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  • 1
    Electronic Resource
    Electronic Resource
    The Berry connection and Born–Oppenheimer method (1992)
    College Park, Md. : American Institute of Physics (AIP)
    Journal of Mathematical Physics 33 (1992), S. 977-989 
    Details
    ISSN: 1089-7658
    Source: AIP Digital Archive
    Topics: Mathematics , Physics
    Notes: By performing the most general Born–Oppenheimer procedure, the (non-Abelian) Berry connection for quantum systems in a quantum environment is derived. This method is then applied to the rapid rotation of a particle about a slowly changing axis, as exemplified by the electronic motion of a diatomic molecule. The angular part of the resulting dynamics for the quantum environment is equivalent to that of a monopole.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.529751
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  • 2
    Electronic Resource
    Electronic Resource
    High-resolution crystals and preliminary X-ray diffraction studies of a catalytic RNA (1994)
    Copenhagen : International Union of Crystallography (IUCr)
    Acta crystallographica 50 (1994), S. 290-292 
    Details
    ISSN: 1399-0047
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: High-resolution single crystals of a catalytic RNA molecule derived from the sequence of the satellite RNA of tobacco ringspot virus have been obtained. The unit-cell volumes of the RNA crystals vary depending on the crystallization conditions and temperature. The best crystal form, when flash frozen, has space group P1 with unit-cell dimensions a = 53.08, b = 71.81, c = 28.03 Å, α = 98.43, β = 104.32 and γ = 74.54°. This form diffracts to a resolution of 2.4 Å. A heavy-atom derivative search is in progress.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0907444993013071
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  • 3
    Electronic Resource
    Electronic Resource
    Gamow-Jordan vectors and non-reducible density operators from higher-order S-matrix poles (1997)
    College Park, Md. : American Institute of Physics (AIP)
    Journal of Mathematical Physics 38 (1997), S. 6072-6100 
    Details
    ISSN: 1089-7658
    Source: AIP Digital Archive
    Topics: Mathematics , Physics
    Notes: In analogy to Gamow vectors that are obtained from first-order resonance poles of the S-matrix, one can also define higher-order Gamow vectors which are derived from higher-order poles of the S-matrix. An S-matrix pole of r-th order at zR=ER−iΓ/2 leads to r generalized eigenvectors of order k=0,1,...,r−1, which are also Jordan vectors of degree (k+1) with generalized eigenvalue (ER−iΓ/2). The Gamow-Jordan vectors are elements of a generalized complex eigenvector expansion, whose form suggests the definition of a state operator (density matrix) for the microphysical decaying state of this higher-order pole. This microphysical state is a mixture of non-reducible components. In spite of the fact that the k-th order Gamow-Jordan vectors has the polynomial time-dependence which one always associates with higher-order poles, the microphysical state obeys a purely exponential decay law. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.532203
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  • 4
    Electronic Resource
    Electronic Resource
    A quantum mechanical arrow of time and the semigroup time evolution of Gamow vectors (1995)
    College Park, Md. : American Institute of Physics (AIP)
    Journal of Mathematical Physics 36 (1995), S. 2593-2604 
    Details
    ISSN: 1089-7658
    Source: AIP Digital Archive
    Topics: Mathematics , Physics
    Notes: The exponential decay (or growth) of resonances provides an arrow of time which is described as the semigroup time evolution of Gamow vector in a new formulation of quantum mechanics. Another direction of time follows from the fact that a state must first be prepared before observables can be measured in it. Applied to scattering experiments, this produces another quantum mechanical arrow of time. The mathematical statements of these two arrows of time are shown to be equivalent. If the semigroup arrow is interpreted as microphysical irreversibility and if the arrow of time from the prepared in-state to its effect on the detector of a scattering experiment is interpreted as causality, then the equivalence of their mathematical statements implies that causality and irreversibility are interrelated. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.531053
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  • 5
    Electronic Resource
    Electronic Resource
    The relation between the Berry and the Anandan–Aharonov connections for U(N) bundles (1994)
    College Park, Md. : American Institute of Physics (AIP)
    Journal of Mathematical Physics 35 (1994), S. 1463-1470 
    Details
    ISSN: 1089-7658
    Source: AIP Digital Archive
    Topics: Mathematics , Physics
