Lower bound of minimal time evolution in quantum mechanics

We show that the total time of evolution from the initial quantum state to final quantum state and then back to the initial state, i.e., making a round trip along the great circle over S^2, must have a lower bound in quantum mechanics, if the difference between two eigenstates of the 2\times 2 Hamiltonian is kept fixed. Even the non-hermitian quantum mechanics can not reduce it to arbitrarily small value. In fact, we show that whether one uses a hermitian Hamiltonian or a non-hermitian, the required minimal total time of evolution is same. It is argued that in hermitian quantum mechanics the condition for minimal time evolution can be understood as a constraint coming from the orthogonality of the polarization vector \bf P of the evolving quantum state \rho={1/2}(\bf 1+ \bf{P}\cdot\boldsymbol{\sigma}) with the vector \boldsymbol{\mathcal O}(\Theta) of the 2\times 2 hermitian Hamiltonians H ={1/2}({\mathcal O}_0\boldsymbol{1}+ \boldsymbol{\mathcal O}(\Theta)\cdot\boldsymbol{\sigma}) and it is shown that the Hamiltonian H can be parameterized by two independent parameters {\mathcal O}_0 and \Theta.Comment: 4 pages, no figure, revtex

Physical Aspects of Pseudo-Hermitian and PTPT-Symmetric Quantum Mechanics

For a non-Hermitian Hamiltonian H possessing a real spectrum, we introduce a canonical orthonormal basis in which a previously introduced unitary mapping of H to a Hermitian Hamiltonian h takes a simple form. We use this basis to construct the observables O of the quantum mechanics based on H. In particular, we introduce pseudo-Hermitian position and momentum operators and a pseudo-Hermitian quantization scheme that relates the latter to the ordinary classical position and momentum observables. These allow us to address the problem of determining the conserved probability density and the underlying classical system for pseudo-Hermitian and in particular PT-symmetric quantum systems. As a concrete example we construct the Hermitian Hamiltonian h, the physical observables O, the localized states, and the conserved probability density for the non-Hermitian PT-symmetric square well. We achieve this by employing an appropriate perturbation scheme. For this system, we conduct a comprehensive study of both the kinematical and dynamical effects of the non-Hermiticity of the Hamiltonian on various physical quantities. In particular, we show that these effects are quantum mechanical in nature and diminish in the classical limit. Our results provide an objective assessment of the physical aspects of PT-symmetric quantum mechanics and clarify its relationship with both the conventional quantum mechanics and the classical mechanics.Comment: 45 pages, 13 figures, 2 table

Navigating Work-Life Integration, Legal Issues, Patient Safety: Lessons for Work-Life Wellness in Academic Medicine: Part 1 of 3

In this series of three manuscripts, we will explore real-life scenarios encountered by clinicians, learners, and researchers in healthcare, which challenge our assumptions and our understanding of how to navigate issues as diverse as mental health, racial diversity, gender discrimination, imposter syndrome, and substance use disorder

Fibre bundle formulation of nonrelativistic quantum mechanics: I. Introduction. The evolution transport

We propose a new systematic fibre bundle formulation of nonrelativistic quantum mechanics. The new form of the theory is equivalent to the usual one but it is in harmony with the modern trends in theoretical physics and potentially admits new generalizations in different directions. In it a pure state of some quantum system is described by a state section (along paths) of a (Hilbert) fibre bundle. Its evolution is determined through the bundle (analogue of the) Schr\"odinger equation. Now the dynamical variables and the density operator are described via bundle morphisms (along paths). The mentioned quantities are connected by a number of relations derived in this work. The present first part of this investigation is devoted to the introduction of basic concepts on which the fibre bundle approach to quantum mechanics rests. We show that the evolution of pure quantum-mechanical states can be described as a suitable linear transport along paths, called evolution transport, of the state sections in the Hilbert fibre bundle of states of a considered quantum system.Comment: 26 standard (11pt, A4) LaTeX 2e pages. The packages AMS-LaTeX and amsfonts are required. Revised: new material, references, and comments are added. Minor style chages. Continuation of quan-ph/9803083. For continuation of the this series see http://www.inrne.bas.bg/mathmod/bozhome

