Natuurkundig Gezelschap te Utrecht

Jaarprogramma 2006-2007 | Home


Dinsdag 6 februari 2007
prof.dr. R. Loll (Instituut Theoretische Fysica, UU)

Quantum Structure of Spacetime: a Sneak Preview

What does empty spacetime look like on the very smallest scale? This fascinating and age-old question still awaits resolution by a quantum formulation of Einstein’s theory of General Relativity. Although qualitative pictures of a fluctuating “quantum foam” at this tiny Planck scale have been around for almost 50 years, we still lack a quantitative microscopic model which at the same time reproduces our ordinary four-dimensional spacetime on large scales.

I will describe the intriguing new view of spacetime that emerges from assembling sub-Planckian geometric building blocks into a finite-size universe. The underlying method of Causal Dynamical Triangulations is elegant and minimalist, and based on a quantum superposition principle and a microcausality postulate.

The building rules of this dynamical model of quantum gravity are completely explicit and have enabled us to create a piece of quantum universe on a desktop computer and study some of its physical properties. Taking a closer look at its microscopic geometry reveals an entirely non-classical, fractal space of dimension two instead of the expected four, offering a tantalizing glimpse of the quantum structure of spacetime beyond the world view of 20th century physics.

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De vergaderingen worden gehouden in de grote collegezaal van het Gebouw voor Aardwetenschappen, De Uithof (te bereiken via de ingang van het Buys Ballotlaboratorium, Princetonplein 5). De aanvang is telkens om 20.00 uur, de vergaderingen duren inclusief een pauze tot uiterlijk 22.00 uur.