    Notes: The geometric phase has been defined as the holonomy of two bundles with different base spaces and different connections. In this article we establish the relation between the Berry–Simon and the Anandan–Aharonov definitions for a large class of cyclic Hamiltonians (with N-fold degeneracy) using the classifying theorem for principal fiber bundles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.530601
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  • 6
    Electronic Resource
    Electronic Resource
    Large cell anaplastic lymphoma: Evaluation of immunophenotype on paraffin and frozen sections in comparison with ultrastructural features (1991)
    Springer
    Virchows Archiv 418 (1991), S. 427-433 
    Details
    ISSN: 1432-2307
    Keywords: Large cell anaplastic lymphoma ; Electron microscopy ; Immunophenotyping
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Eleven cases of large cell anaplastic lymphoma (T typen=5, B typen=4, 0 typen=2) were investigated using electron microscopy and immunophenotyping on formalin-fixed paraffin sections and frozen sections of fresh tissue, to determine whether morphological criteria exist for the discrimination of T, B, and 0 phenotypes. Tumour cell lineage could not be established from ultrastructural features. On paraffin material monoclonal B-cell markers Ki-B5 and L-26 served as reliable tools for recognizing the B phenotype of large cell anaplastic lymphomas (previously determined on fresh material), whereas monoclonal antibodies MT1 (CD43) and UCHL1 (CD45RO) were of limited value in lineage determination.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01605929
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  • 7
    Electronic Resource
    Electronic Resource
    Relativistic and nonrelativistic dynamical groups (1993)
    Springer
    Foundations of physics 23 (1993), S. 751-767 
    Details
    ISSN: 1572-9516
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The physical motivations for the dynamical group are presented and it is shown how Barut's mathematical speculations were combined with the idea of an elementary length to provide group theoretical models of relativistic extended objects. Then the simplest nonrelativistic and relativistic models are described.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01883808
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  • 8
    Electronic Resource
    Electronic Resource
    Hilbert Space or Gel'fand Triplet. Time-Symmetric or Time-Asymmetric Quantum Mechanics (1999)
    Springer
    International journal of theoretical physics 38 (1999), S. 115-130 
    Details
    ISSN: 1572-9575
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Intrinsic microphysical irreversibility is thetime asymmetry observed in exponentially decayingstates. It is described by the semigroup generated bythe Hamiltonian H of the quantum physical system, not by the semigroup generated by a Liouvillian Lwhich describes the irreversibility due to the influenceof an external reservoir or measurement apparatus. Thesemigroup time evolution generated by H is impossible in the Hilbert space (HS) theory, which allowsonly time-symmetric boundary conditions and a unitarygroup time evolution. This leads to problems with decayprobabilities in the HS theory. To overcome these and other problems (nonexistence of Dirac kets)caused by the Lebesgue integrals of the HS, one extendsthe HS to a Gel'fand triplet, which contains not onlyDirac kets, but also generalized eigenvectors of the self-adjoint H with complex eigenvalues(ER – iΓ/2) and a Breit-Wignerenergy distribution. These Gamow statesψG have a time-asymmetric exponentialevolution. One can derive the decay probability of the Gamow state into the decay productsdescribed by Λ from the basic formula of quantummechanics ℘(t) = Tr(|ψG ›‹ψG|Λ), which in HS quantum mechanicsis identically zero. From this result one derives the decay rate ℘(t) and all the standard relations between℘(0), Γ, and the lifetimeτR used in the phenomenology of resonancescattering and decay. In the Born approximation oneobtains Dirac's Golden Rule.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1026681123555
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  • 9
    Electronic Resource
    Electronic Resource
    The Berry phase in molecular physics (1992)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 41 (1992), S. 53-75 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The geometric phase of quantum mechanics is introduced, and its physical effects are then studied in the context of molecular physics. By performing the most general Born-Oppenheimer procedure, we show how gauge groups appear in the study of molecules. This method is then applied to the doubly degenerate Λ-levels of a diatomic molecule. The resulting dynamics for the slow angular motion of the dumbbell is equivalent to that of a Dirac monopole.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560410108
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