Recent content by Turtle492

Hi, I wanted to explain quantum tunnelling to people with no scientific background - I've come up with the following analogy, but I'm only a physics undergrad and I'm not sure if it's a good enough analogy. I can do the maths behind tunnelling but it's just the concept I'm trying to get across...

I'm a second year physics undergraduate and am currently taking part in a summer studentship programme where I spend a few weeks working in the cold atoms lab at my university. I've been looking into sub-doppler cooling, and one text in particular keeps referring to 'light-shifted ground states'...

OK, I think I understand. Thanks a lot, that's really helpful.

So if you measure Lx and L2, say, then it will be in an eigenstate that is common to both of them? What if I measure Lz and L2 and I get the same value for L2 as I did when I was using Lx, would it not then be in the same eigenstate for L2 as it was before, and is now sharing that one with Lz...

Hi, I'm a second year physics undergrad currently revising quantum mechanics, and I came across a phrase about angular momentum which has confused me, so I was wondering if anyone could help. We looked at different components of angular momentum (in Cartesian) and decided that they did not...

So if we had a magnetic field in the z direction, the spin in the x and y directions can change in time but the z component can't? Also, does saying 'we know the initial spin state of the particle' mean it must be in an eigenstate, or does it just mean we know how the eigenstates combine with...

We've been covering quantum spin lately in lectures and I'm a little confused about the time-dependence of it. Basically what I want to know is - if you know that a particle (let's say an electron) is in a certain spin state (say it's spin-up) at one point, if you come back and look at it...

Surely then the invention of a suitable measuring device would make it in principle possible to find out which slit a photon went through? Just having one in the same room means that an observation *could* have taken place, what is the difference to the particle of whether you couldn't be...

OK so having re-read this thread and tried to explain it to a friend, it seems that a recurring theme is that 'refined' sugar is bad for you, much more so than naturally occurring sugars. So I was wondering if someone could explain to me what is actually meant by the term 'refined'. Why is...

I don't know anything at all about mitosis, or chromosomes for that matter, but sounds to me like it's just easier to show you one 'example' pair of chromosomes than to do all 46 of them. They probably wouldn't all fit in the diagram, or if they did they'd be so small you wouldn't be able to see...

OK so even if it's processed sugar, why does processing it make it bad for you? And in what WAY is it bad for you?

So say you were fairly fit and healthy and weren't putting on weight, is it OK to pretty much eat as much sugar as you want as long as you're eating enough of all the other nutrients you need as well?

These days there's a lot of hype about cutting down on sugar in your diet, and there's all those GDAs and advice about how to reduce your sugar intake, etc, but I can't really find much information about why sugar is bad for you. It seems, from what I've found online, that pretty much the only...

Thanks for the reply, although I'm not sure it's temperature related. I could understand it if the condensation was just caused by going from a hot place to a cold place, but this seems to a be a day-to-day thing. I wake up in the morning and either it's steamed up or it isn't, and it stays that...

I have a question about my watch which has been bugging me for a little while, and I was wondering if anyone could enlighten me as to the physics behind it. One day a while back I went out for a run in the rain and some water got into my watch, behind the glass. I only noticed because it had...