Some Thoughts on the Quantum Theory of de Sitter Space

This is a summary of two lectures I gave at the Davis Conference on Cosmic Inflation. I explain why the quantum theory of de Sitter (dS) space should have a finite number of states and explore gross aspects of the hypothetical quantum theory, which can be gleaned from semiclassical considerations. The constraints of a self-consistent measurement theory in such a finite system imply that certain mathematical features of the theory are unmeasurable, and that the theory is consequently mathematically ambiguous. There will be a universality class of mathematical theories all of whose members give the same results for local measurements, within the {\it a priori} constraints on the precision of those measurements, but make different predictions for unmeasurable quantities, such as the behavior of the system on its Poincare recurrence time scale. A toy model of dS quantum mechanics is presented.Comment: Talk presented at Davis Inflation Meeting, 2003 {astro-ph/0304225

A New Approach to the Phenomenology of Cosmological Supersymmetry Breaking

I introduce a new low energy effective description of Cosmological SUSY breaking. It requires the existence of a strongly interacting gauge theory at a scale of order $10^3$ GeV, some of whose fields carry standard model quantum numbers. SUSY breaking is communicated to the standard model through gaugino masses and the Higgs multiplets. The model also provides a possible new solution of the strong CP problemComment: JHEP Latex, 17 page

Remodeling the Pentagon After the Events of 2/23/06

The meta-stable SUSY breaking mechanism of Intriligator Seiberg and Shih can be used to simplify the Pentagon model of TeV scale physics. The simplified model has only a single scalar field and no troublesome low energy axion. One significant signature is $l^+ l^- X$ plus missing energy, where $X$ might be the two photons of gauge mediated models, but is likely to be different. There is a new strongly interacting sector with a scale around 1.5 TeV. The penta-hadrons of this sector have masses of order 6 TeV or more. Dark matter is probably the pseudo-goldstone boson of spontaneously broken penta-baryon number. This can be a viable dark matter candidate if an appropriate asymmetry in penta-baryon number is generated in the early universe. The pseudo-Goldstone particle has a mass of $\sim 1$ eV and is produced predominantly in flavor changing charged current decays of ordinary particles. The model solves the flavor problems of SUSY, but has two low energy CP violating phases, whose value is strongly constrained by experiment.Comment: JHEP Latex, 20 pages, 1 axodraw figur

Locality and the classical limit of quantum mechanics

I argue that conventional estimates of the criterion for classical behavior of a macroscopic body are incorrect, because they do not take into account the locality of interactions, which characterizes the behavior of all systems described approximately by local quantum field theory. Black holes are the only localized objects which do not have such a description. The deviations from classical behavior of a macroscopic body, except for those which can be described as classical uncertainties in the initial values of macroscopic variables,are {\it exponentially} small as a function of the volume of the macro-system in microscopic units.Comment: 16 pages, LaTe

SUSY Breaking, Cosmology, Vacuum Selection and the Cosmological Constant in String Theory

This is the written version of a talk given at the Santa Barbara Workshop on Supersymmetry in December of 1995. It summarizes a collection of results on superstring cosmology obtained by the author and various collaborators, and contains some speculations about the resolution of the cosmological constant and vacuum selection problems in string theory.Comment: 24 pages, harvma

Some Thoughts on the Quantum Theory of Stable de Sitter Space

I review and update ideas about the quantum theory of de Sitter space. New results include a quantum relation between energy and entropy of states in the causal patch, which is satisfied by small dS black holes. I also discuss the preliminaries of a quantum theory in global coordinates, which is invariant under a q-deformed version of the de Sitter supergroup. In this context I outline an algebraic derivation of the CSB scaling relation between Poincare SUSY breaking and the dS radius. I also review recent work on infra-red divergences in dS/CFT, as well as the phenomenology of CSB. I show that a coincidence been two scales in the phenomenological model is explained by insisting on the existence of galaxies.Comment: JHEP3 Latex, 40 pages, 1 eps figur

Entropy and initial conditions in cosmology

I discuss the Boltzmann-Penrose question of why the initial conditions for cosmology have low entropy. The modern version of Boltzmann's answer to this question, due to Dyson, Kleban and Susskind, seems to imply that the typical intelligent observer arises through thermal fluctuation, rather than cosmology and evolution. I investigate whether this can be resolved within the string landscape. I end with a review of the suggestion that Holographic Cosmology provides a simpler answer to the problem. This paper is a revision of unpublished work from the spring of 2006, combined with my talk at the Madrid conference on String theory and Cosmology, Nov 2006.Comment: JHEP Latex, 37 page

Holographic Space-time from the Big Bang to the de Sitter era

I review the holographic theory of space-time and its applications to cosmology. Much of this has appeared before, but the discussion is more unified and concise. I also include some material on work in progress, whose aim is to understand compactification in terms of finite dimensional super-algebras. This is an expanded version of a lecture I gave at the conference on Liouville Quantum Gravity and Statistical Systems, in memory of Alexei Zamolodchikov, at the Poncelet Institute in Moscow, 21-24 June, 2008.Comment: 30 pages, LaTeX, Expanded version of a lecture given at the Conference on Liouville Quantum Gravity and Statistical Systems, in honor of Alexei Zamolodchikov, Poncelet Institute, Mosco

Cosmological Supersymmetry Breaking and the Power of the Pentagon: A Model of Low Energy Particle Physics

I present a low energy Lagrangian implementing the idea of Cosmological SUSY breaking (CSB). The model predicts ${\rm tan}\beta \sim 1$, and incorporates a new mechanism for breaking of $SU(2)\times U(1)$. The Higgs mass is determined by new physics and can evade the bounds of the MSSM. The model resolves the CP and flavor problems of SUSY. The up quark mass is non-vanishing. An axion-like particle, with TeV scale decay constant, appears inevitably. Such a particle is experimentally ruled out if it has conventional QCD axion couplings. The problem {\it may} be avoided by adding dimension 5 operators, which explicitly break the axial symmetry, but this probably introduces a strong CP problem.Comment: JHEP latex, 30 pages, Version 2: Revised discussion of Strong CP violation. The dimension 5 operator, introduced to avoid observational problems with the light axion, also reintroduces the strong CP proble

SUSY and the Holographic Screens

The Cartan-Penrose (CP) equation is interpreted as a connection between a spinor at a point in spacetime, and a pair of holographic screens on which the information at that point may be projected. Local SUSY is thus given a physical interpretation in terms of the ambiguity of the choice of holographic screen implicit in the work of Bousso. The classical CP equation is conformally invariant, but quantization introduces metrical information via the B(ekenstein)-H(awking)-F(ischler)-S(usskind)-B(ousso) connection between area and entropy. A piece of the classical projective invariance survives as the $(-1)^F$ operation of Fermi statistics. I expand on a previously discussed formulation of quantum cosmology, using the connection between SUSY and screens