# Presentation: 063376

## 	  CLOSING 

- 	 THOUGHTS

- David Gross
- KITP/UCSB
- COSMO-02

- THANKS Evalyn, John and Sean FOR A CLASSY CONFERENCE

## ENVY

- This is truly a golden age of cosmology

- Beautiful observations
- The emergence of a “standard model”

## m

- m

- 

- 

- 

**Supernova**

**CMB**

- Large Scale Structure

- 

- m

- total

- n=1.02

- h=.7

- + 11 more parameters

- A marvelous
- STANDARD MODEL

## 	THE STANDARD MODEL

- SRTRENGTH

- OF
- FORCE

- ENERGY

- ev

- UNIFICATION

- STRONG

- WEAK

- ELECTRO

- ev

- Present day observation

- GRAVITY

- Planck Scale

## STRONG

**STRONG**

**COUPL I NG**

## Slide 6

## Slide 7

## Slide 8

##  THE STANDARD MODEL

- SRTRENGTH

- OF
- FORCE

- ENERGY

- ev

- LHC

- UNIFICATION

- STRONG

- WEAK

- ELECTRO

- ev

- Present day observation

- GRAVITY

- Planck Scale

- Supersymmetry

## Astrophysics is a major consumer of theory

- Quantum Mechanics     spectroscopy, stellar structure ...

- General Relativity        cosmic expansion,....

- Nuclear Physics           stellar structure, nucleosynthesis,...

- Particle Physics            baryogenesis, inflation,...

- As an observational (non-laboratory) science
- Astrophysics requires good theoretical understanding
- in  order to interpret observation

## Has Astrophysical observation discovered 

- new fundamental physics ?

- The measurement of planetary motion (Kepler)

- Newton’s Theory of Gravity

- More recently?

- Testing ground for fundamental physics
- General Relativity, Nuclear fusion, Neutrino physics
- Standard Model, Constraints on new physics

## ?????

- new fundamental physics ?

- The measurement of planetary motion (Kepler)

- Newton’s Theory of Gravity

- More recently?

- Dark Matter

- Dark Energy
- 

- Many plausible particle
- Physics candidates

## 		Theory Space

***PARTICLE***

- GN

- h

- c

**CONDENSED   MATTER**

**STRING THEORY**

**& Cosmology**

- 		Theory Space

## ?

- WILL STRING THEORY YIELD THE PRINCIPLE THAT
-  DETERMINES THE HISTORY OF THE UNIVERSE?

-   t

- 	TIME BEGINS
- Fix uniquely the initial condition, the wave function of the universe at t=0

## ?

- WILL STRING THEORY YIELD THE PRINCIPLE THAT
-  DETERMINES THE HISTORY OF THE UNIVERSE?

-   t

- 	TIME GOES BACK FOREVER
- Cyclic or bouncing universe that passes smoothly through a “singularity” at t=0

## ?

- WILL STRING THEORY YIELD THE PRINCIPLE THAT
-  DETERMINES THE HISTORY OF THE UNIVERSE?

-   t

- 	AT THE BEGINNING TIME HAS NO MEANING
- Time is an emergent concept

##        SPACE-TIME IS DOOMED ?

- IIA Theory in 10-d		M-theory in 11-d
-              

- String compactified on  M1

- String compactified on  M2

-    ???

**       ****SPACE-TIME IS DOOMED ?**

-   CHANGE THE NUMBER OF SPATIAL DIMENSIONS

- IN STRING THEORY WE CAN

-   CONTINUOUSLY TEAR THE FABRIC OF SPACE

## =

- R

- DUAL  TO

- 1/R

- x

- STRING MICROSCOPE

- Strings expand at high energy

**The String Uncertainty Principle**

- 	 **IN STRING THEORY WE CANNOT**
-   Probe arbitrarily small distances

-   Squeeze spatial volumes to zero size

## WE HAVE HINTS THAT SPACE-TIME CAN BE

**R****EPLACED**

- Space (& time?) are emergent concepts

## WE HAVE HINTS THAT SPACE-TIME CAN BE

**R****EPLACED**

**H****OLOGRAPICALLY ****R****EPRESENTED**

- The fundamental degrees of freedom
- of a consistent theory of gravity
- reside on the boundary of space time

- e.g. M(atrix) Theory

## WE HAVE HINTS THAT SPACE-TIME CAN BE

**R****EPLACED**

**H****OLOGRAPICALLY ****R****EPRESENTED**

- e.g. M(atrix) Theory

- e.g. AdS/CFT

## WE HAVE HINTS THAT SPACE-TIME CAN BE

**R****EPLACED**

**H****OLOGRAPICALLY ****R****EPRESENTED**

**By convention there is color,**
**by convention sweetness,**
**by convention bitterness,**
**but in reality there are atoms and space.**
- Democritus (400 B.C.)

- e.g. M(atrix) Theory

- e.g. AdS/CFT

## WE HAVE HINTS THAT SPACE-TIME CAN BE

**R****EPLACED**

**H****OLOGRAPICALLY ****R****EPRESENTED**

**W****e**** ****are convinced that**
***	******“ ******by convention there is space, ***
***             ******by convention there is time,***
***          ******but in reality there is ....”***

- e.g. M(atrix) Theory

- e.g. AdS/CFT

## PREDICTIONS

- Experimental Cosmology will provide increasingly precise
- tests of the standard model, Dark matter will be identified

- Theorists will split

- Structure Formation

- Early Cosmology

- Particle, string, brane
- phenomenology

- Fundamental string theory

## IT SHOULD ALL BE CLEAR

- BY COSMO -    03

- THANKS AGAIN FOR A
- 		CLASSY CONFERENCE

## IT SHOULD ALL BE CLEAR

- BY COSMO -    03

- 21

- THANKS AGAIN FOR A
- 		CLASSY CONFERENCE