the Aharonov-Bohm and Hall effects of the NC U(1) gauge field. Retaining terms
only up to linear order in the NC parameter \theta, we find that the AB
topological phase and the Hall conductivity have both the same formulas as
those of the ordinary commutative space with no \theta-dependence.Comment: 7 pages, no figures, uses revtex4; 8 pages, conclusion changed,
Appendix adde
Noncommutative quantum mechanics and Bohm's ontological interpretation
We carry out an investigation into the possibility of developing a Bohmian
interpretation based on the continuous motion of point particles for
noncommutative quantum mechanics. The conditions for such an interpretation to
be consistent are determined, and the implications of its adoption for
noncommutativity are discussed. A Bohmian analysis of the noncommutative
harmonic oscillator is carried out in detail. By studying the particle motion
in the oscillator orbits, we show that small-scale physics can have influence
at large scales, something similar to the IR-UV mixing
Phenomenology of Particle Production and Propagation in String-Motivated Canonical Noncommutative Spacetime
We outline a phenomenological programme for the search of effects induced by
(string-motivated) canonical noncommutative spacetime. The tests we propose are
based, in analogy with a corresponding programme developed over the last few
years for the study of Lie-algebra noncommutative spacetimes, on the role of
the noncommutativity parameters in the dispersion relation. We focus on
the role of deformed dispersion relations in particle-production collision
processes, where the noncommutativity parameters would affect the threshold
equation, and in the dispersion of gamma rays observed from distant
astrophysical sources. We emphasize that the studies here proposed have the
advantage of involving particles of relatively high energies, and may therefore
be less sensitive to "contamination" (through IR/UV mixing) from the UV sector
of the theory. We also explore the possibility that the relevant deformation of
the dispersion relations could be responsible for the experimentally-observed
violations of the GZK cutoff for cosmic rays and could have a role in the
observation of hard photons from distant astrophysical sources.Comment: With respect to the experimental information available at the time of
writing version 1 of this manuscript (hep-th/0109191v1) the situation has
evolved significantly. Our remarks on the benefits of high-energy
observations found additional encouragement from the results reported in
hep-th/020925
Quantum Gravity, Field Theory and Signatures of Noncommutative Spacetime
A pedagogical introduction to some of the main ideas and results of field
theories on quantized spacetimes is presented, with emphasis on what such field
theories may teach us about the problem of quantizing gravity. We examine to
what extent noncommutative gauge theories may be regarded as gauge theories of
gravity. UV/IR mixing is explained in detail and we describe its relations to
renormalization, to gravitational dynamics, and to deformed dispersion
relations in models of quantum spacetime of interest in string theory and in
doubly special relativity. We also discuss some potential experimental probes
of spacetime noncommutativity.Comment: 26 pages, 4 figures; v2: comments and references added; v3: typos
corrected, clarifying comments and references added; Based on Plenary Lecture
delivered at the XXIX Encontro Nacional de Fisica de Particulas e Campos, Sao
Lourenco, Brasil, September 22-26, 2008; Final version to be published in
General Relativity and Gravitatio
Exploring Cumulative Disadvantage, Telomere Length, and Breast Cancer among Black and White Women
Objectives: Cumulative disadvantage (CD) is a concept that recognizes the influence of social determinants on health over the lifecourse—emphasizing accumulated stressors as contributors to physiological damage. The shortening of telomeres has been found to have a direct relationship with increased cancer incidence and overall health. The purpose of this research is to develop a triangulated and biologically validated CD instrument to explore breast cancer disparities among Black and White women.
Methods: We recruited a purposeful sample of 15 White and 15 Black pre-menopausal women (ages 25–50 years) who had donated normal tissue to the Susan G. Komen Tissue Bank. Semi-structured qualitative interviews, designed to investigate participants’ exposure to lifetime stressors, were conducted. Drawing from the qualitative interviews and previous research, a quantitative survey instrument was developed to capture the range of stressors experienced by our sample of women. All respondents completed the quantitative survey and their telomere length was assessed using DNA extracted from peripheral blood leukocytes.
Results: Qualitative and quantitative assessments of CD were consistent across childhood, adult, and lifetime stressors. Black respondents reported more childhood stressors (t=-2.28, p=0.03), adult stressors (t=-1.87, p=0.07), and lifetime stressors (t=-2.17, p=0.04); however, there were no significant differences in subjective assessments of the perceived impact of stress on health. There was some evidence of shortened telomere length among Black respondents with more CD.
Discussion: Preliminary analyses provide evidence of triangulation. Future research will further explore associations between CD and telomere length among a larger sample (N=100) of Black and White American women