Population-Based Study of Acute Respiratory Infections in Children, Greenland

Acute respiratory infections (ARI) are frequent in Inuit children, in terms of incidence and severity. A cohort of 294 children <2 years of age was formed in Sisimiut, a community on the west coast of Greenland, and followed from 1996 to 1998. Data on ARI were collected during weekly visits at home and child-care centers; visits to the community health center were also recorded. The cohort had respiratory symptoms on 41.6% and fever on 4.9% of surveyed days. The incidence of upper and lower respiratory tract infections was 1.6 episodes and 0.9 episodes per 100 days at risk, respectively. Up to 65% of the episodes of ARI caused activity restriction; 40% led to contact with the health center. Compared with studies from other parts of the world, the incidence of ARI appears to be high in Inuit children

The differential interaction of snRNPs with pre-mRNA reveals splicing kinetics in living cells

GFP-tagged snRNP components reveal the dynamics and rate for spliceosome assembly in vivo

The Long Exception: Rethinking the Place of the New Deal in American History

The Long Exception examines the period from Franklin Roosevelt to the end of the twentieth century and argues that the New Deal was more of an historical aberration—a byproduct of the massive crisis of the Great Depression—than the linear triumph of the welfare state. The depth of the Depression undoubtedly forced the realignment of American politics and class relations for decades, but, it is argued, there is more continuity in American politics between the periods before the New Deal order and those after its decline than there is between the postwar era and the rest of American history. Indeed, by the early seventies the arc of American history had fallen back upon itself. While liberals of the seventies and eighties waited for a return to what they regarded as the normality of the New Deal order, they were actually living in the final days of what Paul Krugman later called the interregnum between Gilded Ages. The article examines four central themes in building this argument: race, religion, class, and individualism

Intravenous antibiotics for pulmonary exacerbations in people with cystic fibrosis

BACKGROUND: Cystic fibrosis is a multi-system disease characterised by the production of thick secretions causing recurrent pulmonary infection, often with unusual bacteria. Intravenous antibiotics are commonly used in the treatment of acute deteriorations in symptoms (pulmonary exacerbations); however, recently the assumption that exacerbations are due to increases in bacterial burden has been questioned. OBJECTIVES: To establish if intravenous antibiotics for the treatment of pulmonary exacerbations in people with cystic fibrosis improve short- and long-term clinical outcomes. SEARCH METHODS: We searched the Cochrane Cystic Fibrosis Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. We also searched the reference lists of relevant articles and reviews and ongoing trials registers.Date of last search of Cochrane trials register: 27 July 2015. SELECTION CRITERIA: Randomised controlled trials and the first treatment cycle of cross-over studies comparing intravenous antibiotics (given alone or in an antibiotic combination) with placebo, inhaled or oral antibiotics for people with cystic fibrosis experiencing a pulmonary exacerbation. DATA COLLECTION AND ANALYSIS: The authors assessed studies for eligibility and risk of bias and extracted data. MAIN RESULTS: We included 40 studies involving 1717 participants. The quality of the included studies was largely poor and, with a few exceptions, these comprised of mainly small, inadequately reported studies.When comparing treatment with a single antibiotic to a combined antibiotic regimen, those participants receiving a combination of antibiotics experienced a greater improvement in lung function when considered as a whole group across a number of different measurements of lung function, but with very low quality evidence. When limited to the four placebo-controlled studies (n = 214), no difference was observed, again with very low quality evidence. With regard to the review's remaining primary outcomes, there was no effect upon time to next exacerbation and no studies in any comparison reported on quality of life. There were no effects on the secondary outcomes weight or adverse effects. When comparing specific antibiotic combinations there were no significant differences between groups on any measure. In the comparisons between intravenous and nebulised antibiotic or oral antibiotic (low quality evidence), there were no significant differences between groups on any measure. No studies in any comparison reported on quality of life. AUTHORS' CONCLUSIONS: The quality of evidence comparing intravenous antibiotics with placebo is poor. No specific antibiotic combination can be considered to be superior to any other, and neither is there evidence showing that the intravenous route is superior to the inhaled or oral routes. There remains a need to understand host-bacteria interactions and in particular to understand why many people fail to fully respond to treatment