Physics
drorzel | October 31, 2008The high-energy physics blogosphere (well, two blogs worth) is abuzz this morning with the news that the CDF collaboration has seen something in collisions producing multiple muons (a muon is sort of like an electron, only heavier). You can get more from Tommaso Dorigo and Peter Woit.
What they're really seeing is not entirely clear. They see more of these collisions that produce multiple muons than they can explain with the Standard Model, but it's not clear what that means at this point. It could be some exotic particle, or it could just be a new and interesting background effect in their…
drorzel | October 30, 2008Steinn responds to yesterday's post about his comments about science blogging. I'm going to continue the tradition of responding here, rather than in his comments, because, well, I need something to post today.
He concedes that outreach is a worthy purpose of blogging, but continues to be concerned about blogging as a tool for more traditional science:
Is blogging enabling collaborations?
Is blogging leading to new initiatives? New directions in research? Providing connectivity which would not otherwise have happened? Conveying information that is important to research and otherwise hard to…
rallain | October 29, 2008I don't need to explain that I think the Mythbusters are awesome (do I?). I just finished watching their latest episode. In it, they tested the scene from Indiana Jones and the Last Crusade where Indy puts a flag pole in another motorcycle wheel. The result in the movie is that the motorcycle goes flipping in the air. I have no problems with their test - it seems like they did a decent job. However, in the end, Adam says something to the effect:
*"Look how high that bike went. It took a lot of energy. There is no way that energy could come from this stick I shove into the wheel."*
I am…
drorzel | October 29, 2008Last week, I wrote about ion traps as a possible quantum computing platform, which are probably the best established of the candidate technologies. This week, I'll talk about something more speculative, but closer to my own areas of research: neutral atoms in optical lattices.
This is a newer area, which pretty much starts with a proposal in 1999. There are a bunch of different variants of the idea, and what follows will be pretty general.
What's the system? Optical lattices use the interaction between atoms and a standing wave of light to produce a periodic array of wells in which individual…
drorzel | October 29, 2008Steinn asks a provocative question:
has science blogging done any good?
I can think of science policy issues where blogging has made a contribution, and the general spread of information and communication done by blogs has probably had some impact, but has any actual science been directly impacted by blogs, or discussion on blogs? I am hard pressed to think of concrete examples.
I think this is a badly framed question. That is, I think it's a mistake to define "good" for science to exclude science policy questions and the general spread of information. It's a very common mistake, mind, and…
pontiff | October 28, 2008
I've spent the last two days in the San Francisco bay area visiting first Stanford and then Berkeley.
Highlights of the trip included:
Talking to Jelena Vuckovic about the work she and her group have been performing on strongly coupling photonic crystals to quantum dots.
Talking to Thaddeus Ladd and Yoshihisa Yamamoto about their work on ultrafast pulses for controlling electron spin which appears in Nature Physics. Picosecond single qubit gates, mmmm.
Talking with Vaughan Pratt. I did not tell him that I am teaching his (and Knuth and Morris') algorithm this Friday! Oh, and I shook…
drorzel | October 28, 2008Over at Dot Physics (which might be the best physics blog in the world at the moment), Rhett Allain has a pair of posts exploring the physics of Fantastic Contraption.
The posts don't really lend themselves to excerpting, so you need to go over there and read them, but I think they're brilliant, and deserve better than just a spot in a links dump. These may be the best example of the scientific mindset that you'll find on a blog.
What he does is to set out to determine whether the world of Fantastic Contraption obeys a consistent set of physical laws, by coming up with ingenious experiments…
rallain | October 28, 2008Yes, I did some experiments with [Fantastic Contraption](http://fantasticcontraption.com/) ([Water sticks in Fantastic Contraption](http://blog.dotphys.net/2008/10/water-stick-springs-in-fantastic-contra…), [Torque from rotating balls in FC](http://blog.dotphys.net/2008/10/torque-produced-by-balls-in-fantastic-c…), [Basic stuff in FC](http://blog.dotphys.net/2008/10/physics-of-fantastic-contraption-i/)). But apparently, there is a wiki with some of the answers:
[List of physics parameters for Fantastic Contraption](http://fc.therisenrealm.com/wiki/List_of_physics_parameters) I assume these…
rallain | October 28, 2008Here is what is cool about [Fantastic Contraption](http://fantasticcontraption.com/) - it's like a whole new world, a world ready for exploring. I am Newton, and I can see if this world follows the models that I propose.
In this post, I am going to explore the elastic nature of the "water-sticks". If you have played fantastic contraption, I am sure you noticed that the water-sticks are springy. How does these springy sticks work? Are they just like the springs we have in the real world? An excellent model for springs in the real world is Hooke's law. It says the force exerted by a…
rallain | October 26, 2008The fun part about exploring the physics of [Fantastic Contraption](http://fantasticcontraption.com/) is coming up with new setups to test ideas. Torque is not too difficult to set up. Here is what I did:
In this setup, I have a "turning ball" with a wood stick attached to the side. I increased the length of the stick until the ball does not turn. At this point, the torque from the gravitational force on the stick is equal to the torque from the ball. I can use [Tracker Video Analysis](http://www.…
rallain | October 23, 2008One of my students showed me this game, [Fantastic Contraption](http://fantasticcontraption.com/). The basic idea is to use a couple of different "machine" parts to build something that will move an object into a target area. Not a bad game. But what do I do when I look at a game? I think - hey! I wonder what kind of physics this "world" uses. This is very similar to [my analysis of the game Line Rider](http://scienceblogs.com/dotphysics/2008/09/the-physics-of-linerider/) except completely different.
