Charles Townes

As reported almost everywhere, we lost Nobel Laureate Charles Townes at the age of 99. Oh how we we all are standing on the shoulder of this giant in physics.

Zz.

GUTs and TOEs

Another informative video, for the general public, from Don Lincoln and Fermilab.



Of course, if you had read my take on the so-called "Theory of Everything", you would know my stand on this when we consider emergent phenomena.

Zz.

Macrorealism Violated By Cs Atoms

It is another example where the more they test QM, the more convincing it becomes.

This latest experiment is to test whether superposition truly exist via a very stringent test and applying the Leggett-Garg criteria.

In comparison with these earlier experiments, the atoms studied in the experiments by Robens et al.’s are the largest quantum objects with which the Leggett-Garg inequality has been tested using what is called a null measurement—a “noninvasive” measurement that allows the inequality to be confirmed in the most convincing way possible. In the researchers’ experiment, a cesium atom moves in one of two standing optical waves that have opposite electric-field polarizations, and the atom’s position is measured at various times. The two standing waves can be pictured as a tiny pair of overlapping one-dimensional egg-carton strips—one red, one blue (Fig. 1). The experiment consists of measuring correlation between the atom’s position at different times. Robens et al. first put the atom into a superposition of two internal hyperfine spin states; this corresponds to being in both cartons simultaneously. Next, the team slid the two optical waves past each other, which causes the atom to smear out over a distance of up to about 2 micrometers in a motion known as a quantum walk. Finally, the authors optically excited the atom, causing it to fluoresce and reveal its location at a single site. Knowing where the atom began allows them to calculate, on average, whether the atom moved left or right from its starting position. By repeating this experiment, they can obtain correlations between the atom’s position at different times, which are the inputs into the Leggett-Garg inequality.

You may read the result they got in the report. Also note that you also get free access to the actual paper.

But don't miss the importance of this work, as stated in this review.

Almost a century after the quantum revolution in science, it’s perhaps surprising that physicists are still trying to prove the existence of superpositions. The real motivation lies in the future of theoretical physics. Fledgling theories of macrorealism may well form the basis of the next generation “upgrade” to quantum theory by setting the scale of the quantum-classical boundary. Thanks to the results of this experiment, we can be sure that the boundary cannot lie below the scale at which the cesium atom has been shown to behave like a wave. How high is this scale? A theoretical measure of macroscopicity [8] (see 18 April 2013 Synopsis) gives the cesium atom a modest ranking of 6.8, above the only other object tested with null measurements [5], but far below where most suspect the boundary lies. (Schrödinger’s cat is a 57.) In fact, matter-wave interferometry experiments have already shown interference fringes with Buckminsterfullerene molecules [9], boasting a rating as high as 12. In my opinion, however, we can be surer of the demonstration of the quantumness of the cesium atom because of the authors’ exclusion of macrorealism via null result measurements. The next step is to try these experiments with atoms of larger mass, superposed over longer time scales and separated by greater distances. This will push the envelope of macroscopicity further and reveal yet more about the nature of the relationship between the quantum and the macroworld.

Zz.

I Win The Nobel Prize And All I Got Was A Parking Space

I'm sure it is a slight exaggeration, but it is still amusing to read Shuji Nakamura's response on the benefits he got from UCSB after winning the physics Nobel Prize. On the benefits of winning a Nobel Prize:

 "I don't have to teach anymore and I get a parking space. That's all I got from the University of California." 

 Zz.

Superstrings For Dummies

Here's another educational video by Don Lincoln out of Fermilab. This time, it is on the basic idea (and the emphasis here is on BASIC) of String/Superstrings.



Zz.

Arrow Of Time Due To Gravity?

I just got back from vacation and an unexpected trip out of the country, so I'm still catching up. But when I came across a news article on physics in Business Insider, I had to read it, and you should to. It is on another model to explain the nature of the arrow of time in our universe.

