Solve QM Particle-In-A-Box Problem Using Code

Rhett Allain shows you how to solve the standard 1D infinite square well problem using numerical method.

I know he is using this as a simple illustration, but it is more useful, especially to physics students, if he solves this for a finite square well.

But still, for the general public, this might be complicated enough. I wonder if someone with just computer coding but little physics can code this successfully. If you fall under this category, let me know how you did if you took up this task.

Zz.

Simple Physics?

I'm all for explaining things in simple terms that the general public can understand. I do that frequently, especially when I'm doing an outreach project or hosting visitors to the facility.

So when I read a review of this book, Thing Explainer: Complicated Stuff In Simple Words by Randall Munroe, it sounds like something that can be recommended to a lot of people who are curious about how various things around them work.

However, this author, and the reviewer of this book, fall into the same cliche trap that is one of my pet peeve.

There’s a nice quote attributed to the physicist Ernest Rutherford (or is it Einstein?): “If you can’t explain your physics to a barmaid, it is probably not very good physics.” There are variations of the theme, such as, “You do not really understand something unless you can explain it to your grandmother”. In essence, keep it as simple as possible.

I had already addressed the fallacy of this statement (and yes, I am challenging Rutherford or Einstein if they actually said such a silly thing). I have plenty of evidence to point to the contrary. I wish people who keep repeating this would actually read my counter point, but hey, what are the odds?

Zz.

Professional Climate for LGBT Physicists

Many different issues have been discussed regarding challenges faced by women and minorities in physics. Unfortunately, very little effort has been dedicated to the challenges faced by gay, lesbian, bisexual, and transgender physicists. And yes, there ARE LGBT physicists, even if you are not aware of their existence.

The APS, to their credit, has taken steps to address this. This study is the first such report to discover the state of the profession and how LGBT physicists fare in the current climate.

In the general membership survey demographic question (sent to a random sample of society members), just 2.5 percent of total respondents identified as LGBT over all, and 14 percent preferred not to provide such information. But U.S. respondents were twice as likely (3 percent) to answer as non-U.S. respondents. Respondents between 18 and 25 years of age were significantly more likely than the overall population to identify as LGBT, at 16 percent, suggesting a generational shift in comfort disclosing their status (just 6 percent of respondents in that age group declined to provide an answer).

Committee members found that LGBT physicists face uneven protection and support for legislation and policies, both in the U.S. and abroad. Some 50 percent of survey respondents rated their campus or workplace policies as “highly supportive” or “supportive,” while 30 percent characterized them as “uneven,” “lacking” or “discriminatory.” Only 40 percent of transgender respondents said their workplaces were supportive to some degree.

I personally have not observed any hostility towards LGBT physicists or even LGBT personnel in my professional career. Of course, the environment where I worked (US National Labs and Universities) already have policies strictly prohibiting discrimination and harassment against such group. I am sure others in various situations, such as private industries, will have a different atmosphere to deal with, So this study is definitely needed to have a snapshot of the situation at this point in time.

Zz.

In Praise Of APS March Meeting

The APS March Meeting is the LARGEST yearly gathering of physicists in the world. Yet, as Chad Orzel has stated, it is hardly covered by the media.

In this article, Orzel writes why this is so, and why the media and the public should pay more attention to this gathering.

As with lots of things, though, the primary reason for the difference is probably money. Which, in a way, goes back to the irony noted above. Particle physics as a discipline puts a lot more effort into popularization because they have to in order to get funding. Fundamental physics experiments produce some spin-off benefits, but those are second-order effects, difficult to predict and harder to monetize.

Condensed matter research, on the other hand, leads to a more direct payoff, and thus comes with a more secure funding stream. You don’t have to work all that hard to convince wealthy industrialists that it’s worthwhile to spend money on developing new materials that will lead to new and improved commercial products. The funding stream for the field is a little more secure, thanks to the more direct path to applications, and thus there’s less need to make the effort to explain a complicated subject. Which then feeds back into the first two reasons.

This is kind of a shame, because when you dig into it, a lot of what goes on in condensed matter is just as amazing as what you see in particle physics. In fact, a lot of effort goes into creating analogues of exotic systems. And if you look at it the right way, there’s some quantum magic in the most basic aspects of the ways solid objects come together.

Certainly, the sexiness of the topic makes a big difference. But as I've stated many times on here, physics isn't just the LHC and the Big Bang. It is also your iPhone and your MRI. And it is about time the public is more aware of this.

Zz.

"That Physics Show" Opens Off-Broadway

I mentioned this a while back. It is certainly an ambitious and daring move, to do a stage presentation of nothing but a series of physics demonstration. Would this get an audience, much less, a paying audience?

