Physical Sciences and Mathematics Commons^™

Theoretical Studies Of The Energies And Geometries Of Strained Hydrocarbons, Mitchell Alan Miller

Dissertations, Theses, and Capstone Projects

Theoretical models are used to explore problems of interest to organic chemists in four projects. The first three apply existing methodologies to investigate a series of strained cyclic hydrocarbon molecules; the fourth develops methodology.

Project I. Semiempirical calculations have been performed on a variety of hydrocarbons composed of fused cyclobutane rings using the MNDO, AM1 and MM2 methods. The systems studied include linearly concatenated cyclobutanes (ladderanes), cyclic structures (prismanes) and two 'star-shaped' C₂₄H₂₄ hydrocarbons, helvetane and israelane. The results reported include optimized geometries, heats of formation and vibrational frequencies. The performance of the theoretical models is evaluated …

A Current Algebra For Some Gauge Theory Amplitudes, V. Parameswaran Nair

Publications and Research

The classical amplitude for scattering of two positive helicity and n-2 negative helicity (or the other way) gauge bosons is shown to be generated by a Wess-Zumino-Witten (WZW) model for N= 4 supersymmetric gauge theory; i.e. the current algebra of the WZW model (with central charge k= 1 ) gives a Kac-Moody algebra as the symmetry behind these amplitudes.

Multi Gluon Scattering: A String Based Calculation, David Kosower, Bum-Hoon Lee, V. Parameswaran Nair

Publications and Research

We suggest the use of open bosonic string theory to compute multigluon scattering in QCD, since gauge invariance ,cyclic symmetry etc. are manifest in this approach. The method is illustrated by the computation of five gluon scattering.

Ni(Ii) (Dioxo[16]Anen5)-Induced Methane Formation From Methyl Coenzyme M, Charles Michael Drain, Barry B. Cordon, David B. Sable

Publications and Research

The nickel tetrapyrrole containing factor, F430, is implicated in the final methane evolution step in methanogenic ba~terial-~ and has attracted considerable a t t e n t i ~ n . ~T- ~he essential role of F430 in methane formation was demonstrated by Ankel-Fuchs and Thauer, who reported the in vitro catalysis of H3CSCH2CH2S03-, methyl coenzyme M (methyl-CoM), to methane and CoM by purified methyl-CoM reductase under reducing condit i o n ~ .S~in ce F,,o exists in both the Ni(1) (or Ni(II1)) and the Ni(I1) states in Methanobacterium thermoautotrophicum,loi,t ll is of interest to examine the role of the …

¿Conservar, Para Qué?, Aldemaro Romero Jr.

Publications and Research

No abstract provided.

New National Park For Venezuela, Aldemaro Romero Jr.

Publications and Research

No abstract provided.

Compactification Of The Twisted Heterotic String, V. Parameswaran Nair, Alfred Shapere, Andrew Strominger, Frank Wilczek

Publications and Research

We consider compactifications of the recently discovered tachyon free non-supersymmetric string on tori of Lorentzian self dual lattices. The one loop cosmological constant is computed as a function of the parameters characterizing the lattices. When the lattice parameters are treated as dynamical variables, their equations of motion require extremization of A. This extremization determines the allowed gauge groups and mass spectra. We explicitly find some extremes of A, valid to all orders in perturbation theory. A very general duality relation between compactifications is demonstrated, which leads to an equivalence of compactifications on tori of radii R aud 1/R.

Reversible Oxygenation Of Oxygen Transport Proteins, Charles Michael Drain, Barry B. Cordon

Publications and Research

A lecture demonstration illustrating changes in the visible spectra of oxygen transport proteins upon reversihle oxygen binding is reported. The coloration upon exposure to oxygen is dramatic. Deoxyhemoglobin changes from purple to red, deoxyhemocyanin is transformed from colorless to blue, while colorless deoxyhemerythrin turns red. This demonstration illustrates an interesting example of a chemically reversible reaction and is used in the discussion of basic thermodynamic properties. A comparison of the physical characteristics of these oxveen storaee and transn.o rt ~ro- A teins is provided to illustrate the stru&ral diversity associated with these proteins having a similar biological role.

