121267185
Properties of excited states in Ge77
The nucleus $^{77}\mathrm{Ge}$ was studied through the $^{76}\mathrm{Ge}(^{13}\mathrm{C},^{12}\mathrm{C})^{77}\mathrm{Ge}$ reaction at a sub-Coulomb energy. The angular distributions of $\ensuremath{\gamma}$ rays depopulating excited states in $^{77}\mathrm{Ge}$ were measured in order to constrain spin and parity assignments. Some of these assignments are of use in connection with neutrinoless double beta decay, where the population of states near the Fermi surface of $^{76}\mathrm{Ge}$ was recently explored using transfer reactions.
13327837
First experiment with HELIOS: the structure of 13B.
A first experiment is reported that makes use of a new kind of spectrometer uniquely suited to the study of reactions with radioactive beams in inverse kinematics, the helical orbit spectrometer, HELIOS. The properties of some low-lying states in the neutron-rich N=8 nucleus 13B were studied with good resolution. From the measured angular distributions of the (d,p) reaction and the relative spectroscopic factors, spin and configuration assignments of the first- and third-excited states of this nucleus can be constrained.
117805675
Entropy Defined, Entropy Increase and Decoherence Understood, and Some Black-Hole Puzzles Solved
Statistical mechanics explains thermodynamics in terms of (quantum) mechanics by equating the entropy of a microstate of a closed system with the logarithm of the number of microstates in the macrostate to which it belongs, but the question `what is a macrostate?' has never been answered except in a vague, subjective, way. However Hawking's discovery of black hole evaporation led to a formula for black hole entropy with no subjective element. In this letter, we argue from this result, together with the assumption that `black hole thermodynamics is just ordinary thermodynamics applied to black holes', that a macrostate for a general (quantum gravitational) closed system is an equivalence class of matter-gravity microstates with the same expectation values for the matter degrees of freedom alone. Not only does this finally answer the question `what is entropy?', but it also predicts the equality of the thermodynamic entropy of a black hole with the matter and the gravity entropy-like quantities derived from the Euclidean path integral. Furthermore it gives us a clear glimpse of an ultimate synthesis of quantum theory and gravity in which we see that (a) gravity acts as a universal environment, thus predicting that, if the initial state of the universe is unentangled, its entropy must go on increasing forever, (b) the gravitational field has degrees of freedom, but no observables, thus enabling gravity to perform the trick of providing an objective continual process of decoherence. All the above rests on the validity of unitarity. The `information-loss puzzle' had raised doubts about that. But we suggest a resolution for this puzzle.
124668258
Purification of Kms States
On presente des resultats fondamentaux sur les etats KMS a partir d'une approche nouvelle suggeree a la fois par le probleme de purification et aussi par la situation de Bisognano-Wichmaun