Saturday, November 28, 2015

What Good Is Particle Physics?

I've tackled this issue a few times on here, such as in this blog post. In this video, Don Lincoln decides to address this issue.


Wednesday, November 25, 2015

Hot Cocoa Physics

Just in time for the cold weather, at least here in the upper northern hemisphere, APS Physics Central has a nice little experiment that you can do at home with your friends and family. Using just a regular mug, hot water/milk, cocoa mix, and a spoon, you can do a demo that might elicit a few questions and answers.

For those celebrating Thanksgiving this week, I wish you all a happy and safe celebration.


Monday, November 16, 2015

Symmetry And Higgs Physics Via Economic Analogy?

Juan Maldacena is trying to do the impossible: explain the symmetry principles and the Higgs mechanism using analogies that one would find in economics.

I'm not making this up! :)

If you follow the link above, you will get the actual paper, which is an Open Access article. Read for yourself! :)

I am not sure if non-physicists will be able to understand it. If you are a non-physicist, and you went through the entire paper, let me know! I'm curious.


Wednesday, November 11, 2015

What Is Computational Physics?

Rhett Allain has published his take on what "computational physics" is.

Many of us practicing physicists do work in computational physics. Some very often, some now and then. At some point, many of us have to either analyze data, do numerical modeling, or solve intractable equations. We either use pre-made codes, modify some other computer codes, write our own code, or use commercial software.

But certainly, this is less involved than someone who specializes in computational physics. But many of us do have the need to know how to do some of these things as part of our job. People who have to simulate particle beam dynamics, and those design accelerating structures are often accelerator physicists rather than computational physicists.

Hum... now I seem to be rambling on and can't remember the point I was trying to make. Ugh! Old age sucks!


Monday, November 09, 2015

100 Years Of General Relativity

General Relativity turns 100 years this month. The Universe was never the same again after that! :)

APS Physics has a collection of articles related to various papers published in their family of journals related to GR. Check them out. Many are fairly understandable to non-experts.


Thursday, November 05, 2015

The Physics Of Sports That "Defy Physics"

I love this article, and it is about time someone writes something like this.

Chad Orzel has a nice article explaining why the often-claimed event in sports that "defy physics" actually happened BECAUSE of physics.

Of course, as several physicists grumbled on Twitter this morning, “defied physics” is a silly way to describe these plays. These aren’t happening in defiance of physics, they’re happening because of physics. Physics is absolute and universal, and never defied– the challenge and the fun of these plays is to explain why and how these seemingly impossible shots are consistent with known physics.

What is being "defied" is one's understanding and expectations of what would happen and what looked seemingly impossible to happen. This is DIFFERENT than discovering  something that "defies physics", and that is what many people, especially sports writers and TV heads do not seem to understand. The fact that these people often lack any deep understanding of basic physics, but somehow seem to clearly know when something they don't understand well is being "defied", appears to be lost in all of this. It is like me, having never visited France or know much about the French people, making a claim that something isn't consistent with that country or people simply based on what I understand from watching TV.

I wish they stop using the phrase "defy physics" in situation like this the same way I wish reporters stop using the phrase "rate of speed" when they actually just mean "speed"!


Kamioka, Japan

With the recent Nobel Prizes in physics going to various discovery related to neutrinos, this Nature article is highly appropriate. We usually do not get a glimpse of the site where many of these experiments are performed. So it is nice to have a bit of a background on Kamioka, Japan, and also the various neutrino detectors and experiments that had gone on there. Considering that this is the place where Kamiokande, Super-Kamiokande, and the KamLAND experiments were done, this is a major site for neutrino-based studies.


Wednesday, November 04, 2015

The Particle Physics Of You

You are made up of a lot, and I mean, A LOT, of elementary particles. This Symmetry article reveals a bit more of what particles formed you, and their basic properties and history.

But what I'm sure many of you do not realize is that you are also the source of radioactivity.

Your body is a small-scale mine of radioactive particles. You receive an annual 40-millirem dose from the natural radioactivity originating inside of you. That’s the same amount of radiation you’d be exposed to from having four chest X-rays. Your radiation dose level can go up by one or two millirem for every eight hours you spend sleeping next to your similarly radioactive loved one. 