Fantastic Contraption gives the unique opportunity to build whatever you want. This…
drorzel | October 23, 2008Doug Natelson is thinking about fortuitous physics, inspired by some solid state examples:
Every now and then you stumble across a piece of physics, some detail about how the universe works, that is extremely lucky in some sense. For example, it's very convenient that Si is a great semiconductor, and at the same time SiO2 is an incredibly good insulator - in terms of the electric field that it can sustain before breakdown, SiO2 is about as good as it gets.
From my own field of physics, I would suggest the rubidium atom. Rubidium isn't a substance you run across every day, and that's a Good…
rallain | October 23, 2008I am sorry to point this out, but I can't help it. My kids watch this show "Fetch with Ruff Ruffman". It's mostly an ok kids show. However, there was a problem. In one episode, some kids were in the desert and measuring temperature with (they said it several times and it was even a quiz question at the end) - a LASER. Here is the device they used:
This is an infrared thermometer with a LASER aiming system. The laser is only there to help you aim. The temperature is determined by measuring the infrared…
drorzel | October 22, 2008Another question from a generous donor, in this case Natalie, who asks:
As for my question, how about "who is your favorite author, and why?" or, if you'd rather, "what's your favorite book, and why?"
This is a difficult question, because it's subject to a sort of quantum projection noise. That is, my "favorite book" and "favorite author" exist in a sort of quantum superposition of all the various possibilities. When someone asks, I can give an answer and either the wavefunction collapses to that value at that instant, or the universe splits into many parallel universes, each with its own…
pontiff | October 22, 2008The universe doesn't always operate the way we want it to. No, I'm not talking about the stock market (unless you've been short lately), I'm talking about the role of error in logical deterministic systems! When you zoom down far enough into any computing device you'll see that its constituent components don't behave in a completely digital manner and all sorts of crazy random crap (technical term) is going on. Yet, on a larger scale, digital logical can and does emerge.
Today heading to work in the early dawn I was pondering what all of this meant for our notion of reality.
Some of the…
drorzel | October 22, 2008Some time back, I wrote about what you need to make a quantum computer. Given that it's election season, I thought I'd revisit the topic by looking in detail at the candidate technologies for quantum computing.
The first up is Ion Trap Quantum Computing, probably the most well-established of any of the candidates. The field really starts with Dave Wineland's group at NIST, though there is outstanding stuff being done by Chris Monroe at Maryland, and a host of others.
So, how do they stack up? Here are the facts about ion traps as a quantum computing system:
What's the system? Ion traps are,…
rallain | October 21, 2008[In a previous post, I talked about numerical calculations](http://scienceblogs.com/dotphysics/2008/10/basics-numerical-calculation…). The basic idea is to use the momentum principle and the following "recipe":
Update the position of the particle
Update the momentum of the particle
Update the force on the particle
Looks great, right? Well, it mostly is great. I want to give a couple of pointers about the last step, update the force on the particle. How and when can you do this? Really, in numerical calculations, you will see two types of forces:
Forces that you can calculate: That…
rallain | October 21, 2008I know I should just let go, but this is what makes me, me. I understand that there are terms in physics (like for instance 'pressure') that are used in all sorts of ways in common language. The problem is when someone tries to explain something scientifically and misuses a word. Pressure means something. It is the average force per area due to collisions of a gas or liquid on a surface. Really, you can see a good animation of this, I have a link and explanation when [I talked about MythBuster's Lead Balloon](http://scienceblogs.com/dotphysics/2008/09/mythbusters-how-small-could-…).
So,…
rallain | October 20, 2008**Pre Reqs:** [What is a Force](http://scienceblogs.com/dotphysics/2008/09/basics-what-is-a-force.php)
[Previously, I talked about the momentum principle](http://scienceblogs.com/dotphysics/2008/10/basics-forces-and-the-moment…). Very useful and very fundamental idea. The other big (and useful) idea in introductory physics is the work-energy theorem. Really, with work-energy and momentum principle, you will be like a Jedi with a lightsaber and The Force - extremely powerful.
Well, what is work? What is energy? How are they related? In [another post, I talked about energy.](http://…
rallain | October 16, 2008Maybe you know I like numerical calculations, well I do. I think they are swell. [VPython](http://vpython.org) is my tool of choice. In the post [Basics: Numerical Calculations](http://scienceblogs.com/dotphysics/2008/10/basics-numerical-calculation…) I used vpython and excel to do something simple. I will do that again today (in that this problem could also be solved analytically). However, there is one big difference. This problem has a non-constant forces. Suppose I have a mass that is connected by a spring to a wall. This mass-spring is sitting on a table with no friction.
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