In any case, "That Physics Show" has opened off-Broadway in NY City.

That Physics Show officially opens March 9 for an open-ended run at the Elektra Theater Off-Broadway. The show, which began previews February 26, features "scientific magic" by physics demonstrator David Maiullo.

A regular on The Weather Channel, Maiullo brings more than 20 years of experience teaching physics at Rutgers University. The show is directed and produced by Eric Krebs. 

However, an early review of it hasn't been too enthusiastic.

Maiullo is not a natural performer, but once he starts igniting hydrogen balloons, smashing beer cans with ping pong balls, dunking fresh flowers into a deep freeze, and using a bowling ball as a pendulum, you don’t mind.

But that’s the extent of the “show” in “That Physics Show.” Maiullo pretends that his his geeky explosions and frenetic motion are meant to demonstrate several of the laws of physics, but he moves between the displays so quickly that he doesn’t end up connecting any dots.

We will have to see how successful this is. I'm more interested in finding out if people actually LEARNED anything from seeing this show. It is hard to produce an entertainment but also trying to teach people something new.

Zz.

Did Physicists Failed To Explain Clearly To The Public About The LIGO Discovery?

OK, this came out of left-field, because I didn't read the Nature Physics editorial.

This is a Physics Today comment on an editorial that appeared in Nature Physics regarding the recent LIGO discovery of gravitational wave. In it, the Nature Physics editors seem to indicate that physicists have failed to clearly convey to the public what gravitational wave is and how the discovery was made.

In “a triumph of ingenuity and perseverance,” exulted the thumbnail summary atop a 1 March Nature Physics editorial, physicists “have finally detected gravitational waves.” The summary continued: “And now we need to explain them to the general public.” The editors charged that the public’s response was largely summed up in this Daily Mash satire headline: “Scientists completely fail to explain ‘gravitational waves.’” The editorial declared that physicists “should learn to explain the physics of these spectacular events to non-physicists.”

But that is where things get rather interesting and puzzling at the same time. You see, as the Physics Today comment indicated, there has been NO evidence that physicists have failed to clearly convey this discovery to the public. What Nature Physics editors have used as their "evidence", which is from the Daily Mash, is actually a satirical piece, very much like The Onion here in the US. The Physics Today comment brought up its own evidence on how this discovery has been covered and explained many different times and many different ways by a number of prominent physicists appearing in several media forms.

So, not only did Nature Physics editorial not able cite a single, valid evidence to back their claim, but there are clearly evidence to the contrary! For a "science" journal, this is a serious lapse, because the very basic method of having evidence to support one's claim is fundamental to having a valid idea or conclusion.

I'd like to hear Nature Physics response to this charge.

Zz.

Socio-Economic Impact of the LHC

This is an interesting analysis of the impact of the LHC, especially in terms of economics.

I think many politicians and the general public do not realize that even for something that is built to study something that appears to be esoteric and no direct and immediate application, there can be immediate benefits socially and economically.

That is why I continue to be surprised and appalled that the US continue to not "care" about their loss in having any kind of high-energy physics particle collider on their soil anymore. This is especially puzzling in light of the fact that other parts of the world are seriously pursuing having such experiments within their borders, even if it is under an international collaboration. Certainly China is pursuing having such facilities, and Japan just announced the start of an electron-positron collider. As far as I'm aware of, Japan is the leading contender for hosting the International Linear Collider (ILC), something that Fermilab has also been pursuing.

But with the devastating budget issues in the US, this is looking to be very bleak. People seem to only see the money being spent on such facilities, without realizing the significant impact not only on the intellectual aspect of it, but the economic impacts, both short-term and long-term. An analysis done in this preprint may not make it to the people who hold the power, but it is certainly there to be seen.

Zz.

Physics First

It is interesting that something  like this that has been pushed for for years, can still make the news.

A middle school in New Jersey has revised its curriculum and puts physics first, ahead of biology and chemistry, for students taking science classes.

Egg Harbor City is part of a movement to rethink how science is taught. Instead of taking biology, chemistry, then maybe physics in high school, students will take algebra-based physics first, at the same time they take algebra, then take biology and chemistry.

That's radical, dudes!

Or is it? Anyone who has followed the field of physics education would have remembered way back in the end of the last century and into this one of this effort to put physics first, championed by Nobel Laureate Leon Lederman.

Of course, it is easier said than done. The ability to do this is very much tied to the ability of the teachers that conduct these classes. I believe that there were extensive training programs for these teachers in trying to implement this concept, and I don't know to what extent this is continuing, or even if this concept is even practiced anywhere else.

