UCSB COMPUTER SCIENCE DEPARTMENT PRESENTS:
WEDNESDAY, FEBRUARY 11, 2009
3:30 – 4:30
Engineering Sciences Building, Room 1001
HOST: OMER EGECIOGLU
SPEAKER: James Hartle
Professor Emeritus, Department of Physics, UCSB
Title: Is Physics Computable?
Physical theories are usually assumed to predict computable numbers –
numbers for which an algorithm exists to compute them to any desired
accuracy. But what would science be like if physics predicted
non-computable numbers? This talk will address such questions in the
context of quantum cosmology – the search for a theory of the universe’s
initial quantum state. More specific implications of general relativity
for limits on computation will also be discussed. What is meant by
computation time in a curved spacetime where computers traveling on
different paths can complete different numbers of computational steps?
Do black holes provide a way of speeding up computation enough to evade
the halting problem? The author knows of no engineering application for
the answers to these questions, and will correspondingly aim at a simple
presentation with few technical details.
Prof. Hartle is one of the founders of the Kavli Institute for
Theoretical Physics (KITP) at UCSB. He is the developer of the
Hartle-Hawking wave-function of the Universe, and the 2009 recipient of
the American Physical Society’s Einstein Prize.