Particle physics implications of Wilkinson microwave anisotropy project measurements

We present an overview of the implications of the WMAP data for particle physics. The standard parameter set ∈, η and ξ characterising the inflaton potential can be related to the power-law indices characterising deviation of the CMB spectrum from the scale invariant form. Different classes of inflation potentials are in turn naturally associated with different unified schemes. At present WMAP does not exclude any but a few simple unified models. In particular, hybrid models favoured by supersymmetric unification continue to be viable. However future improvement in data leading to better determination of the ‘running’ of power-law indices should help to narrow the possibilities for unified models. The main conclusion is that WMAP is consistent with the paradigm of GUT scale (10¹⁶ GeV) inflation.     

Extended WKB Method,Resonances and Supersymmetric Radial Barriers

Semiclassical approximations are implemented in the calculation of position and width of low-energy resonances for radial barriers. The numerical integrations are delimited by τ/τ _life≪8, with τ the period of a classical particle in the barrier trap and τ _life the resonance lifetime. These energies are used in the construction of ‘haired’ short-range potentials as the supersymmetric partners of a given radial barrier. The new potentials could be useful in the study of the transient phenomena which give rise to the Moshinsky’s diffraction in time.     

Wigner distributions for finite dimensional quantum systems: An algebraic approach

We discuss questions pertaining to the definition of ‘momentum’, ‘momentum space’, ‘phase space’ and ‘Wigner distributions’; for finite dimensional quantum systems. For such systems, where traditional concepts of ‘momenta’ established for continuum situations offer little help, we propose a physically reasonable and mathematically tangible definition and use it for the purpose of setting up Wigner distributions in a purely algebraic manner. It is found that the point of view adopted here is limited to odd dimensional systems only. The mathematical reasons which force this situation are examined in detail     

On the Complete Classification of Unitary <Emphasis Type="Italic">N</Emphasis> = 2 Minimal Superconformal Field Theories

Aiming at a complete classification of unitary N = 2 minimal models (where the assumption of space-time supersymmetry has been dropped), it is shown that each modular invariant candidate partition function of such a theory is indeed the partition function of a fully-fledged unitary N = 2 minimal model, subject to the assumptions that orbifolding is a ‘physical’ process and that the space-time supersymmetric A{\mathcal{A}} -D{\mathcal{D}} -E{\mathcal{E}} models are physical. A family of models constructed via orbifoldings of either the diagonal model or of the space-time supersymmetric exceptional models then demonstrates that there exists a unitary N = 2 minimal model for every one of the allowed partition functions in the list obtained from Gannon’s work (Gannon in Nucl Phys B 491:659–688, 1997).     

Against ‘Realism’

We examine the prevalent use of the phrase “local realism” in the context of Bell’s Theorem and associated experiments, with a focus on the question: what exactly is the ‘realism’ in ‘local realism’ supposed to mean? Carefully surveying several possible meanings, we argue that all of them are flawed in one way or another as attempts to point out a second premise (in addition to locality) on which the Bell inequalities rest, and (hence) which might be rejected in the face of empirical data violating the inequalities. We thus suggest that the phrase ‘local realism’ should be banned from future discussions of these issues, and urge physicists to revisit the foundational questions behind Bell’s Theorem.     

An invitation to higher gauge theory

In this easy introduction to higher gauge theory, we describe parallel transport for particles and strings in terms of 2-connections on 2-bundles. Just as ordinary gauge theory involves a gauge group, this generalization involves a gauge ‘2-group’. We focus on 6 examples. First, every abelian Lie group gives a Lie 2-group; the case of U(1) yields the theory of U(1) gerbes, which play an important role in string theory and multisymplectic geometry. Second, every group representation gives a Lie 2-group; the representation of the Lorentz group on 4d Minkowski spacetime gives the Poincaré 2-group, which leads to a spin foam model for Minkowski spacetime. Third, taking the adjoint representation of any Lie group on its own Lie algebra gives a ‘tangent 2-group’, which serves as a gauge 2-group in 4d BF theory, which has topological gravity as a special case. Fourth, every Lie group has an ‘inner automorphism 2-group’, which serves as the gauge group in 4d BF theory with cosmological constant term. Fifth, every Lie group has an ‘automorphism 2-group’, which plays an important role in the theory of nonabelian gerbes. And sixth, every compact simple Lie group gives a ‘string 2-group’. We also touch upon higher structures such as the ‘gravity 3-group’, and the Lie 3-superalgebra that governs 11-dimensional supergravity.     

