Parisi's Hypercube, Fock-Space Frustration, and Near-AdS_{2}/Near-CFT_{1} Holography.

We consider a model of Parisi where a single particle hops on an infinite-dimensional hypercube, under the influence of a uniform but disordered magnetic flux. We reinterpret the hypercube as the Fock-space graph of a many-body Hamiltonian and the flux as a frustration of the return amplitudes in Fock-space. We will identify the set of observables that have the same correlation functions as the double-scaled Sachdev-Ye-Kitaev (DS-SYK) model, and hence the hypercube model is an equally good quantum model for near-AdS_{2}/near-CFT_{1} (NAdS_{2}/NCFT_{1}) holography. Unlike the SYK model, the hypercube Hamiltonian is not p local. Instead, the SYK model can be understood as a Fock-space model with similar frustrations. Hence we propose this type of Fock-space frustration as the broader characterization for NAdS_{2}/NCFT_{1} microscopics, which encompasses the hypercube and the DS-SYK models as two specific examples. We then speculate on the possible origin of such frustrations.

Onset of Quantum Chaos in Random Field Theories.

We study the quantum Lyapunov exponent λ_{L} in theories with spacetime-independent disorder. We first derive self-consistency equations for the two- and four-point functions for products of N models coupled by disorder at large N, generalizing the equations appearing in SYK-like models. We then study families of theories in which the disorder coupling is an exactly marginal deformation, allowing us to follow λ_{L} from weak to strong coupling. We find interesting behaviors, including a discontinuous transition into chaos, mimicking classical KAM theory.

Realization of the SU(N) Kondo effect in a strong magnetic field.

In this Letter we suggest a realization of the SU(N) Kondo effect, using quantum dots at strong magnetic field. We propose using edge states of the quantum Hall effect as pseudospin that interact with multiple quantum dots structures. In the suggested realization one can access each pseudospin separately and hence may perform a set of experiments that were impossible until now. We focus on the realization of SU(2) and SU(3) Kondo effects and find in the unitary limit a conductivity of 3/4 quantum conductance in the SU(3) case.

High density preheating effects on Q-ball decays and inflation in the minimal supersymmetric standard model.

Nonperturbative preheating decay of postinflationary condensates often results in a high density, low momenta, nonthermal gas. In the case where the nonperturbative classical evolution also leads to Q balls, this effect shields them from instant dissociation, and may radically change the thermal history of the Universe. For example, in a large class of inflationary scenarios, motivated by the minimal supersymmetric standard model and its embedding in string theory, the reheat temperature changes by a multiplicative factor of 10(12).

Baryogenesis from the Kobayashi-Maskawa phase.

The smallness of quark masses suppresses the CP violation from the Kobayashi-Maskawa phase to a level that is many orders of magnitude below what is required to explain the observed baryon asymmetry. We point out that if, as a result of time variation in the Yukawa couplings, quark masses were large at the time of the electroweak phase transition, then the Kobayashi-Maskawa mechanism could be the source of the asymmetry. The Froggatt-Nielsen mechanism provides a plausible framework where the Yukawa couplings could all be of order 1 at that time, and settle to their present values before nucleo-synthesis. The problems related to a strong first order electroweak phase transition may also be alleviated in this framework. Our scenario reveals a loophole in the commonly held view that the Kobayashi-Maskawa mechanism cannot be the dominant source of CP violation to play a role in baryogenesis.