Gheorghe Curelet-Balan Blog

Thursday, December 06, 2007

Bring more chairs please!

This is what I was hearing before the beginning of yesterday's PI lecture. And chairs were continuously added (getting in the way of my camera that was looking for a perfect snapshot) to accommodate the latecomers or those that weren't lucky enough to get tickets. The front seats were reserved for special guests among whom I spotted Raymond Laflamme, Lee Smolin and other PI researchers.

Right before the beginning of the lecture a very special guest joined the audience. It was Mike Lazaridis, the father of PI, that was wearing a nice University of Waterloo leather jacket.

And so, the overloaded WCI lecture room was ready to sail into discovering the unknown world of information fundamentals. And what discovery it was...

Bob McDonald, the host of CBC's Quirks & Quarks was the captain of this ship (someone had to keep it on course and guard the order just in case the debates became too heated).

Bob started the debate by stating that physicists see information differently than the rest of us. They are interested to know what information is made of. For example while most of us after taking a bite of an apple see a BITE, the physicists see a BIT, and he paused... and the room started to laugh. Millions of bits, he continued, that give the shape, color and texture of the apple.

That was a good introduction for Bob to ask the panelists how do they define the information.

Information is everything, answered Seth Lloyd shortly. Then he elaborated the idea that through the works of Maxwell, Boltzmann and others, physicists have defined the information (in their effort to quantify entropy) around 150 years ago, well before information age was born.

Then, Leonard Susskind defined information as predicting of what is next. And he used the example of a bathtub of water. Knowing all the information about each molecule of water (velocity, position, etc.) allows you to predict what will happen next. "That's a lot of information" said Bob. And he continued with the question of how close are we to know all that information. Leonard replied calmly that before getting into the bathtub he knows at least its temperature and the volume :)

Tony Leggett then defined the information as being about something and embedded into something. He used the example of a map. Leonard disagreed that the information about Waterloo being north of Kitchener is on the map since it is about their physical position on the Earth's surface.

This small debate created the opportunity for Bob to ask if there is any information that is not physical? And the answers were yes, no, yes, no.

Then Chris Fucks used an example from the probability theories to make the point that there is a difference between the world as it is and what someone knows about it.

And so it went for the rest of the panel discussions. What a nice way to end a year full of great public lectures. And it looks like the next year will be greater.

Thank you PI for illuminating us!

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