Wednesday, April 18, 2018

Forum with Congressman and Physicist Bill Foster

This is the talk given by Congressman and the only Physicist left in the US Congress, Bill Foster, at this year's APS March meeting.



I have been in attendance to one of Bill Foster's talk before, at the 2011 TIPP conference in Chicago. You may read my "live" reporting of that talk back then, and also a follow-up post on it.

Zz.

Tuesday, April 17, 2018

The Friedmann Equation

Astrophysicist Ethan Siegal picked the Friedmann equation as the "most important" equation in the universe.

The first Friedmann equation describes how, based on what is in the universe, its expansion rate will change over time. If you want to know where the Universe came from and where it's headed, all you need to measure is how it is expanding today and what is in it. This equation allows you to predict the rest!

I don't have the "most important equation" in the universe for my pick, mainly because I don't know the criteria for picking such a thing. And often times, people confuses "interesting" with "important", which need not be mutually inclusive.

It's still fun to read what other physicists think is the most important equation, even if I don't necessarily agree with their picks.

Zz.

Friday, April 13, 2018

An Overview of CLIC at CERN

This is the lesser known effort at CERN among the general public, and yet, it may have one of the most significant impacts coming out of this high-energy physics lab.

CLIC, or the Compact Linear Collider research project at CERN has been studying accelerator science for many years. This is one of a few prominent research centers on accelerator physics throughout the world. Both they and many other accelerator research centers are making advancements in accelerator science that have a direct benefit and application to the general public.

So my intention in highlighting this article is not simply for you to learn what the people at CLIC do. Some of the description may even be beyond your understanding. What you should focus on is all the applications that are already in use, or can be possible in the near future, on the advancements made in this area of physics/engineering. These applications are not just within physics/engineering.

Unfortunately, as I've stated a few times in this blog, funding for accelerator science is often tied to funding in high energy physics, and for the US, the funding profile in this sector has been abysmal. So while accelerator science is actually independent of HEP, its funding has gone downhill with HEP funding over the last few years, especially after the shutdown of the Tevatron at Fermilab.

Whether you support funding, or increase in funding, of this area of study is a different matter, but you should at least be aware and have the knowledge of what you are supporting or not supporting, and not simply make a decision based on ignorance of what it is and what it's implication can be.

Zz.

Tuesday, April 10, 2018

What Astronomers Wish You Know About Dark Matter And Dark Energy

If you do a search of this blog, you will encounter numerous entries on both "dark matter" and "dark energy". It is something I've covered quite often, mainly because it is still an ongoing and active research area in astrophysics/astronomy/cosmology. Even high-energy physics/elementary particle physics is getting into the picture with particle astronomy.

In this article, Ethan Siegel gives you a condensed version of what "dark matter" and "dark energy" are, and what you need to know about them. But more importantly, if you think that you can discard them, you need to do more than just say that they are not needed.

It wasn't always apparent that this would be the solution, but this one solution works for literally all the observations. When someone puts forth the hypothesis that "dark matter and/or dark energy doesn't exist," the onus is on them to answer the implicit question, "okay, then what replaces General Relativity as your theory of gravity to explain the entire Universe?" As gravitational wave astronomy has further confirmed Einstein's greatest theory even more spectacularly, even many of the fringe alternatives to General Relativity have fallen away. The way it stands now, there are no theories that exist that successfully do away with dark matter and dark energy and still explain everything that we see. Until there are, there are no real alternatives to the modern picture that deserve to be taken seriously

It might not feel right to you, in your gut, that 95% of the Universe would be dark. It might not seem like it's a reasonable possibility when all you'd need to do, in principle, is to replace your underlying laws with new ones. But until those laws are found, and it hasn't even been shown that they could mathematically exist, you absolutely have to go with the description of the Universe that all the evidence points to. Anything else is simply an unscientific conclusion.

Zz.

Monday, April 09, 2018

Another "Unconventional" Superconductor?

This is definitely exciting news, because if verified, this will truly open up a whole new phase space for superconductivity.

An advanced publication has appeared reporting the discovery of high-spin state quasiparticles that are involved in superconducitivty.[1] This occurs in a topological semimetal YPtBi.

Previously, superconductivity occurs due to quasiparticles of spin 1/2 forming pairs called Cooper pairs. Now these Cooper pairs can have a total spin of either 0 (singlet state), or 1 (triplet state). This new superconductor seems to be formed by quasiparticles having spin 3/2! The resulting Cooper pairs may have total spin of 3 or 2.

It turns out that based on their measurements, the pairing symmetry appears to be predominantly in the spin state of 3, with a sub-dominant component having 0 (the singlet) state.

If you want to know how a quasiparticle here could have a spin 3/2 state, then you need to learn about spin-orbit coupling that we all learned in intro QM classes, and read the article.

This is utterly fascinating. Just when you think you can't be surprised anymore by the phenomenon of superconductivity, along comes one!

Zz.

[1] H. Kim et al., Sci. Adv.2018;4

Wednesday, April 04, 2018

Twin Paradox - The "Real" Explanation, But With No Math

Don Lincoln made a video a while back explaining the apparent twin paradox, explaining that it isn't due to acceleration. It seems that his audience wanted an explanation, but without using math. He has graciously agreed and this video is his attempt at providing the same explanation, but without all that math in the earlier video.



Is this clearer for people who didn't quite get the first video?

Zz.

Tuesday, April 03, 2018

MinutePhysics Special Relativity Chapter 3

If you missed Chapter 2 of this series, you can check it out here.

Here is Chapter 3, and this is where he uses that thing-ma-jiggy to illustrate Lorentz transformation.



Zz.

Sunday, April 01, 2018

Do A Search On "Physics" and "Physicist"

.. which, btw, is almost the title of this physics blog! :)

Chad Orzel must have been bored when he decided to do a search on the words "physics" and then "physicist". Hilarity ensues.

I'm not surprised that some of these search engines confuse "physicist" and "physician", since many people think people who work in physics are "physician". But a few of those stock photos that he found from Shutterstock are just hilarious. Of course, stereotype abounds, but some of these are so far out in left field, they are hardly relevant.

I guess, subconsciously, this was partly the reason why I did that superficial poll on the most attractive male and female physicist a while back. We all don't look like Albert Einstein, even for our women physicists!

Zz.