General Results On Glueball Masses In Qcd, I. J. Muzinich, V. Parameswaran Nair

Publications and Research

A number of authors have investigated mass inequalities for mesons and baryons in QCD. These provide rigorous nonperturbative constraints on the mass spectrum. Similar inequalities for glueballs are investigated. For nonzero spin J, in the large-N_c approximation, m_J ^- ⩾ m_J⁺ is found. (For J = 0, the existence of a gluon condensate can modify this statement.) There are also constraints on how fast m_J can grow with J. For example, for m_J = a + bJ^α, 0 ⩽ α ⩽ 1 is found, a result consistent with Regge behaviour.

Structural And Topological Contributions To The Electronic Properties Of Inhomogeneous Media (Fractal, Electrode, Impedance), Michael Kramer

Dissertations, Theses, and Capstone Projects

Recent theoretical developments in the theory of inhomogeneous media have enabled Physicists to explore various properties of random composites. We demonstrate how these techniques can be applied to the treatment of electrochemical systems, specifically porous structures. A Random Network Model is introduced to represent the porous electrode immersed in electrolyte, and using numerical simulation the a.c. impedance behavior of the system is explored. We explore how various compositional and structural parameters contribute to the electrical properties of the system. The topology of our model is analyzed, and the effect of fractal structures on impedance behavior is considered. To examine the …

Qcd Vacuum As A Chromomagnetic Superconductor: Microscopic Physics, V. Parameswaran Nair, C. Rosenzweig

Publications and Research

The compactness of the QCD gauge group leads to the existence of chromomagnetic monopole configurations. The interactions of these monopoles are studied using electric-magnetic duality as a guide. It is shown that the gluon-monopole interaction acquires an extra minus sign which tends to destabilize the monopole configurations. A model is presented which exploits this observation. We present a scenario where the monopoles condense, giving chromomagnetic superconductivity, via a first-order phase transition at a scale where the electric and magnetic charges are equal, i.e., α = 1/2 . In this vacuum medium gluons propagate like 1/k⁴ which is now seen …

La Nueva Revolución Será Azul, Aldemaro Romero Jr.

Publications and Research

No abstract provided.

Que La Luz De La Sabiduría Ilumine Nuestras Cuevas, Aldemaro Romero Jr.

Publications and Research

No abstract provided.

(Super)Conformal Symmetry Breaking, Andrew Strominger, V. Parameswaran Nair

Publications and Research

We argue that the only consistent way to break conformal invariance in a quantum theory of gravity is spontaneously in a finite locally conformal supersymmetric theory. This generically occurs whenever scalar fields are present. Covariant surface-integral expressions for the super-charge and four-momentum in terms of asymptotically constant spinor fields are derived. These are used to discuss stability and other aspects of the theory.

Bags Vs. Strings: Hadrons In Type I And Type Ii Superconducting Vacua, V. Parameswaran Nair, C. Rosenzweig

Publications and Research

Two popular models for hadronic structure are bags and strings. Both involve analogies with superconductivity. We claim that the most appropriate analogies are type I superconductors for bags and type II superconductors for strings. The structures of hadrons is somewhat different for the two situations. In principle, and in practice in the real world, it is the similarities which are most important. These include linear confining potentials, linearly rising Regge trajectories and short distance Coulomb potentials. These are all generic properties of bound states in a superconductor and the main distinctions between bags and strings is under what circumstances these …

Difference Equations, Isoperimetric Inequality And Transience Of Certain Random Walks, Jozef Dodziuk

Publications and Research

No abstract provided.