I've always told my students that out of the three science subjects, which are physics, chemistry, and biology, physics is the one they are most familiar with and should come naturally to them. Of  course, they look at me as if I said something outrageous, because everyone has the impression that physics is the most difficult out of the three sciences. I tell them that they are already familiar with the workings of physics, that the concept of mechanics, thermodynamics, electricity, etc. are something they use everyday and even take for granted.

I tell them that they already have some QUALITATIVE idea of physics. What we do teach in physics classes is a way to describe these familiar phenomena QUANTITATIVELY. This is where we go beyond "What goes up, must come down" and add "where and when it will come down". That is physics. The mathematical description of many of these familiar events is what separate a pedestrian understanding of something and a physics description of it.

But these events and phenomena are familiar things. In chemistry and biology, you have to deal with things that are not often common, everyday encounters. Maybe if you cook everyday, then chemistry is indirectly something you commonly do. But still, you deal also with a lot of thermodynamics and mechanics. Physics is something you deal with every day and almost every second of the day. You are just not aware of it.

So it should be familiar, not foreign. And putting it first is logical, because it is that familiar.

Zz.

A Tale Of A Particle With Two Names

Physics Focus this week has a brief but fascinating history of the J/Psi particle and its discovery that led to it having two different names.

When two separate groups, using different types of accelerators, get practically the same result, it is difficult not to be convinced by something like that. Ah, but back then, way back in the 70's, the US had several high energy physics colliders like this where multiple facilities were producing results.

Now, the US has none, not even one (RHIC and CEBAF are nuclear physics facilities/colliders).

Zz.

If The Laws Of Physics Don't Apply....

"... what would the law of physics say about such-and-such?"

I've heard of many dumb and stupid things online over the many, MANY years I've been on the 'net (since 1989, if you have to ask!), but somehow, this one caught my eyes more than others.

I'm not going to point out where I recently read it, but this issue is not about physics, but rather with how irrational certain things are, and how irrational people can be without realizing it. If you are in the US and being immersed in the General Election fever, I'm sure you'll understand this. But it doesn't lessen the impact and the surprise for me, because many of these things are so obviously ridiculous. But yet, the people who muttered them don't seem to care how foolish they sounded.

BTW, when this person in question was told that since he is discarding the laws of physics in the first place, why not make up any kind of rules that he wants? And guess what? He didn't want to. He still wanted a "rational" explanation on how physics would explain something that doesn't follow the laws of physics.

Precious!

Zz.

LIGO Discovery And The Nobel Prize

Inevitably, the discussion that follows after the LIGO announcement of the detection of gravitational wave is the Nobel Prize. If there is a sure thing with regard to the Nobel Prize, is that this discovery will get someone this prize.

But just like the issue surrounding the discovery of the Higgs, the question comes up on who should deserve the prize for this discovery. Just like the Higgs, thousands of people were responsible in the work, both theorists and experimentalist. And typically, the Nobel committee will give the award to the individuals who either headed the collaboration, or made the most significant contribution to the physics that led to the discovery.

This news article lists the three most likely individuals who might be the front-runner for the Nobel Prize for this LIGO discovery.

"I think that most of the community would agree that the three pioneers of what became LIGO would be Rainer Weiss, Kip Thorne, and Ronald Drever," the head of one of LIGO's observatories in Hanford, Washington, Fred Raab, told Business Insider.

Weiss — who is a professor at MIT's Department of Physics — and Drever — now retired — are both experimentalists who made significant contributions to the concept, design, funding, and eventual construction of LIGO.

On the other hand, Thorne is a theorist, and the Feynman Professor of Theoretical Physics at CalTech. Together with his students, Thorne conducted much of the work on what the detection of a gravitational wave would actually look like and how to identify that signal within the data

Unfortunately, Ronald Drever is in poor health, and the Nobel prize is not awarded posthumously. They may also have missed the deadline for this year's Nobel prize.

The news article discuss on whether the Nobel prize should increase the number of recipient from the maximum of 3 for each prize (outside of the Peace price). I think the change should be more on awarding the prize to deceased individuals. So what if that person is dead? If he/she did make a major enough contribution to warrant a prize, then it should be done. This is especially true for many women scientists who never received their recognition while they were alive back when women were not encouraged or had severe restrictions on their careers as scientists. Posthumous awards can correct these injustices.

Zz.

LIGO Reports Detection of Gravitational Wave

LIGO has officially acknowledged of the detection of gravitational wave.