Tentative new work from Julian Barbour of the University of Oxford, Tim Koslowski of the University of New Brunswick and Flavio Mercati of the Perimeter Institute for Theoretical Physics suggests that perhaps the arrow of time doesn’t really require a fine-tuned, low-entropy initial state at all but is instead the inevitable product of the fundamental laws of physics. Barbour and his colleagues argue that it is gravity, rather than thermodynamics, that draws the bowstring to let time’s arrow fly. Their findings were published in October in Physical Review Letters.

The team’s conclusions come from studying an exceedingly simple proxy for our universe, a computer simulation of 1,000 pointlike particles interacting under the influence of Newtonian gravity. They investigated the dynamic behavior of the system using a measure of its "complexity," which corresponds to the ratio of the distance between the system’s closest pair of particles and the distance between the most widely separated particle pair. The system’s complexity is at its lowest when all the particles come together in a densely packed cloud, a state of minimum size and maximum uniformity roughly analogous to the big bang. The team’s analysis showed that essentially every configuration of particles, regardless of their number and scale, would evolve into this low-complexity state. Thus, the sheer force of gravity sets the stage for the system’s expansion and the origin of time’s arrow, all without any delicate fine-tuning to first establish a low-entropy initial condition.

Zz.

Neil Degrasse Tyson's Christmas Tweets Caused A Brouhaha

It seems that a few harmless tweets by Astrophysicist Neil Degrasse Tyson are causing quite a stir on the internet.

Honest, I don't see this as being a big deal. I don't even find it mildly offensive and I wish those people who are criticizing him for it would explain what exactly it is that they don't like. After all, it appears that his words actually meant something for them to either follow him, or take the time to respond. Otherwise, why bother or give a hoot about what he has to say?

There are more offensive things being said and done against Christianity, especially at this time of the year. Picking a fight based on a bunch of FACTS (yes, look closely, he is simply stating FACTS) being presented in a rather cheeky way is a freaking waste of time! So get a GRIP, people!

Zz.

Astronomically Correct Twinkle Twinkle

This is just way too much fun.



Happy Holidays!!

Zz.

Happy Winter Solstice

I'm posting this on Dec. 21, 2014, which is often considered as the Winter Solstice, the shortest day of the year for Northern Hemisphere.

Now most people will associate that with the idea that from this day onwards, sunrise will be earlier and sunset will be later in the day. However, this article shows that that is not the case as they showed in the table.

Day	Sunrise	Sunset	Day length
(All times GMT) Turns out, it has to do with a day not being exactly of the same length all year long. There are two reasons why the length of the solar day varies, the first being the fact that the axis of the Earth's rotation is tilted - 23.5 degrees from vertical - and second, the Earth's speed varies because it moves in an elliptical orbit around the sun, accelerating when it is closer to the star's gravitational pull and decelerating when it is further away. The sun therefore in effect lags behind the clock for part of the year, then speeds ahead of it for another. So there you go! Zz.
11 December 2014	07:56	15:51	7:55:37
21 December 2014	08:04	15:53	7:49:45
31 December 2014	08:06	16:01	7:54:39
31 January 2015	07:41	16:48	9:06:42

Defending The Integrety Of Physics

The suggestion made by a few theorists that theoretical physics, at least some aspect of it, should be accepted merely based on "aesthetics" and not from experimental verification is downright STUPID! This is highlighted in the opinion piece published in Nature recently (I don't know how long this article is available online for free, so read it now!).

This year, debates in physics circles took a worrying turn. Faced with difficulties in applying fundamental theories to the observed Universe, some researchers called for a change in how theoretical physics is done. They began to argue — explicitly — that if a theory is sufficiently elegant and explanatory, it need not be tested experimentally, breaking with centuries of philosophical tradition of defining scientific knowledge as empirical. We disagree. As the philosopher of science Karl Popper argued: a theory must be falsifiable to be scientific.

Without experimental verification, then such ideas are no longer physics but rather, a religion. You accept things purely on a matter of faith, or beauty, or elegance, etc.. without being able to empirically show that it is valid.

I will fight tooth and nail to make sure physics doesn't go into that rout. If these theorists want to pursue such a thing, then they should stop calling themselves physicists and start their own religion.

Zz.

