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[en] This booklet was produced as a result of the CCP6 Workshop on 'Molecular Quantum States at Dissociation', which was held in the Chemistry Department of University College London on 29th and 30th June, 1998. Each speaker in the workshop was invited to prepare a brief review of work in their own area, with references to their own and related work. The articles are designed to provide a good introduction to the field for workers outside it and an update for those more directly involved
[en] We investigate high-precision measurements beyond the standard quantum limit, utilizing nonclassical states. Although entanglement was considered a resource for achieving the Heisenberg limit in measurements, we show that any advantage expected from using entanglement is dependent on the measurement in question. We investigate several measurement scenarios and illustrate the role of entanglement as a resource for quantum high-precision measurement. In particular, we demonstrate that there is a regime wherein entanglement not only does not help, but prevents the achievement of the fundamental limit.
[en] The mass spectrum of diquark-antiquark is studied. The strong spin-spin force between two quarks inside a diquark causes a large mass splitting of about 200 MeV. The electromagnetic mass splitting of these mesons is also studied
[en] Wave equations make it possible to ascribe the quantum numbers to leptons theoretically. Minimal extension of the groups describing stable leptons led to three new types of groups. Each of them has an appropriate structure invariant ±1.0 and its own set of substructures having a physical interpretation in terms of stable leptons. The properties of the above-mentioned groups allow one to generate new types of equations and to relate them with two doublets (particle-antiparticle) of massive, charged unstable leptons and a doublet of massive unstable neutrinos.
[en] Students of quantum mechanics encounter discrete quantum numbers in a somewhat incoherent and bewildering number of ways. For each physical system studied, quantum numbers seem to be introduced in their own specific way, some enumerating from 1 and others from 0, without a common uniting thread. This essay presents a point of view that builds on dimensions, boundary conditions and various inputs that, while known, are often not brought together to present a simple, consistent picture. At the same time, some surprisingly sophisticated connections are also made.
[en] Quantum systems described by parametrized Hamiltinians are studied in a general context. Within this context, the classification scheme of Avron-Seiler-Simon for non-degenerate energy bands is extended to cover general parameter spaces, whole their sum rule is generalized to cover cases with degenerate bands as well. Additive topological quantum numbers are defined, and these are shown to be conserved in energy band ''collisions''. The conservation laws dictate that when some invariants are non-vanishing, no energy gap can develop in a set of degenerate bands. This gives rise to a series of splitting rules
[en] This paper describes a modification of the concept of probability associated with quantum mechanics by replacing the quantitative notion with a comparative one. The comparative concept is axiomatized and given a frequentist interpretation. It provides a more fundamental description of physical reality than does the quantitative concept. Of particular interest are the facts that comparative probability admits new models of random phenomena and that these new models intrinsically exhibit behaviour like that of complementarity as well as a new phenomenon of quantization of uncertainty. In particular this proposal leads to a comparative probability description of joint observations of complementary observables and an assertion that the usual application of the correspondence principle can be taken as rigorously correct rather than as an approximation based upon arbitrarily small h/2π or arbitrarily large quantum numbers. (Auth.)
[en] Motivated by the recent finding of five states by the LHCb collaboration, and the successful reproduction of three of them in a recent approach searching for molecular states of meson–baryon with the quantum numbers of , we extend these ideas and make predictions for the interaction of meson–baryon in the beauty sector, searching for poles in the scattering matrix that correspond to physical states. We find several states: two states with masses 6405 MeV and 6465 MeV for ; two more states with masses 6427 MeV and 6665 MeV for ; and three states between 6500 and 6820 MeV, degenerate with , stemming from the interaction of vector–baryon in the beauty sector.
[en] Line coupling and line mixing effects have been calculated for several self-broadened NH3 lines in parallel bands involving an excited ν2 mode. It is well known that once the ν2 mode is excited, the inversion splitting quickly increases as this quantum number increases. In the present study, we have shown that the ν2 dependence of the inversion splitting plays a dominant role in the calculated line-shape parameters. For the ν2 band with a 36 cm−1 splitting, the intra-doublet couplings practically disappear and for the 2ν2 and 2ν2 - ν2 bands with much higher splitting values, they are completely absent. With respect to the inter-doublet coupling, it becomes the most efficient coupling mechanism for the ν2 band, but it is also completely absent for bands with higher ν2 quantum numbers. Because line mixing is caused by line coupling, the above conclusions on line coupling are also applicable for line mixing. Concerning the check of our calculated line mixing effects, while the present formalism has well explained the line mixing signatures observed in the ν1 band, there are large discrepancies between the measured Rosenkranz mixing parameters and our calculated results for the ν2 and 2ν2 bands. In order to clarify these discrepancies, we propose to make some new measurements. In addition, we have calculated self-broadened half-widths in the ν2 and 2ν2 bands and made comparisons with several measurements and with the values listed in HITRAN 2012. In general, the agreements with measurements are very good. In contrast, the agreement with HITRAN 2012 is poor, indicating that the empirical formula used to predict the HITRAN 2012 data has to be updated. - Highlights: • New formalism is applied to calculate line shape parameters in parallel bands of NH3. • Theoretical results are compared with measurements in the ν2, 2ν2, and 2ν2-ν2 bands. • Half-widths and line mixing parameters strongly depend on excitation of the ν2 mode.