Now, in a paper published in Physical Review Letters on February 11, the Laser Interferometer Gravitational-Wave Observatory (LIGO) and Virgo collaborations announce the detection of just such a black hole merger — knocking out two scientific firsts at once: the first direct detection of gravitational waves and the first observation of the merger of so-called binary black holes. The detection heralds a new era of astronomy — using gravitational waves to “listen in” on the universe.

In the early morning hours of September 14, 2015 — just a few days after the newly upgraded LIGO began taking data — a strong signal, consistent with merging black holes, appeared simultaneously in LIGO's two observatories, located in Hanford, Washington and Livingston, Louisiana.

Notice that this is the FIRST time I'm even mentioning this here, considering that for the past 2 weeks, at least, the rumors about this have been flying around all over the place.

Looks like if this is confirmed, we know in which area the next Nobel prize will be awarded to.

There is also a sigh of relief, because we have been searching for this darn thing for years, if not decades. It is another aspect of General Relativity that is finally detected.

Zz.

This Educational Video on Accelerators Doesn't Get It

OK, before you send me hate mail and comments, I KNOW that I'm hard on this guy. He was probably trying to make a sincere and honest effort to explain something based on what he knew. And besides, this video is from 2009 and maybe he has understood a lot more since then.

But still, this video is online, and someone pointed this out to me. I get a lot of these kinds of "references" from folks online, especially with Wikipedia entries. And try as I might to ignore most of these things, they ARE out there, and some of these sources do have not only misleading information, but also outright wrong information.

This video, made presumably by a high-school science teacher, tries to explain what a particle accelerator is. Unfortunately, he described what a particle accelerator CAN do (i.e. use it in high energy physics colliders), but completely neglected the description of a "particle accelerator". This is a common error because most people associate particle accelerator with high energy physics, and think that they are one and the same.

They are not!


As I've stated in an earlier post, more than 95% of particle accelerators on earth has NOTHING to do with high energy physics. One of these things might even be in your doctors office, to generate x-rays to look at your insides. So using high energy physics experiment to explain what a particle accelerator is is like using creme brulee to describe what a dessert is. Sure, it can be a dessert, but it is such a small, SMALL part of a dessert.

A particle accelerator  is, to put it bluntly, a device to accelerate particles! Period. Once they are accelerated, the charge particles can then be used for whatever they are needed for.

Now, that may sounds trivial to you, but I can assure you that it isn't. Not only does one need to accelerate the charge particles to a set energy, but in some cases, the "quality" of the accelerated particles must be of a certain standard. Case in point is a quantity called "emittance". If these are electrons, and they are to be used to generate light in a free-electron laser, then the required emittance, especially the transverse emittance, can extremely low (in fact, the lower the better). This is where the study of beam physics is crucial (which is a part of accelerator physics).

The point I'm trying to make here is that the word "particle accelerator" is pretty generic and quite independent of "high energy physics" or "particle collider". Many accelerators don't even collide these particles as part of its operation (in fact, many do NOT want these particles to collide, such as in synchrotron radiation facilities).

What this teacher neglected to describe is HOW a particle accelerator works. The idea that there are these accelerating structures with a wide range of geometries, and they can have either static electric field, or oscillating electric field insides of these structures, that are responsible for accelerating these charged particles, be it electrons, protons, positrons, antiprotons, heavy nucleus, etc... And even for high energy physics experiments, they don't usually collide with a "fixed" target, as implied in the video. Both LEP, the Tevatron, the LHC, etc. all collide with beams moving in the opposite direction. The proposed International Linear Collider is a linear accelerator that will collide positrons and electrons moving toward each other in opposite direction.

So while the intention of this video is noble, unfortunately, the information content is suspect, and it missed its target completely. It does not really explain what a particle accelerator really is, merely what it can be used for. It also perpetuates the fallacy that particle accelerators are only for these exotic experiments, when they are definitely not.

Zz.

The Physics of Mirrors Falls Slightly Short

This is a nice, layman article on the physics behind mirrors.

While they did a nice job in explaining about the metal surface and the smoothness effect, I wish articles like this will also dive in the material science aspect of why light, in this case visible light, is reflected better off a metal surface than none metalllic surface. In other words, let's include some solid state/condensed matter physics in this. That is truly the physics behind the workings of a mirror.

Zz.

Wendelstein 7-X' Comes Online

ITER should look over its shoulder, because Germany's nuclear fusion reactor research facility is coming online. It is considerably smaller, significantly cheaper, but more importantly, it is built and ready to run!

Construction has already begun in southern France on ITER, a huge international research reactor that uses a strong electric current to trap plasma inside a doughnut-shaped device long enough for fusion to take place. The device, known as a tokamak, was conceived by Soviet physicists in the 1950s and is considered fairly easy to build, but extremely difficult to operate.

