Category Archives: Misc

Poll Results, and What’s Next

I’ll leave last week’s poll up a while longer as more votes trickle in, but the overall pattern (beyond “Zipflike“) is pretty clear.

From pretty early on, most requests were for more explanations of QFT, gravity, and string theory concepts, with amplitudes content a clear second. This is something I can definitely do more of: I haven’t had much inspiration for interesting pieces of this sort recently, but it’s something I can ramp up in future.

I suspect that many of the people voting for more QFT and more amplitudes content were also interested in something else, though: more physics news. Xezlec mentioned that with Résonaances and Of Particular Significance quiet, there’s an open niche for vaguely reasonable people blogging about physics.

The truth is, I didn’t think of adding a “more physics news” option to the poll. I’m not a great source of news: not being a phenomenologist, I don’t keep up with the latest experimental results, and since my sub-field is small and insular I’m not always aware of the latest thing Witten or Maldacena is working on.

For an example of the former: recently, various LHC teams presented results at the Moriond and Aspen conferences, with no new evidence of supersymmetry in the data they’ve gathered thus far. This triggered concessions on several bets about SUSY (including an amusingly awkward conversation about how to pay one of them).

And I only know about that because other bloggers talked about it.

So I’m not going to be a reliable source of physics news.

With that said, knowing there’s a sizable number of people interested in this kind of thing is helpful. I’ve definitely had times when I saw something I found interesting, but wasn’t sure if my audience would care. (For example, recently there’s been some substantial progress on the problem that gave this blog its name.) Now that I know some of you are interested, I’ll err on the side of posting about these kinds of things.

“What’s it like to be a physicist” and science popularization were both consistently third and fourth in the poll, switching back and forth as more votes came in. This tells me that while many of you want more technical content, there are still people interested in pieces aimed to a broader audience, so I won’t abandon those.

The other topics were fairly close together, with the more “news-y” ones (astrophysics/cosmology and criticism of bad science coverage) beating the less “news-y” ones. This also supports my guess that people were looking for a “more physics news” option. A few people even voted for “more arguments”, which was really more of a joke topic: getting into arguments with other bloggers tends to bring in readers, but it’s not something I ever plan to do intentionally.

So, what’s next? I’ll explain more quantum field theory, talk more about interesting progress in amplitudes, and mention news when I come across it, trusting you guys to find it interesting. I’ll keep up with the low-level stuff, and with trying to humanize physics, to get the public to understand what being a physicist is all about. And I’ll think about some of the specific suggestions you gave: I’m always looking for good post ideas.

New Poll: What Would You Like to See More Of?

It’s been a while since I last polled you guys. Back then, I was curious what sorts of backgrounds my readers had. In the end, roughly half of you had some serious background in high-energy physics, while the other half had seen some physics, but not a lot.

This time, I’d like to know what sort of content you want to see. WordPress tells me how well an individual post does, but there isn’t much of a pattern to my best-performing posts beyond the vagaries of whose attention they grab. That’s why I’m asking you what you want to see more of. I’ve split things into vague categories. Feel free to vote for as many as you like, and let me know in the comments if there’s something I missed.

The Way to a Mathematician’s Heart Is through a Pi

Want to win over a mathematician? Bake them a pi.

Of course, presentation counts. You can’t just pour a spew of digits.

1200px-pi_tau_digit_runs-svg

If you have to, at least season it with 9’s

Ideally, you’ve baked your pi at home, in a comfortable physical theory. You lay out a graph to give it structure, then wrap it in algebraic curves before baking under an integration.

(Sometimes you can skip this part. My mathematician will happily eat graphs and ignore the pi.)

At this point, if your motives are pure (or at least mixed Tate), you have your pi. To make it more interesting, be sure to pair with a well-aged Riemann zeta value. With the right preparation, you can achieve a truly cosmic pi.

whirled-pies-54

Fine, that last joke was a bit of a stretch. Hope you had a fun pi day!

Valentine’s Day Physics Poem 2017

It’s that time of year again! Valentine’s Day was this week, so to continue this blog’s tradition it’s time for me to post one of my physics poems. I wrote this back before I fully understood quantum field theory, so you’ll have to excuse any inaccuracies in the metaphor (at least on the physics side 😉 ).

 

Perturbation Theory II – Going in Loops

 

In order to interact, two particles must collide.

But a particle is a small thing, moving in its own circles, covering little space in its lonely life.

So we will never interact.

 

But particles emit bosons,

Tiny messengers of force,

Tendrils of interaction.

When these find us,

As they sometimes do,

We can interact.

 

But a boson is a small thing, moving in its own circles, covering little space in its lonely life.

