I'm at a physics conference this week

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Well, I may not be able to post on WP this week as much as I normally do. Right now, I'm sitting in the lounge of Pumula Hotel in Durban. I'm here completely alone and didn't come with anyone because I'm here at a physics conference. This time I'm even giving a presentation on my PhD work.

Sounds fun and interesting. Hope your presentation goes well, what is it about?

Thanks TallyMan. My presentation is about quantum entanglement and how it affects causality in relativistic quantum measurements.

Quantum entanglement is quite fascinating. I've not heard of it in a relativistic context before, except maybe if two entangled photons part at the speed of light and when one interacts with something it collapses the wave function of the other despite the huge separation between the particles. The details and maths are somewhat beyond me nowadays but I found the subject very interesting when I was a science student many years ago.

Yes, the interesting thing is that quantum entanglement doesn't actually violate causality because despite the apparent contradiction in the EPR paradox of information appearing to travel faster than light between the entangled particles, there is actually no information exchanged between them. Thus, special relativity remains perfectly safe even as far as quantum entanglement is concerned, there is actually no information traveling faster than light.

I'd heard of people trying to (theoretically) transfer information faster than light by manipulating one of the entangled particles but theoretical attempts have failed... apparently (if memory serves correctly) by detecting the (polarity or other entangled property) they essentially change an unknown state to another unknown state. So while one entangled particle influences the other particle at the same moment there is no way to use this to transfer information faster than the speed of light.

That reminds me of something related. Wasn't there a breakthrough fairly recently that allowed a quantum state to be "gently probed" somehow without collapsing it but being able to infer information about its state nonetheless? Can't remember where I read the article or the details now.

It is a really fascinating field and shows that our common, every day notions of reality completely fail when the circumstances are outside our normal scope regarding objects with sizes and velocities outside of normal human experience. I remember as a student one of my physics lecturers showing a (logarithmic based) graph of distances ranging from the smallest (Planck) length to the size of the universe against velocities from zero to the speed of light. Human "common sense" ideas about reality only covered a tiny square on this graph. Quantum physics and relativity covering the rest of it. I look forward to the day when a unified theory puts the two together seamlessly.

Well, I've given my presentation earlier today and I'm going back home tomorrow.