So next time you run into someone who is rabid anti-radiation and claims that no amount of radiation is safe, tell him/her to ban him/herself.


Saturday, October 31, 2015

Leo Kadanoff

This past week marked the passing of a giant in the field of physics - Leo Kadanoff. The public won't know  him, but those of us in physics, especially in Condensed Matter and Statistical Physics, will have heard of him and his numerous contributions to these field of studies.

“Leo was a prodigious scientist,” said his longtime UChicago colleague Sidney Nagel, the Stein-Freiler Distinguished Service Professor in Physics. “His work on statistical mechanics is one of the great achievements of 20th-century theoretical physics. It laid the conceptual and mathematical foundations for some of the most insightful and effective tools on which our modern understanding of nature is based.”

Kadanoff’s work has applications throughout physics, ranging from condensed matter (liquids and solids) to elementary particles, Nagel said, with the reach of his work extending to mathematics and other sciences.

I mentioned about the review paper that he wrote phase transition and the mean-field theorem quite a while back. And of course, those of you who had subscribed to Physics Today for a long time would have read his rather critical review of Stephen Wolfram's book "A New Kind of Science", in which in the end he said "... I cannot support the view that any “new kind of science” is displayed in NKS. I see neither new kinds of calculations, nor new analytic theory, nor comparison with experiment...." That rather sealed the deal for me.

He will be sorely missed.


Tuesday, October 27, 2015

"I Want To Do High Energy Physics"

So you are a physicist in the US, and you're having a casual conversation with a bunch of new physics graduate students. When you ask them what they intend to major in (a very obvious question to ask in a situation like this), some of them say "I want to major in high energy physics".

What do you say in return? Do you just say "Well, good luck!" and leave it at that? Or do you feel a sense of responsibility to tell these students of the prospect that they will face here in the US for someone with that major?

This issue is nothing like the issue with students wanting to do "theoretical physics", because these students, presumably, a smart enough to know the area that they are going into. However, while they have a good idea of the nature of the subject matter, they have very little idea of the funding, job prospects, etc. of those people who graduated with that degree. And for HEP, the outlook is even bleaker than a lot of the other areas in physics for someone who wants to have a career in that field. The US funding for HEP has consistently been cut year after year, and especially more so after the Tevatron at Fermilab shut down. While many in the US collaborate on work done at the LHC, funding for the HEP division of DOE's Office of Science continues to shrink, and it doesn't look any better in the future.

So, knowing all this, what would you say to such students? Do you try to persuade them to change their minds and tell them that it is not to late to switch to a different field of physics? Do you lay out the reality of the situation? Do you tell them that if they still wish to continue, they need to be prepared for the possibility that they will not be able to pursue a career in such a field?

In my case, walking away and not say anything is not an option. I somehow feel some level of "paternal" responsibility towards these kids, and I can't just let them go into something blindly without at least giving them some dose of reality. Whether they listen to it or not is an entirely different matter, but at least I tried.


Thursday, October 22, 2015

Local Realism - Is It Dead Yet?

There have been several tests that have been conducted that pointed to the violation of local realism and consistent with quantum mechanics. I've indicated at least two recently (this, and this). Now come the most spectacular demonstration yet of such violation, and this one comes from what the authors claim to be an experiment free of the detection loophole and locality loophole.

The preprint appeared a while back on ArXiv, but the paper has finally been published in this week's issue of Nature (Oct. 21, 2015). So even if you don't have access to the Nature article, you should be able to read the preprint.


Wednesday, October 21, 2015

What Is A Multiverse?

Good question. This video might address that:

I must say that the majority of instances that I come across a discussion of Multiverse is online, in a forum where non-physicists are more apt to be impressed by it and to even consider it seriously. Maybe I don't hang around too many physicists who are working in this area, but the overwhelming majority of physicists that I encounter couldn't be bothered by this topic.

Now, it is not that they, and I, are dismissing it. Like Don Lincoln in the video, I think I'll pay more attention to it, and put time and effort to try and appreciate it ONLY when there are strong indications that such an idea might be right. This means that there are signs of observational/experimental agreement that distinguish  it from other theories. Until that happens, Multiverse is nothing more than one of the numerous ideas out there that cannot be tested and have no experimental verification.

That isn't harsh, is it?