So we will never interact.

 

But each boson has its own retinue,

Particles and their bosons in turn,

Spawned from its self-energy, uncertainty in its own nature,

Each, unobserved, with infinite possibilities.

 

And to compensate for these infinities

The charged nature of our naked selves

Must in turn be infinitely repressed.

 

So perhaps interaction would still be understandable

For those with simple repressions,

Matching constraints.

 

But we are not such people.

Complicated beings, we spin and twirl.

We hide our charge behind an infinity of possible terms,

So we can never know

If we will interact.

 

But perhaps we are not simply isolated points.

Perhaps we have extension,

Dimension,

Reach, beyond the confines of zero-dimensional selves.

And with that reach

Perhaps we can understand.

Perhaps

We can interact.

PSI Winter School 2017

It’s that time of year again! Perimeter Scholars International, Perimeter’s Master’s program in theoretical physics, is holding its Winter School up in Ontario’s copious backwoods.

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Ominous antlered snowmen included

Like last year, the students are spending mornings and evenings doing research supervised by PI grad students, postdocs, and faculty, and the afternoons on a variety of winter activities, including skiing and snowshoeing.

Last year, my group worked on the “POPE”, a proposal by Basso, Sever, and Vieira, and we ended up getting a paper out of it. This year, I’ve teamed up with Freddy Cachazo on a gravity-related project. We’ve got a group of enthusiastic students and are making decent progress, I’ll have more to say about it next week.

Have You Given Your Kids “The Talk”?

If you haven’t seen it yet, I recommend reading this delightful collaboration between Scott Aaronson (of Shtetl-Optimized) and Zach Weinersmith (of Saturday Morning Breakfast Cereal). As explanations of a concept beyond the standard popular accounts go, this one is pretty high quality, correcting some common misconceptions about quantum computing.

I especially liked the following exchange:

ontology

I’ve complained before about people trying to apply ontology to physics, and I think this gets at the root of one of my objections.

People tend to think that the world should be describable with words. From that perspective, mathematics is just a particular tool, a system we’ve created. If you look at the world in that way, mathematics looks unreasonably effective: it’s ability to describe the real world seems like a miraculous coincidence.

Mathematics isn’t just one tool though, or just one system. It’s all of them: not just numbers and equations, but knots and logic and everything else. Deep down, mathematics is just a collection of all the ways we’ve found to state things precisely.

Because of that, it shouldn’t surprise you that we “put complex numbers in our ontologies”. Complex numbers are just one way we’ve found to make precise statements about the world, one that comes in handy when talking about quantum mechanics. There doesn’t need to be a “correct” description in words: the math is already stating things as precisely as we know how.

That doesn’t mean that ontology is a useless project. It’s worthwhile to develop new ways of talking about things. I can understand the goal of building up a philosophical language powerful enough to describe the world in terms of words, and if such a language was successful it might well inspire us to ask new scientific questions.

But it’s crucial to remember that there’s real work to be done there. There’s no guarantee that the project will work, that words will end up sufficient. When you put aside our best tools to make precise statements, you’re handicapping yourself, making the problem harder than it needed to be. It’s your responsibility to make sure you’re getting something worthwhile out of it.

arXiv vs. snarXiv: Can You Tell the Difference?

Have you ever played arXiv vs snarXiv?

arXiv is a preprint repository: it’s where we physicists put our papers before they’re published to journals.

snarXiv is…well..sound it out.

A creation of David Simmons-Duffin, snarXiv randomly generates titles and abstracts out of trendy arXiv buzzwords. It’s designed so that the papers on it look almost plausible…until you take a closer look, anyway.

Hence the game, arXiv vs snarXiv. Given just the titles of two papers, can you figure out which one is real, and which is fake?

I played arXiv vs snarXiv for a bit today, waiting for some code to run. Out of twenty questions, I only got two wrong.

Sometimes, it was fairly clear which paper was fake because snarXiv overreached. By trying to pile on too many buzzwords, it ended up with a title that repeated itself, or didn’t quite work grammatically.

Other times, I had to use some actual physics knowledge. Usually, this meant noticing when a title tied together unrelated areas in an implausible way. When a title claims to tie obscure mathematical concepts from string theory to a concrete problem in astronomy, it’s pretty clearly snarXiv talking.

The toughest questions, including the ones I got wrong, were when snarXiv went for something subtle. For short enough titles, the telltale signs of snarXiv were suppressed. There just weren’t enough buzzwords for a mistake to show up. I’m not sure there’s a way to distinguish titles like that, even for people in the relevant sub-field.

How well do you do at arXiv vs snarXiv? Any tips?