How To Play Two-Player Restricted Quantum Games with 10 Cards

We show that it is possible to play ‘restricted’ two-player quantum games proposed originally by Marinatto and Weber (Phys. Lett. A 272:291–303, 2000) by purely macroscopic means, in the simplest case having as the only equipment a pack of 10 cards. Our example shows also that some apparently ‘genuine quantum’ results, even those that emerge as a consequence of dealing with entangled states, can be obtained by suitable application of Kolmogorovian probability calculus and secondary-school mathematics, without application of the ‘Hilbert space machinery’.     

Managing, profiling and analyzing a library of 2.6 million compounds gathered from 32 chemical providers

Summary The data for 3.8 million compounds from structural databases of 32 providers were gathered and stored in a single chemical database. Duplicates are removed using the IUPAC International Chemical Identifier. After this, 2.6 million compounds remain. Each database and the final one were studied in term of uniqueness, diversity, frameworks, ‘drug-like’ and ‘lead–like’ properties. This study also shows that there are more than 87 000 frameworks in the database. It contains 2.1 million ‘drug-like’ molecules among which, more than one million are ‘lead-like’. This study has been carried out using ‘ScreeningAssistant’, a software dedicated to chemical databases management and screening sets generation. Compounds are stored in a MySQL database and all the operations on this database are carried out by Java code. The druglikeness and leadlikeness are estimated with ‘in–house’ scores using functions to estimate convenience to properties; unicity using the InChI code and diversity using molecular frameworks and fingerprints. The software has been conceived in order to facilitate the update of the database. ‘ScreeningAssistant’ is freely available under the GPL license.     

Emerging molecular diversity from the intra-molecular Ugi reaction: iterative efficiency in medicinal chemistry

This review details a now established area within the isonitrile multi-component reaction (IMCR) field of study, namely employing bi-functional reagents in the Ugi reaction for the construction of screening sets with the additional element or even possibly ‘metric’ of enhanced ‘iterative efficiency potential’ The concept of ‘iterative efficiency’ will be briefly introduced, coupled with discussion on new synthetic routes to select bi-functional IMCR precursors and their use in the generation of pharmacologically relevant ‘molecular diversity’     

The capture of slow antiprotons in helium, neon and argon

We consider the capture of antiprotons with energies less than roughly 27 eV by helium, neon and argon atoms. We use the adiabatic ‘hidden-crossing’ theory to calculate both the capture cross-sections and the angular distribution of the antiprotons. We find that important differences between helium and the other noble gases can be attributed to the properties of the ‘hidden’ crossings appropriate to each system. This revised version was published online in August 2006 with corrections to the Cover Date.     

Strong pionic intermittency in ‘cold’ events in12C-AgBr interactions at 4.5 A GeV

In this paper intermittent behaviour of the pions from ‘cold’ and ‘hot’ classes of events from¹²C-AgBr interactions at 4.5 A GeV has been studied, separately. The results reveal strong intermittent pattern in case of ‘cold’ class of events.     

Fragmentation function and hadronic production of the heavy supersymmetric hadrons

The light top-squark may be the lightest squark, and its lifetime may be ‘long enough’ in a kind of SUSY models that have not been ruled out yet experimentally, so colorless ‘supersymmetric hadrons (superhadrons)’ (q is a quark excluding the t-quark) may be formed as long as the light top-squark can be produced. The fragmentation function of into heavy ‘supersymmetric hadrons (superhadrons)’ (Q̄=c̄ or b̄) and hadronic production of the superhadrons are investigated quantitatively. The fragmentation function is calculated precisely. Due to the difference in spin of the SUSY component, the asymptotic behavior of the fragmentation function is different from those of the existing ones. The fragmentation function is also applied to compute the production of heavy superhadrons at the hadronic colliders Tevatron and LHC in the so-called fragmentation approach. The resultant cross-section for the heavy superhadrons is too small to observe at Tevatron, but large enough at LHC, when all the relevant parameters in the SUSY models are taken within the favored region for the heavy superhadrons. The production of ‘light superhadrons’ (q=u,d,s) is also roughly estimated with the same SUSY parameters. It is pointed out that the production cross-sections of the light superhadrons may be much greater than those of the heavy superhadrons, so that even at Tevatron the light superhadrons may be produced in great quantities. PACS 12.38.Bx; 13.87.Fh; 12.60.Jv; 14.80.Ly     

Schrödinger’s Cat Meets Einstein’s Twins: A Superposition of Different Clock Times

The phenomenon of quantum superposition, which allows a physical system to exist in different states ‘simultaneously’, is one of the most bizarre notions in physics. Here we illustrate an even more bizarre example of it: a superposed state of a physical system consisting of both an ‘older’ version and a ‘younger’ version of that system. This can be accomplished by exploiting the special relativistic effect of time dilation featuring in Einstein’s famous twin paradox.     