2014 Physics Gift Guide

Rhett Allain has some suggestions for gift-giving during this holiday season. Why he called his post a "physics gift guide", most, if not all, of the items are more "technical" and engineering in nature (except for books, of course).

I would add to that list something that a physicist or physics student might find useful. How about a scientific spreadsheet and plotting software? Many of these, such as Origin, are horribly expensive to own individually. But something such as Psi-Plot is quite affordable and has almost all the bells and whistles that one would need.

For a casual physics enthusiast, especially those who are caught up in al the hoopla with particle physics and the Higgs, one could get merchandise with various "geeky" prints at zazzle.

Do you have anything to add to this list?

Zz.

LEGO Particle Accelerator

Hey, if you have time to burn, why not build your own LEGO particle accelerator?



Here's the synopsis accompanying the YouTube video:

This is a working particle accelerator built using LEGO bricks. I call it the LBC (Large Brick Collider). It can accelerate a LEGO soccer ball to just over 12.5 kilometers per hour. Watch the follow up video to see how it works: http://youtu.be/sjRPTDgjM0Q If you would like to see this potentially become an official LEGO set be sure to head over to LEGO Ideas and support the project! https://ideas.lego.com/projects/86253 You can find more information about how it works on my website at http://jkbrickworks.com/lego-particle...

Zz.

Fermilab Physics Slam 2014

A very entertaining video to watch if you were not at this year's Physics Slam.



Zz.

Research Gate

Anyone else here on Research Gate?

First of all, let me first declare that I'm not on Facebook, don't have a Twitter account, etc.. etc. This blog is my only form of "social media" involvement in physics, if you discount online physics forums. So I'm not that into these social media activities. Still, I've been on Research Gate for several years after being invited into it by a colleague.

If you're not familiar with it, Research Gate is a social media platform for ... you guessed it ... researchers. You reveal as much about yourself as you wish in your profile, and you can list all your papers and upload them. The software also "trolls" the journals and online to find publications that you may have authored and periodically asks you to verify that they are yours. Most of mine that are currently listed were found by the software, so it is pretty good.

Of course, the other aspect of such a social media is that you can "follow" others. The software, like any good social media AI, will suggest people that you might know, such as your coauthors, people from the same institution as yours, or any other situation where your name and that person's name appear in the same situation or document. It also keeps tabs on what the people that follows you or ones that you follow are doing, such as new publications being updated, job change, etc.. etc. It also tells you how many people viewed your profile, how many read your publications, and how many times your publications have been downloaded from the Research Gate site.

Another part of Research Gate is that you can submit a question in a particular field, and if that is a field that you've designated as your area of expertise, it will alert you to it so that you have the option of responding. I think this is the most useful feature of this community because this is what makes it "science specific", rather than just any generic social media program.

I am still unsure of the overall usefulness and value of this thing. So far it has been "nice", but I have yet to see it as being a necessity. Although, I must say, I'm pleasantly surprised to see some prominent names in my field of study who are also on it, which is why I continued to be on it as well.

So, if you are also on it, what do you think of it? Do you think this will eventually evolve into something that almost all researchers will someday need?

Zz.

"Should I Go Into Physics Or Engineering?"

I get asked that question a lot, and I also see similar question on Physics Forums. Kids who are either still in high school, or starting their undergraduate  years are asking which area of study should they pursue. In fact, I've seen cases where students ask whether they should do "theoretical physics" or "engineering", as if there is nothing in between those two extremes!

My response has always been consistent. I why them why can't they have their cake and eat it too?

This question often arises out of ignorance of what physics really encompasses. Many people, especially high school students, still think of physics as being this esoteric subject matter, dealing with elementary particles, cosmology, wave-particle duality, etc.. etc., things that they don't see involving everyday stuff. On the other hand, engineering involves things that they use and deal with everyday, where the product are often found around them. So obviously, with such an impression, those two areas of study are very different and very separate.

