Proton decay in supersymmetric models

We discuss proton decay in supersymmetric theories. We find that it is possible to obtain rates which are comparable with those of standard SU(5). In the presence of a discrete symmetry which occurs in an SU(5) supersymmetric unified model we obtain a definite prediction for the dominant decay mode, i.e. p → K^+?ν_μ and n → K^0?ν_μ.     

The synthesis and conformational analysis of optical isomers of 4-phenyl-perhydropyrido[1,2-a]pyrazine-1,3-dione: an example of ‘solid state–frozen’ dynamics in nitrogen-bridged bicyclic 2,6-diketopiperazines

The synthesis, chemical properties, and conformational analysis of enantiopure (4R,9aS)-, (4S,9aR)-, (4S,9aS)-, and (4R,9aR)-4-phenyl-perhydropyrido[1,2-a]pyrazine-1,3-diones having potential biological activity are described. An interesting example of the coexistence of two invertomers of the (4R,9aR)-diastereomer in a single crystal unit cell is reported. The invertomers differ in the cis/trans-relationship between the fused rings and in the absolute configuration at the chiral nitrogen atom. The structure and equilibrium distributions of the respective conformers have been determined by NMR spectroscopy in both polar and non-polar solvents at various temperatures. The NMR spectra show that dynamic processes in the imide parts of the interconverting species are restrained by self-aggregation. The (4S,9aR)-diastereomer exists in a single conformation with insignificant dynamic effects.     

Anticipating a new Golden Age

The standard model of fundamental interactions is remarkably successful, but it leaves an unfinished agenda. Several major questions seem ripe for exploration in the near future. I anticipate that the coming decade will be a Golden Age of discovery in fundamental physics.     

Stability criteria for breached-pair superfluidity

We present simple, concrete, two-fermion models that exhibit thermodynamically stable isotropic translationally invariant gapless superfluid states (breached-pair superfluidity). The mass ratio between the components and the momentum structure of the interaction are crucial for determining the stability of such states: idealized, momentum-independent ("contact") interactions are insufficient.     

Hawking radiation As tunneling

We present a short and direct derivation of Hawking radiation as a tunneling process, based on particles in a dynamical geometry. The imaginary part of the action for the classically forbidden process is related to the Boltzmann factor for emission at the Hawking temperature. Because the derivation respects conservation laws, the exact spectrum is not precisely thermal. We compare and contrast the problem of spontaneous emission of charged particles from a charged conductor.