Contextuality and Nonlocality in ‘No Signaling’ Theories

We define a family of ‘no signaling’ bipartite boxes with arbitrary inputs and binary outputs, and with a range of marginal probabilities. The defining correlations are motivated by the Klyachko version of the Kochen-Specker theorem, so we call these boxes Kochen-Specker-Klyachko boxes or, briefly, KS-boxes. The marginals cover a variety of cases, from those that can be simulated classically to the superquantum correlations that saturate the Clauser-Horne-Shimony-Holt inequality, when the KS-box is a generalized PR-box (hence a vertex of the ‘no signaling’ polytope). We show that for certain marginal probabilities a KS-box is classical with respect to nonlocality as measured by the Clauser-Horne-Shimony-Holt correlation, i.e., no better than shared randomness as a resource in simulating a PR-box, even though such KS-boxes cannot be perfectly simulated by classical or quantum resources for all inputs. We comment on the significance of these results for contextuality and nonlocality in ‘no signaling’ theories.     

Dynamics of multiparticle systems with non–abelian symmetry

We consider the dynamics governing the evolution of a many body system constrained by a nonabelian local symmetry. We obtain explicit forms of the global macroscopic condition assuring that at the microscopic level the evolution respects the overall symmetry constraint. We demonstrate the constraint mechanisms for the case of SU(2) system comprising particles in fundamental, and adjoint representations (‘nucleons’ and ‘pions’). Received: 10 March 2000 / Revised version: 7 July 2000/ Published online: 8 December 2000     

Continuity of a Quantum Stochastic Process

We investigate a quantum counterpart of the classical notion of a stochastic process continuous with probability one, and prove that the L ²-limit of quantum martingales ‘continuous with probability one’ is a quantum martingale ‘continuous with probability one’. Applications of this result to a number of concrete situations is presented.     

Temperature dependence of the sensitivity of a long-range surface plasmon optical sensor

The temperature dependence of the sensitivity of an optical sensor based on long-range surface plasmon resonance (LRSPR) is studied via theoretical modeling. Both the ‘angular interrogation’ and the ‘wavelength interrogation’ modes of operation are studied. In addition, the variation of the full width at half maximum of the LRSPR ‘reflectance dip’ is also studied as a function of temperature, which ultimately determines the temperature dependence of the sensitivity of the sensor when the reflectance is monitored at a fixed incident angle (‘reflectance interrogation’). It is found that while most of the time only the ‘reflectance interrogation’ mode leads to improved sensitivity for the LRSPR sensor compared to a conventional SPR sensor, the temperature stability of the operation of the LRSPR sensor is generally higher than (or at least comparable to) that of the SPR sensor. PACS 73.20.Mf; 07.07.Df     

Signature splitting in magnetic rotational bands

Nearly-spherical nuclei in three mass regions have recently been observed to exhibit rotational-like features. We have identified almost 80 such bands; largest number (43) lie in the lead region. Most of these bands are assigned oblate multi-quasiparticle configurations. Their interpretation in terms of ‘magnetic rotation’ does not allow for signature splitting in these bands. We have however found signature splitting as well as signature inversion in many bands. We apply the two-quasiparticle plus rotor model to understand the occurrence of signature splitting vis-a-vis the role of ‘shears mechanism’ in these bands.     

Studies of polarization/self-depolarization and electret-type effect in AgI

A novel d.c. polarization/self-depolarization study and electret-type effect in AgI are reported. AgI pellets of varying thicknesses, placed between two blocking (graphite) electrodes, were subjected to an external d.c. potential. A state of complete polarization was attained within ∼10 min, irrespective of the sample thickness. At this state, the potential difference, developed across the sample pellet as a result of polarization/accumulation of mobile Ag⁺ ions at the bulk/negative electrode interface, was measured experimentally. The potential difference, obtained immediately after the removal of the external d.c. source, has been referred to as ‘instant peak potential (V_p)’. As soon as the external voltage source is switched off, a process of self-depolarization is initiated due to the chemical/self diffusion of polarized mobile Ag⁺ ions throughout the bulk. ‘V_p’ gives a direct information regarding the extent of mobile ion concentration (n). ‘V_p’ measurements were carried out as a function of temperature and ‘Log V_p vs 1/T’ variation was compared with the ‘Log n vs 1/T’ Arrhenius plot, reported earlier in an entirely independent study. The two variations are almost analogous. This, in turn, supported as an earlier assertion that the abrupt conductivity increase in α-AgI, after β→α-phase transition at ∼147 °C, is predominantly due to the excessive increase in ‘n’. Furthermore, it has also been revealed that the Ag⁺ ions play another unique role which led to the existence of ‘persistent polarization’ states in AgI. These states are identical to the ‘electret-type effects’, observed in a number of dielectric materials. The polarization state persisted for very long time in ‘thermally stimulated polarized’ sample. A detailed investigation of the persistence/retention of polarization in the thermally-stimulated-polarized sample is reported.