Mixing Angles, B-Meson Life-Time In The Six-Quark Model Based On So(10) X U(1)Pq, V. Parameswaran Nair, Louis Michel, Kameshwar C. Wali

Publications and Research

We show that a recently proposed multigenerational, grand unified model with three parameters (top-quark mass and two phases of Higgs vacuum expectation values) yields results in good agreement with the most recent phenomenological limits placed on the weak mixing angles of the quarks. These limits take into account the experimental value for B-meson life-time.

Peccei-Quinn Symmetry As Flavor Symmetry And Grand Unification, Aharon Davidson, V. Parameswaran Nair, Kameshwar C. Wali

Publications and Research

We consider the possibility of identifying the Peccei-Quinn (PQ) symmetry as also the flavor symmetry in multigenerational grand unification schemes. The essential ingredient, a global, axial U(1) symmetry in the PQ mechanism to avoid the strong CP-violation problem provides useful constraints on the fermion —Higgs-boson couplings in the theory, thereby leading to identical "canonical" forms for fermion mass matrices in both the charged sectors. These forms are the conjectured Fritzsch-type matrices exhibiting the "nearest-neighbor" interactions in generation space. From among the popular schemes for grand unification, SO(10) emerges as one which has several advantages over the others for constructing multigenerational …

Totally Empirical Wavefunctions From X-Ray Diffraction Data, Martin Jeffry Goldberg

Dissertations, Theses, and Capstone Projects

The interpretation of coherent x-ray diffraction experiments by a quantum model is described. Adjusting the coefficients of an LCAO expansion to best fit measured Bragg intensities results in a totally empirical quantum wavefunction. The quantum model is compared to a multipole expansion. The constraints imposed by quantum mechanics are examined, and several methods of satisfying these constraints while best fitting a wavefunction to measured Bragg intensities are detailed. Application is made to beryllium metal, with a resultant fit R(,1) = .00249. Similar applications to graphite and diamond are outlined. The formalism is extended to explicitly include solid-state effects, and this …

Low-Mass Solitons From Fractional Charges In Quantum Chromodynamics, A. P. Balachandran, V. Parameswaran Nair, N. Panchapakesan, S. G. Rajeev

Publications and Research

Slansky, Goldman, and Shaw have proposed a model to account for the observation of fractionally charged states. We show that in this model, there are expected to be several low-mass solitons (four being in the mass range ∼20-60 MeV) associated with the third homotopy group π₃(SU(3)/SO(3))=Z₄, besides a low-mass (∼30 MeV) Z₂ monopole. Confirmation of these levels and hence of the model has important implications for Cabrera's results on the magnetic monopole. An efficient algorithm for the calculation of π3(G/H) for a general Lie group G and a subgroup H is developed. It is pointed …

Breakdown Of Flavor Conservation In A Monopole Background, V. Parameswaran Nair

Publications and Research

We give a simple derivation of the catalysis of baryon decay and other flavor-changing processes by monopoles. The role of the axial anomaly is clarified. A general current-algebraic argument which clarifies the nature of flavor violation is also given.

Catalysis Of Flavor Nonconservation By Monopoles, V. Parameswaran Nair

Publications and Research

A simple argument based on current algebra is given to show how monopoles can lead to baryon decay and other flavor-changing processes.

Order Of Phase Transitions In A Field Theory, V. Parameswaran Nair

Publications and Research

The relation between the gauge or global nature of a symmetry being broken and the order of the associated phase transition is clarified. First-order phase transitions in gauge theories are related to the asymptotic freedom of the Φ³ interaction in six dimensions. Spontaneous violation of lepton number in the standard electroweak theory provides a nontrivial illustration of our results.

Second-Order Phase Transitions, Inflationary Universe, And Formation Of Galaxies, V. Parameswaran Nair

Publications and Research

At the critical point of a second-order phase transition, statistical fluctuations are correlated and enhanced in amplitude. We explore this phenomenon in the early universe as a possible mechanism for the formation of galaxies. In an inflationary universe, such dynamical effects on galactic scales are consistent with the constraints imposed by the horizon. Spontaneous breakdown of lepton number provides a model where these ideas are realized. The two-point correlation function for density fluctuations is calculated and agrees with the observed correlation for galaxies. An estimate of the density contrast is shown to be of the required magnitude.

