122854596
STRIPPING REACTIONS AND THE STRUCTURE OF LIGHT AND INTERMEDIATE NUCLEI
A reduced width connecting two nuclear levels contains information about the structure of the states involved. Techniques are described whereby such information can be cast into useable form: the formalism so developed is then applied to an analysis of stripping widths. The various kinds of information about the structure of nuclei which can be obtained from an analysis of stripping widths are reviewed and what is known about the single-particle reduced widths is collected and summarized. A number of experiments of particuiar interest for future study are discussed. (W.D.M.)
28323659
Symmetries and quantum chaos: Time-reversal invariance in the nucleon-nucleon interaction.
Let \ensuremath{\alpha} be the relative norm of a symmetry-breaking term in the Hamiltonian of a many-particle system, and \ensuremath{\Lambda} the energy-dependent transition parameter which charcterizes the quantum chaos via spectral and strength fluctuations. Combining a compact theory for \ensuremath{\Lambda}/${\mathrm{\ensuremath{\alpha}}}^{2}$ with fluctuation theories by which \ensuremath{\Lambda} can be deduced from (neutron-resonance) data gives, for the time-reversal-noninvariant nucleon-nucleon interaction, \ensuremath{\alpha}\ensuremath{\le}(1\char21{}2)\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}3}$, which would improve with better small-strength data in nuclei with dense spectra. Diffusion equations involving \ensuremath{\Lambda} as the ``time'' variable are also discussed.
11400551
Bound on time-reversal noninvariance in the nuclear Hamiltonian.
Energy-level fluctuations are calculated by random-matrix methods, for time-reversal noninvariant (TRNI) Hamiltonians. The theory, applied to the data, shows that in the neutron and proton resonance regions, for heavy and intermediate nuclei (i.e., respectively), the local rms off-diagonal multiparticle H(TRNI) matrix element < or approx. = D/10, with D the level spacing. Spectral averaging methods reduce this to a bound on the nucleon-nucleon TRNI vs TRI interactions. First calculations, for /sup 169/Er, give a 1% upper bound.
123029512
Statistical properties of many-particle spectra V. Fluctuations and symmetries
Abstract The manner in which energy-level and strength fluctuations change as a good symmetry is gradually broken is studied for a wide variety of chaotic systems describable in terms of random-matrix models. The local parameter Λ which governs the transition is identified as the mean-square symmetry-breaking matrix element in units of the local average spacing; its basic significance is clarified by exhibiting it as the “time” variable in a hierarchic set of diffusion equations. While many transitions, including Poisson → GOE, are considered, the transition GOE → GUE, from Gaussian orthogonal to Gaussian unitary ensembles, is studied in particular detail because of its connection with the breaking of time-reversal invariance (TRI), especially in complex nuclei for which the relevance of the GOE has been experimentally confirmed (GOE → GUE enters also into the study of chaotic magnetic systems). It is shown that the ensemble theory is directly applicable to real systems so that the transition equations derived for various spectral and strength measures can be applied to fluctuation data to give multiparticle bounds on the TRI-breaking part of the Hamiltonian. Analyses of spectral and strength fluctuations in the nuclear neutron-resonance and proton-resonance regions give bounds on the symmetry-breaking matrix elements as approximately one-tenth of the local average spacing. The analysis however must not stop with determining a bound on Λ; although the mere existence of a nonzero Λ could be of interest, indicating the occurrence of a symmetry breaking, the significance, if any, of an upper bound will usually not be obvious. It is therefore essential to determine, from the local multibody parameter Λ, the global (two-body) quantity α, the relative norm of the time-reversal noninvariant (TRNI) part of the nucleon-nucleon interaction. We do that in the following paper.
120306861
Nuclear Level Densities and Partition Functions with Interactions
A general theory, based on central limit theorems and unitary-group decompositions of the microscopic H, is given for the nuclear level density. The density appears in terms of convolutions of noninteracting-particle densities with easily calculable interaction functions given explicitly in terms of the Hamiltonian matrix elements.
121774358
Electromagnetic sum rules by spectral distribution methods
118419469
Inflation from Strongly Coupled Gauge Dynamics
We argue, using a phenomenological holographic approach, that walking, strongly coupled gauge theories generate a suitable potential for a small field inflation model. We show that the effective description is a model of a single inflaton. We determine the tunings necessary in the gauge sector to generate inflation and overcome the \eta problem.
119206061
Hadronization at the AdS wall
We describe hadronization events, using the AdS/CFT Correspondence, which display many of the qualitative features expected in QCD. In particular we study the motion of strings with separating end points in a back-reacted hard wall geometry. The solutions show the development of a linear QCD-like string. The end points oscillate in the absence of string breaking. We introduce string breaking by hand and evolve the new state forward in time to observe the separation of two string segments. A kink associated with this breaking evolves to the end points of the string inducing rho meson production. We explicitly compute the rho meson production at the end point.