Last time, I showed you how you could construct a photon, a light particle, in a configuration of mirrors called a ring cavity. This time I’ll show you that sometimes, you can’t make just one particle—they only come in pairs. And sometimes, the notion of a particle doesn’t make any sense at all. (This post relies heavily on last week’s post, so if you haven’t read that, I recommend you do so.) Disclaimer: What I’m about to describe is only the simplest case, and I make simplifications for the sake of exposition. It is possible to capture and manipulate
Physics
explanatory articles on physics
Physics / Quantum Mechanics / Science And Math
What’s in a Particle?
If you’ve read or heard anything about quantum mechanics, you’ve heard the phrase “particle-wave duality.” The common wisdom is that this means that particles sometimes behave like waves and sometimes behave like particles. And although this is right, it’s a bit misleading. The truth is: Everything is always a wave. It’s just that waves can be made to behave like particles. To see what I mean, let’s actually show how one can make a set of waves behave like a particle. Specifically, let’s show how a set of light waves can be made to behave like a photon, a light particle.
Astrophysics / Physics / Science And Math
Pope Francis says Evolution and the Big Bang are Compatible with Catholicism
You’ve probably heard, the news. Pope Francis has announced that Big Bang cosmology and evolutionary theory are compatible with Catholicism and “may even be required.” This is, of course, wonderful news. It’s evidence that science and religion are not necessarily incompatible and that people of faith can modify their beliefs based on the evidence around them. But it should have been this way all along. Indeed, it originally _was_ this way. One of the people who developed Big Bang cosmology, Monseigneur Georges Henri Joseph Édouard Lemaître was a catholic priest who believed that his studies of physics brought him
Astrophysics / Physics / Relativity / etc.
What Space Projects Excite Me: Multi-Messenger Astronomy
A few weeks ago, awesome blogger and space advocate Zain Husain asked me to contribute to a roundup post he wrote. He contacted a bunch of people (most of them much more prestigious than me) and asked them one question: What NASA or space project are you most excited about and why? You can (and should) read everybody’s response to Zain’s question on his blog, here. However, I wanted to expand on part of my answer and tell you why I’m excited about multi-messenger astronomy. Supernova Supernova It all starts with the title image above. That’s an image of
Computer Related / Electronics / logic / etc.
Non-Digital Computers
Non-Digital Computers This is the last installment of my many-part series on computers. Last time we used the notion of a Turing machine to define what a computer is. We discovered something surprising: that not all computers need to be digital, or even electronic! A computer can be mechanical, made of dominoes, or even just a rules system in a card game. To give you of a flavor of how inclusive the definition of a computer really is, I’ll now give you a whirlwind tour of some notable examples of non-digital computers. The Antikythera Mechanism In April of 1900,
Electronics / Physics / Science And Math
Flip-Flops and the Art of Computer Memory
It’s a poor sort of memory that only works backwards. ~The White Queen to Alice (Lewis Carroll, Through the Looking Glass) This is the fifth part in my multi-part series on how computers work. Computers are thinking machines, and the first four parts of my series have been on how we teach computers to think. But all of this logic, electronic or otherwise, is useless unless our computers can remember what they did. After logicking something out, a computer needs to remember the result of all that logicking! In this post, I describe how to use the logic gates
Computer Related / Electronics / logic / etc.
The Boolean Circuit and Electronic Logic, Part 2
If the presence of electricity can be made visible in any part of the circuit, I see no reason why intelligence may not be transmitted instantaneously by electricity. ~Samuel Morse This is the fourth part in my multi-part series on how computers work. Computers are thinking machines, but they can’t do this on their own. We need to teach them how to think. And for this, we need a language of logic. In the first part of the series, I introduced this language of logic, Boolean algebra. In the second part, I described how to formulate complex logical statements
Computer Related / Condensed Matter / History / etc.
The Boolean Circuit and Electronic Logic, Part 1
Living in a vacuum sucks. ~Adrienne E. Gusoff This is the third part in my multi-part series on how computers work. Computers are thinking machines, but they can’t do this on their own. We need to teach them how to think. And for this, we need a language of logic. In the first part of the series, I introduced this language of logic, Boolean algebra. In the second part, I described how to formulate complex logical statements using Boolean algebra. Now, in part three, I lay the groundwork for how we can implement simple Boolean logic using electronics. In
Astrophysics / Physics / Science And Math
How Planets Form
The Heavenly Spheres make music for us, The Holy Twelve dance with us, All things join in the dance! Ye who dance not, know not what we are knowing ~Gustav Holst By the sweat of your brow you will eat your food until you return to the ground, since from it you were taken; for dust you are and to dust you will return. ~Genesis 3:19 Many months ago, Richard Green posted an article on Google+ that described how life on a toroidal planet would work. The discussion in the comments eventually led to speculation as to whether or
Condensed Matter / optics / Physics / etc.
The Graphene Electro-Optic Modulator
Say we have a beam of light—maybe we made it with a laser. We’d like be able to change the intensity of the beam so that we can alternately brighten and dim it. Moreover, we’d like to be able to do so quickly. Physically blocking and unblocking the beam just isn’t fast enough. So what do we do? The solution is to make an electric switch so we can change how the light behaves via electrical signals. This is an electro-optic modulator (EOM). Two weeks ago, I introduced graphene to you all. And last week, I described some of