The Theory of the Quantum World

The following sections are included:

• The International Solvay Institutes

• The Theory of the Quantum World Chair: Professor David Gross

• Opening Session

• Contents

The following sections are included:

• Introduction

• Soda and Energy

• Positivism and Progress

• International Connections

• The Council of 1911

• Works Cited

• References

• Murray Gell-Mann: From Solvay 1961 to Solvay 2011

I ask the question: What can we infer about the nature and structure of the physical world (a) from experiments already done to test the predictions of quantum mechanics (b) from the assumption that all future experiments will agree with those predictions? I discuss existing and projected experiments related to the two classic paradoxes of quantum mechanics, named respectively for EPR and Schrödinger's Cat, and show in particular that one natural conclusion from both types of experiment implies the abandonment of the concept of macroscopic counterfactual definiteness.

This article reviews how interactions between atoms can be engineered by means of external fields, and how those interactions may be used to build quantum information processing devices and simulators. It also describes some of the obstacles one has to overcome in order to build such devices, as well as their potential impact in other branches of Physics.

I present a selective survey of the phases of quantum matter with varieties of many particle quantum entanglement. I classify the phases as gapped, conformal, or compressible quantum matter. Gapped quantum matter is illustrated by a simple discussion of the ℤ₂ spin liquid, and connections are made to topological field theories. I discuss how conformal matter is realized at quantum critical points of realistic lattice models, and make connections to a number of experimental systems. Recent progress in our understanding of compressible quantum phases which are not Fermi liquids is summarized. Finally, I discuss how the strongly-coupled phases of quantum matter may be described by gauge-gravity duality. The structure of the N_c→∞ limit of SU(N_c) gauge theory, coupled to adjoint fermion matter at non-zero density, suggests aspects of gravitational duals of compressible quantum matter.

2011 marked the hundredth anniversary both of the famous Solvay conferences, and of the Geiger-Marsden experiment that launched the modern understanding of subatomic structure. I was asked to survey the status and prospects of particle physics for the anniversary Solvay conference, with appropriate perspective. This is my attempt.

This is a very general overview of the quantum mechanics of spacetime, starting from some generalities and then moving on to more current developments in string theory.

The following sections are included:

• Alain Aspect: Foundations of Quantum Mechanics and Quantum Computation

• Peter Zoller: Control of Quantum Systems

• Bertrand Halperin: Quantum Condensed Matter

• Howard Georgi: Particles and Fields

• Joseph Polchinski: Quantum Gravity and String Theory

• David Gross: Conclusions

The following sections are included:

• Address by the Chair of the Conference: David Gross

• Address by the Director of the International Solvay Institutes: Marc Henneaux