118824876
Chiral three-point interactions in 5 and 6 dimensions
A bstractWe study $ \mathcal{N}=\left( {N,0} \right) $ super-Poincaré invariant six-dimensional massless and five-dimensional massive on-shell amplitudes. We demonstrate that in six dimensions, all possible three-point amplitudes involving self-dual tensor multiplets are necessarily embedded in gravitational theories. To obtain non-gravitational amplitudes, we study instead five-dimensional chiral massive amplitudes which can be considered as the KK reduction of six-dimensional chiral theories. We indeed find non-gravitational amplitudes whose on-shell degrees of freedom are shown to match those of the massive particle states that arise from self-dual strings wrapping a circle. Along the way we find interesting hints of a fermionic symmetry in the (2, 0) theory, which accompanies the self-dual tensor gauge symmetry. We also discuss novel theories with (3, 0) and (4, 0) supersymmetry.
118461064
The Grainy multiverse
I consider a landscape containing three vacua and study the topology of global spacelike slices in eternal inflation. A discrete toy model, which generalizes the well studied Mandelbrot model, reveals a rich phase structure. Novel phases include monochromatic tubular phases, which contain crossing curves of only one vacuum, and a democratic tubular phase, which contains crossing curves of all three types of vacua. I discuss the generalization to realistic landscapes consisting of many vacua. Generically, the system ends up in a grainy phase, which contains no crossing curves or surfaces and consists of packed regions of different vacua. Other topological phases arise on the scale of several generations of nucleations.
117771864
Holographic definition of points and distances
We discuss the way in which field theory quantities assemble the spatial geometry of three-dimensional anti\char21{}de Sitter space (${\mathrm{AdS}}_{3}$). The field theory ingredients are the entanglement entropies of boundary intervals. A point in ${\mathrm{AdS}}_{3}$ corresponds to a collection of boundary intervals which is selected by a variational principle we discuss. Coordinates in ${\mathrm{AdS}}_{3}$ are integration constants of the resulting equation of motion. We propose a distance function for this collection of points, which obeys the triangle inequality as a consequence of the strong subadditivity of entropy. Our construction correctly reproduces the static slice of ${\mathrm{AdS}}_{3}$ and the Ryu-Takayanagi relation between geodesics and entanglement entropies. We discuss how these results extend to quotients of ${\mathrm{AdS}}_{3}$\char22{}the conical defect and the BTZ geometries. In these cases, the set of entanglement entropies must be supplemented by other field theory quantities, which can carry the information about lengths of nonminimal geodesics.
84181918
Bulk curves from boundary data in holography
We embed spherical Rindler space—a geometry with a spherical hole in its center—in asymptotically anti– de Sitter (AdS) spacetime and show that it carries a gravitational entropy proportional to the area of the hole. Spherical AdS-Rindler space is holographically dual to an ultraviolet sector of the boundary field theory given by restriction to a strip of finite duration in time. Because measurements have finite durations, local observers in the field theory can only access information about bounded spatial regions. We propose a notion of differential entropy that captures uncertainty about the state of a system left by the collection of local, finite-time observables. For two-dimensional conformal field theories we use holography and the strong subadditivity of entanglement to propose a formula for differential entropy and show that it precisely reproduces the areas of circular holes in AdS3. Extending the notion to field theories on strips with variable durations in time, we show more generally that differential entropy computes the areas of all closed, inhomogeneous curves on a spatial slice of AdS3. We discuss the extension to higher-dimensional field theories, the relation of differential entropy to entanglement between scales, and some implications for the emergence of space from the renormalization group flow of entangled field theories.
16140829
Typicality versus thermality: an analytic distinction
In systems with a large degeneracy of states such as black holes, one expects that the average value of probe correlation functions will be well approximated by the thermal ensemble. To understand how correlation functions in individual microstates differ from the canonical ensemble average and from each other, we study the variances in correlators. Using general statistical considerations, we show that the variance between microstates will be exponentially suppressed in the entropy. However, by exploiting the analytic properties of correlation functions we argue that these variances are amplified in imaginary time, thereby distinguishing pure states from the thermal density matrix. We demonstrate our general results in specific examples and argue that our results apply to the microstates of black holes.
118485314
A novel channel for vacuum decay
Abstract I show that cosmological bubble walls in the thin wall approximation are unstable to the creation of “barnacles” – loci of different wall tension adjacent to regions filled with a third vacuum. Barnacle formation appears to have the same observational consequences as the extensively studied bubble collision scenario, but occurs exponentially more often. The process is described by a saddle point of the thin wall action with two negative modes.
14231355
Discriminant analysis and secondary-beam charge recognition
The discriminant-analysis method has been applied to optimize the exotic-beam charge recognition in a projectile fragmentation experiment. The experiment was carried out at the GSI using the fragment separator (FRS) to produce and select the relativistic secondary beams, and the ALADIN setup to measure their fragmentation products following collisions with Sn target nuclei. The beams of neutron poor isotopes around La-124 and Sn-107 were selected to study the isospin dependence of the limiting temperature of heavy nuclei by comparing with results for stable Sn-124 projectiles. A dedicated detector to measure the projectile charge upstream of the reaction target was not used, and alternative methods had to be developed. The presented method, based on the multivariate discriminant analysis, allowed to increase the efficacy of charge recognition up to about 90%, which was about 20% more than achieved with the simple scalar methods.
16807669
Nuclear multifragmentation and fission: Similarity and differences
Thermal multifragmentation of hot nuclei is interpreted as the nuclear liquid–fog phase transition inside the spinodal region. The experimental data for p(8.1GeV)+Au collisions are analyzed. It is concluded that the decay process of hot nuclei is characterized by two size parameters: one density at the transition state and one at the kinetic freeze-out. The similarity between the dynamics of fragmentation and ordinary fission is discussed. The IMF emission time is related to the mean rupture time at the multiscission point, which corresponds to the kinetic freeze-out configuration.
118568605
Mass and isospin dependence in multifragmentation
Challenging motivations for isotopic studies in nuclear multifragmentation are derived from the the importance of the density dependence of the symmetry term of the nuclear equation of state for astrophysical applications and for effects linked to the manifestation of the nuclear liquid-gas phase transition. In a recent experiment with the ALADIN spectrometer at GSI, the possibility of using secondary beams for reaction studies at relativistic energies has been explored. Beams of $^{107}$Sn, $^{124}$Sn, $^{124}$La, and $^{197}$Au were used to investigate the mass and isospin dependence of multifragmentation. The status of the project and first results are reported and discussed.
14871446
Isotopic dependence of the caloric curve
Isotopic effects in projectile fragmentation at relativistic energies have been studied with the ALADIN forward spectrometer at SIS. Stable and radioactive Sn and La beams with an incident energy of 600 MeV per nucleon have been used in order to explore a wide range of isotopic compositions. Chemical freeze-out temperatures are found to be nearly invariant with respect to the A/Z ratio of the produced spectator sources, consistent with predictions for expanded systems. Consequences for the proposed interpretation of chemical breakup temperatures as representing the limiting temperatures predicted by microscopic models are discussed.