I try to tackle such a question by correcting their misleading understanding of what physics is and what a lot of physicists do. I tell them that physics isn't just the LHC or the Big Bang. It is also your iPhone, your medical x-ray, your MRI, your hard drive, your silicon chips, etc. In fact, the largest percentage of practicing physicists are in the field of condensed matter physics/material science, an area of physics that study the basic properties of materials, the same ones that are used in modern electronics. I point to them many of the Nobel Prize in physics that were awarded to condensed matter physicists or for invention of practical items (graphene, lasers, etc.). So already, the idea of having to choose between doing physics, and doing something "practical and useful" may not be mutually exclusive.

Secondly, I point to different areas of physics in which physics and engineering smoothly intermingle. I've mentioned earlier about the field of accelerator physics, in which you see both physics and engineering come into play. In fact, in this field, you have both physicists and electrical engineers, and they often do the same thing. The same can be said about those in instrumentation/device physics. In fact, I have also seen many high energy physics graduate students who work on detectors for particle colliders who looked more like electronics engineers than physicists! So for those working in this field, the line between doing physics and doing engineering is sufficiently blurred. You can do exactly what you want, leaning as heavily towards the physics side or engineering side as much as you want, or straddle exactly in the middle. And you can approach these fields either from a physics major or an electrical engineering major. The point here is that there are areas of study in which you can do BOTH physics and engineering!

Finally, the reason why you don't have to choose to major in either physics or engineering is because there are many schools that offer a major in BOTH! My alma mater, the University of Wisconsin-Madison (Go Badgers!) has a major called AMEP - Applied Mathematics, Engineering, and Physics - where with your advisor, you can tailor a major that straddles two of more of the areas in math, physics, and engineering. There are other schools that offer majors in Engineering Physics or something similar. In other words, you don't have to choose between physics or engineering. You can just do BOTH!

Zz.

The Physics of Thor's Hammer

Not that you should take any of these seriously, but some time, entertainment reading like this can be "fun".

Jim Kakalios, the author of The Physics of Superheroes, has written an article on the physics of Thor's hammer. I think what I am more interested in is the details trying to explain the initial inconsistencies of what was seen (such as the hammer appearing to be too heavy for everyone to lift, yet, it isn't so heavy that it crushed the books and table that it was resting on). I think that is more fascinating because in many storyline, such inconsistencies are often either overlooked or simply brushed aside. To me, that is where the physics is, because someone who notices such inconsistencies are very aware of the physics, i.e. if such-and-such is true, then how come so-and-so doesn't also occur?

Zz.

Newton Lecture 2014

The 2014 Newton Lecture given by Deborah Jin, who to me, already deserves a Nobel Prize in physics.



Zz.

"I Just Don't Understand Physics"

Rhett Allain has a very good article that is full of advice and suggestion for students having problems with their physics classes.

This is what he has to say when students tell him they just don't understand physics.

This is something I often hear students say around the midterm. The truth is that no one “just understands” physics. No. Instead, physics is the result of a battle. There is battle in your head between common ideas and new ideas. There is a struggle in your mind and on your paper about finding a strategy to solve a problem.

You can’t just “get physics” by going to class. Understanding in physics only comes (for just about all of us) through sweat and tears. You have to do the homework. You have to go to class. You have to read the textbook. This isn’t drive-thru learning. If you aren’t putting in the time, you are going to make progress.

This is similar to what I've said all along on here, that you just can't sit and read a book on physics and hope to understand it. What you may have understood is something superficial. The only way to grasp the knowledge is by solving a bunch of problems, making mistakes, and learning from them. That is the only way to get a feel of the essence of what you are learning. I've always used the analogy of learning how to ride a bicycle. You can read and hear people tell you how to ride a bike till you're blue, but you'll never acquire the skill to ride it till you actually sit on a bike and practice, practice, practice. You will fall a few times, get a few scrapes and bruises, before you finally get it.

The same thing with understanding physics.

Zz.

Bay Area

Greetings from Berkeley, CA.

This is the view from the Adanced Light Source at Lawrence Berkeley National Lab. It overlooks the main campus of UC-Berkeley, downtown Berkeley, the bay, and foggy San Francisco in the far background.

Building Blocks Of Matter

A lecture that should be accessible at the general public level.



Zz.