Generalized Bohr-Sommerfeld Rules For Anomalies With Applications To Symmetry Breakdown And Decoupling, A. P. Balachandran, V. P. Nair, C. G. Trahern

Publications and Research

In the presence of anomalies, the requirement that a classical symmetry group G has a proper action on the fermion measure or in the effective Lagrangian description imposes Bohr-Sommerfeld conditions on the anomalies, and often implies that G is broken to a subgroup H as well. We show these results in this paper and apply them to QCD and SU(5). In particular, constraints on the QCD order parameter are derived, and an argument is presented which suggests that the breakdown of the chiral flavor symmetry and the emergence of some sort of generation structure in QCD may be natural.

Soliton States In The Quantum-Chromodynamic Effective Lagrangian, A. P. Balachandran, V. Parameswaran Nair, S. G. Rajeev, A. Stern

Publications and Research

The work of Skyrme has shown that the SU(2)×SU(2) chiral model has nontrivial topological sectors which admit solitons for generic chiral Lagrangians. In this paper, we study such models in the presence of baryon fields. The baryon number and strangeness of the solitons, and the bound states of the nucleon to the soliton are investigated. It is found that long-lived levels with large baryon number B and strangeness (≳6 in magnitude) and masses somewhere in the range 1.8 to 5.6 GeV must exist. Some of these levels have half-integral electric charge and exotic relation between B and spin s (e.g., …

The Theory And Synthesis Of [2.2.2] Propellane, Theodore Mark Prociv

Dissertations, Theses, and Capstone Projects

INDO calculations indicated that the triplet state of dimethylene cyclohexane could rearrange to gometrically relaxed triplets which should collapse preferentially to the ground state [2.2.2] Propellane. A mercury sensitized photolysis of the dimethylene cyclohexane did in fact result in detectable quantities of the propellane, trapped as 1,4 dibromobicyclo octane. Synthesis of 1,4 dibromobicyclo octane and 1,1,6,6 tetradeuterodimethylene-cyclohexane are presented in the dissertation. Included in the dissertation are the results of INDO calculations of various propellane isomers having nitrogens and borons in the bridgehead positions.

Exotic Levels From Topology In The Quantum-Chromodynamic Effective Lagrangian, A. P. Balachandran, V. Parameswaran Nair, S. G. Rajeev, A. Stern

Publications and Research

Skyrme has shown that the SU ⊗ SU(2) chiral model has nontrivial topological sectors with static solutions for suitable Lagrangians. The baryon number B and strangeness of these sectors have been studied, and the existence of bound states of the nucleon field to the lightest solitons is shown. It is found that there must be long-lived levels with |B|≳6 and |s|≳6 and 1.8 GeV≲m≲5.6 GeV, some having half-integral charge and exotic relation between B and s, that can be pair produced in, say, e+e− collisions.

Aspects Of Duality In Chiral Field Theories, A. P. Balachandran, V. Parameswaran Nair, B. S. Skagerstam, C. G. Trahern

Publications and Research

The Abelian and non-Abelian gauge potentials A_uv are known to describe chiral fields. Here we study their interactions with dual extended objects. The region occupied by these objects is shown to behave like a distinct phase of chiral fields which is nondissipative under suitable geometric conditions. A method for the realization of the 't Hooft algebra in these systems is outlined. The concept of electric and magnetic duality in electromagnetism is generalized to chiral fields with values in a symmetric space.

Nonperturbative Proof Of The Non-Abelian Anomalies, A. P. Balachandran, G. Marmo, V. P. Nair, C. G. Trahern

Publications and Research

We give a nonperturbative derivation of non-Abelian anomalies.