4,264 research outputs found
The H\"older Inequality for KMS States
We prove a H\"older inequality for KMS States, which generalises a well-known
trace-inequality. Our results are based on the theory of non-commutative
-spaces.Comment: 10 page
Hepatitis B and C virus infections and liver function in AIDS patients at Chris Hani Baragwanath Hospital, Johannesburg
Background: Impaired liver function tests and co-infection with hepatitis viruses in AIDS patients are common in western countries.Objective: To assess liver function and prevalence of co-infection with hepatitis B and hepatitis C viruses in AIDS patients at Chris Hani Baragwanath Hospital.Design: A prospective study.Setting: Chris Hani Baragwanath Hospital, Johannesburg, South Africa.Patients: One hundred consecutive patients with AIDS admitted to Chris Hani Baragwanath Hospital.Results: There were 52 males and 48 females aged 16 to 54 years (mean + SD: 34.6 + 7.5 years). The results of laboratory test were as follows: LFTs: bilirubin 11.8 (+15.6) ìmol/ l; AST: 79.6 (±116.6) iu/L; alkaline phosphatase: 204.3 (±237.4) iì/L; albumin: 23.9 (±6.2) g/l; CD4+ Iymphocytes: 141.5 (±168.6) ìl; CD8+: 666.9 (±618.3) ìl; HBV - HbsAg: 6 (6%); HbsAg + eAg: 3 (3%); previous disease (Anti HBs and/or anti HBc): 35%, HCV: 1(1%).Conclusion: Liver function tests were impaired in the majority of patients with AIDS (93%) in our setting. Evidence of previous and present HBV infection was present in 41%. This is different from what is observed in western countries (90-95%). The results also suggest that patients here acquired HBV infection while still immuno competent. HCV infectionwas rare
Existence of long-lived isotopes of a superheavy element in natural Au
Evidence for the existence of long-lived isotopes with atomic mass numbers
261 and 265 and abundance of (1-10)x10 relative to Au has been found in
a study of natural Au using an inductively coupled plasma - sector field mass
spectrometer. The measured masses fit the predictions made for the masses of
Rg and Rg (Z=111) and for some isotopes of nearby elements.
The possibility that these isotopes belong to the recently discovered class
of long-lived high spin super- and hyperdeformed isomeric states is discussed.Comment: 4 pages, 3 figures, 2 table
Quantum mechanics on manifolds and topological effects
A unique classification of the topological effects associated to quantum
mechanics on manifolds is obtained on the basis of the invariance under
diffeomorphisms and the realization of the Lie-Rinehart relations between the
generators of the diffeomorphism group and the algebra of infinitely
differentiable functions on the manifold. This leads to a unique
("Lie-Rinehart") C* algebra as observable algebra; its regular representations
are shown to be locally Schroedinger and in one to one correspondence with the
unitary representations of the fundamental group of the manifold. Therefore, in
the absence of spin degrees of freedom and external fields, the first homotopy
group of the manifold appears as the only source of topological effects.Comment: A few comments have been added to the Introduction, together with
related references; a few words have been changed in the Abstract and a Note
added to the Titl
Full density matrix dynamics for large quantum systems: Interactions, Decoherence and Inelastic effects
We develop analytical tools and numerical methods for time evolving the total
density matrix of the finite-size Anderson model. The model is composed of two
finite metal grains, each prepared in canonical states of differing chemical
potential and connected through a single electronic level (quantum dot or
impurity). Coulomb interactions are either excluded all together, or allowed on
the dot only. We extend this basic model to emulate decoherring and inelastic
scattering processes for the dot electrons with the probe technique. Three
methods, originally developed to treat impurity dynamics, are augmented to
yield global system dynamics: the quantum Langevin equation method, the well
known fermionic trace formula, and an iterative path integral approach. The
latter accommodates interactions on the dot in a numerically exact fashion. We
apply the developed techniques to two open topics in nonequilibrium many-body
physics: (i) We explore the role of many-body electron-electron repulsion
effects on the dynamics of the system. Results, obtained using exact path
integral simulations, are compared to mean-field quantum Langevin equation
predictions. (ii) We analyze aspects of quantum equilibration and
thermalization in large quantum systems using the probe technique, mimicking
elastic-dephasing effects and inelastic interactions on the dot. Here, unitary
simulations based on the fermionic trace formula are accompanied by quantum
Langevin equation calculations
Towards a definition of quantum integrability
We briefly review the most relevant aspects of complete integrability for
classical systems and identify those aspects which should be present in a
definition of quantum integrability.
We show that a naive extension of classical concepts to the quantum framework
would not work because all infinite dimensional Hilbert spaces are unitarily
isomorphic and, as a consequence, it would not be easy to define degrees of
freedom. We argue that a geometrical formulation of quantum mechanics might
provide a way out.Comment: 37 pages, AmsLatex, 1 figur
Vertex operators and the geometry of moduli spaces of framed torsion-free sheaves
We define complexes of vector bundles on products of moduli spaces of framed
rank r torsion-free sheaves on the complex projective plane. The top
non-vanishing Chern classes of the cohomology of these complexes yield actions
of the r-colored Heisenberg and Clifford algebras on the equivariant cohomology
of the moduli spaces. In this way we obtain a geometric realization of the
boson-fermion correspondence and related vertex operators.Comment: 36 pages; v2: Definition of geometric Heisenberg operators modified;
v3: Minor typos correcte
Rigorous Dynamics and Radiation Theory for a Pauli-Fierz Model in the Ultraviolet Limit
The present paper is devoted to the detailed study of quantization and
evolution of the point limit of the Pauli-Fierz model for a charged oscillator
interacting with the electromagnetic field in dipole approximation. In
particular, a well defined dynamics is constructed for the classical model,
which is subsequently quantized according to the Segal scheme. To this end, the
classical model in the point limit is reformulated as a second order abstract
wave equation, and a consistent quantum evolution is given. This allows a study
of the behaviour of the survival and transition amplitudes for the process of
decay of the excited states of the charged particle, and the emission of
photons in the decay process. In particular, for the survival amplitude the
exact time behaviour is found. This is completely determined by the resonances
of the systems plus a tail term prevailing in the asymptotic, long time regime.
Moreover, the survival amplitude exhibites in a fairly clear way the Lamb shift
correction to the unperturbed frequencies of the oscillator.Comment: Shortened version. To appear in J. Math. Phy
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