Pictures of Hawking Successfully Experiencing A Brief History of Weightlessness

OK, maybe ONE more article on this thing. We all know that Stephen Hawking successfully made a trip in the vomit comet and experiences a few moments of weightlessness. Well know, we have pictures.

Just so you know, the pictures aren't pretty. :)

Zz.

Are You A Quack?

It is no secret that I have very little patience for people who spew ideas based on ignorance. Reading my series of essays on "Imagination Without Knowledge is Ignorance Waiting to Happen" would convince you of that. What is even worse is that these are some of the most suborn people around who simply refuse, probably out of laziness or even stupidity, to learn the physics that they are trying to either debunk or even "theorize". Such an practice occurs a lot more with the popularity of the internet.

In response to such attacks on physics, several physicists have produced websites to highlight the fallacies and silliness of these people and the "theories" they spew. I have already mentioned the weekly column done by Bob Park that frequently jibe at some really bad practices done by individuals, institutions, and even government agencies. He also has an article written a while back titled "The Seven Warning Signs of Voodoo Science". This was probably the precursor to his book. It certainly puts in very concise form all the warning signs that one could use to detect cranky ideas and actions.

In a more comical approach to addressing the crackpots, Warren Siegel at SUNY Stony Brook has ready-made responses to the most common complaints/whines/attacks addressed to him by these jokers in his Are You A Quack page. I think anyone who has been on the internet forums for any considerable length of time would have seen a few, if not all, of these types of comments. It gets very tiring because each one of these quacks thinks he/she is special and the first one to have uttered such words. Don't miss the note towards the very end of that webpage:

Note: Long ago a professor of mine told me that he got letters from 2 quacks, so he forwarded each's letter to the other. He got back an angry letter from one saying, "Why did you introduce me to this quack?"

That's just plain hysterical. I've always wondered why these quacks don't go after each other FIRST before bringing such crap to physicists. I guess it's honor among thieves.

Zz.

So You Want To Be A Physicist

I wrote earlier on here about the series of on-going essay that I have written that appears on a couple of online places. The problem with these sources is that the essays are fragmented in different locations. Since I wrote them over a period of time, they all don't appear in one continuous fashion. Many people have suggested that I find a place to put all of them in a contiguous document. I didn't find the time to do that, till now.

I have collected all of them, and made a few revisions here and there, and the essay can now be found easily in one single document. It can also be found as one of the Physics link for this blog.

Note that it is still isn't finished, and there are still plenty of typo and grammatical errors. I also will make several revision and changes to it continually, so check the date of the last revision.

If you find any errors or have any suggestions, please send them to me.

Zz.

Just 120 Trillion Miles From Home

This New York Times article explores the means and the difficulties of visiting the newest celestial system discovered to contain an earth-like planet.

It's a daunting task to get there, and we certainly do not have the propulsion technology yet to realisticallly achieve that.

Zz.

One-Handed Balancing Serving Tray

OK. This is NOT meant to push this item and create a sale for Hammerchar-Schlemmer. But this is such a cool-looking gadget. It is a serving tray that you can balance with just one hand. It's one of those things that can easily pass as a physics demonstration for the principle of center of mass or center of gravity.

Still, does it really have to cost THAT much? $69.95 is a bit steep for a tray with a handle sticking out at just the right angle, isn't it?

Zz.

Hands-On Fun With Physics Includes Some Brain Puzzlers

Here's another touring physics exhibit that making its appearance at the Pima County Fair in Arizona.

The exhibit features daily demonstrations that focus on Newton's three laws of motion and involve key vocabulary words in physics, such as gravity, inertia, mass, matter and cylindrical force.

Er... cylindrical force? Key words in physics?

Anyway, I think it is a very good idea to have exhibits like this at a county fair, where more of the general public that would not make the effort to go to science fair or schools open house might actually visit just out of curiosity.

Zz.

Quantum Cryptography Hacked

Well, so much for the security argument for quantum cryptography. Physicists at MIT has managed to "hack" into a network (limited time open link) protected by quantum encryption.[1]

..... a group from the Massachusetts Institute of Technology (MIT) in Cambridge was able to 'listen in' using a sort of quantum-mechanical wiretap. The trick allowed them to tease out about half of the data, in a way that couldn't be detected by those transmitting or receiving the message.

Still, all is not lost.

To grab the information en-route would require a 'quantum non-demolition box' - a theoretically possible but as-yet-unbuilt device that could measure the photon and pass it along. "What they have done is a simulation of an attack, not a real one," says Lo.

Shapiro and Wong agree. And they add that a quantum cryptographic network can be simply tweaked to beat their attack. By making the key out of a lot of photons instead of just a few, the sender and receiver could ensure that the eavesdropper never got enough of the key to use it. Still, they say, the work shows that secrets — even quantum ones — are never entirely safe.