The team in Greifswald, a port city on Germany's Baltic coast, is focused on a rival technology invented by the American physicist Lyman Spitzer in 1950. Called a stellarator, the device has the same doughnut shape as a tokamak but uses a complicated system of magnetic coils instead of a current to achieve the same result.

Let the games begin!

Zz.

Will You Be Doing This Physics Demo For Your Students?

I like my students, and I love physics demos, but I don't think I'll be doing THIS physics demo anytime soon, thankyouverymuch!



It is a neat effect, and if someone else performed this, the media would have proclaimed this as "defying the laws of physics".

Maybe I can do a demo on this on a smaller scale, perhaps  using a Barbie doll. And if you ask me how in the world I have a Barbie doll in my possession, I'll send my GI Joe to capture you!

Zz.

2 Most Dangerous Numbers? Phooey!

Baloney!

This is a report on a TED talk by a CERN physicist Harry Cliff. In it, he discussed the conundrum theoretical physicists are facing with the current knowledge of the Higgs and dark energy.

At the core of Cliff's argument are what he calls the two most dangerous numbers in the universe. These numbers are responsible for all the matter, structure, and life that we witness across the cosmos.

So in the attempt to make this story more "sexy", we of course have to make sound as if we are reaching an apocalyptic problem that will spell "the end of physics" (how many times have you heard that already?). There are several problems with this reporting:

1. The degree of certainty on the validity of ANY of these theories is LOW. Anyone wants to argue that? So while it is certainly important to pursue it, the TED talk can only be seen as being a very quick and superficial snapshot of an ONGOING and still preliminary investigation! Our knowledge of the Higgs and dark energy are still in the extreme infancy when compared to many of the more established areas. This is like groping in the dark and then pronouncing that we're doom because someone  heard something moving.

2. The claim that "getting answers could be impossible" is false. In that section of the report, nothing that was described is impossible. The limit on the energy of the LHC isn't a limitation on the physics or our ability. We can certainly build a bigger, more energetic collider (the Superconducting Supercollider that was supposed to be built in Texas in the 80's would have had a higher energy than the LHC!). New research on advanced acceleration scheme, led by a slew of wakefield-type accelerators, has the potential of boosting particle energy even higher while making the accelerator more compact. So no, there is no ceiling yet, in terms of the physics, in going to higher and higher energies. What is hindering the building of such machines is the economics! This is not a physical impossibility, but rather a social "impossibility".

I am always skeptical whenever someone, or even a scientist, claim of "maybe" we might reach the end of something, or that we'll never get beyond such-and-such. Again, we seem to have never learned what happened when we claim that, with the state of our knowledge of superconductivity in the early 1980's being a prime example. Almost everyone thought that the field was fully matured, and that there's nothing left to discovery there other than refining our knowledge and the production of the material. Then high-Tc superconductors were discovered and all hell broke loose!

Scientists need to be aware that talks like this can be latched on by the public because news reporters like to over-emphasize the "dramatic" parts. Without intending it, something that many of us know to be still very much a "work in progress" becomes a "fact" to many people outside the field.

Zz.

Quantum Field Theory

So you want to know what "Quantum Field Theory" is? It is not going to be easy, I tell ya!



Zz.

What Makes A Solid .... Well.... Solid?

The title of this Don Lincoln's video is "The Nature of Matter", but I'm re-titling it as "What Makes A Solid Solid", and you'll know why when you watch the video.

Still, while it is informative, what's with the planetary picture of the atom again? I hate to think that we will perpetuate this nasty picture and people who don't know any better will keep holding on with such an understanding.



Zz.

APS Physics Highlights of 2015

APS's Physics lists its highlight stories of 2015.

I need to point out something important that a casual reader might miss. The story on the 3D imaging  of a virus may appear to be an advancement in biology or medical science. And it is, because this allows us to understand a virus better than before. However, it should be pointed out that this capability came into being because of advances in accelerator  science. The imaging was done at SLAC's LCLS, which is a free-electron light source. This involves an advancement FIRST in accelerator science. Only after that are we able to create such a FEL that can produce light sources to do the imaging.

The point I'm trying to make here is that, if you value the field of biology and all the medical advances to help you live better, you should look at how these fields are able to accomplish such a thing. Just look at the National Institute of Health's funding projects, and see how many of them use instruments and facilities that all started out as something a physicist would use. Only later on were they adopted for use in other fields.

So without proper funding and support for the very basic research in physics, which in turn drives not only knowledge, but also the advancement in instrumentation and facilities, these new techniques and technology will not trickle down to the field of biology, chemistry, and medicine.

Zz.