Zz.

[1] Kim T., et al. Phys. Rev. A, v.75 p.042327 (2007).

Hawking Successfully Experienced A Brief Period of Weightlessness

Since we've been following this since it first started, we might as well conclude it with the successful attempt of Stephen Hawking to experience weightlessness first hand.

A doctor and three nurses monitored Hawking throughout the Zero Gravity Corp. flight. The scientist floated in the air, free of his wheelchair and electronic communication gear for the first time in 40 years.

After the jet reached its proper altitude, Hawking's assistants lifted him out of his seat and laid him on his back in the front of the cabin for the first plunge.

Good for him!

Zz.

Entanglement Sudden Death

There is a very fascinating paper in Science this week.

M.P. Almeida et al. "Environment-Induced Sudden Death of Entanglement", Science v.316, p.579 (2007).

Abstract: We demonstrate the difference between local, single-particle dynamics and global dynamics of entangled quantum systems coupled to independent environments. Using an all-optical experimental setup, we showed that, even when the environment-induced decay of each system is asymptotic, quantum entanglement may suddenly disappear. This "sudden death" constitutes yet another distinct and counterintuitive trait of entanglement.

A perspective on this paper, written by Eberly and Yu, is also in the same issue of Science.

They have devised an elegantly clean way to check and to confirm the existence of so-called "entanglement sudden death" (ESD) (7), a two-body disentanglement that is novel among known relaxation effects because it has no lifetime in any usual sense--that is, entanglement terminates completely after a finite interval, without a smoothly diminishing long-time tail.

But what was more interesting, at least to me (and I'm still reading the paper the 2nd time trying to understand this), is this part of that perspective article:

It is often implied and sometimes said explicitly, in textbooks as well as in physics colloquia, that our evidence for the quantum character of natural phenomena comes from the existence of wave-particle duality in the microworld. But this is misleading at best. Wave mechanics is just optics for particles, and it contains effects no more exotic than are found in physical optics (rays, diffraction, tunneling, etc.). In striking contrast, quantum mechanics exhibits features that have no classical wave counterpart at all. Duality is no help in understanding the entangled nature of Schrödinger's Cat, which "exists" in a strange entangled state, equally likely dead and alive (19-21).

To investigate quantitatively the time development of a property such as the degree of entanglement of two or more quantum systems is to enter what is probably the largest nonclassical sector of the world we live in, and the report by Almeida et al. brings new evidence to bear on these questions. They have used a photonic Cat: a pair of qubits (quantum bits in the form of photon polarizations) whose degree of mutual entanglement they can study in the clear absence of mutual interaction. Each of these photonic qubits interacts only with its own individual environment, and this produces smooth dephasing of each individual photon's polarization angles. But this provides very misleading guidance to a quantitative understanding of the photons' Cat-like properties. One-body information about the photons is useless to explain the sudden death of their entanglement.

This is interesting because I have several entries on Schrodinger Cat-type states and measurements. While this is not quite the same thing, it would be interesting to see where they match.

Zz.

Hawking To Experience A Brief History of Weightlessness Today

As reported earlier, Stephen Hawking is going up in the "vomit comet" and experience a few brief moment of weightlessness. That event will take place today!

I wonder if he will still be attached to his wheelchair?

Zz.

Revamped Experiment Could Detect Axions?

At least these physicists think so. They are proposing a revamping of a number of current experiment to significantly increase the chance of detecting axions. The experiment is essentially "shining light through walls"

The unimproved experiment seeks to detect axions by shining a laser down the bore of a powerful superconducting magnet. A wall in the middle stops the laser cold, with the theoretical axions continuing through the wall and into the other side of the magnet. There, the magnet reconverts them into photons, or particles of light.

The detection of this light “reappearing” on the other side of the wall is what gives the experiment its iconic name.

Researchers in the U.S. and Europe are in various stages of conducting the experiment. The activity has been stimulated by a recent Italian experiment that claims to have discovered axion-like particles. The hope is to confirm the Legnaro National Laboratories’ results or take them a step further.

Sikivie, UF physics professor David Tanner and Karl van Bibber, a physicist at the Lawrence Livermore National Laboratory, propose a redesign of the “shining light through walls” experiment to make it, in their words, “vastly more sensitive.”

I'll try to update this later with the exact citation of the paper. So far, it doesn't show up yet on the PRL website. The only reference to anything similar is a paper by almost the same group of people published in 2005[1]. There is, however, an ArXiv preprint on this, and presumably, this is the paper[2].

Zz.

[1] Phys. Rev. Lett. 95, 091304 (2005).
[2] http://arxiv.org/abs/hep-ph/0701198.

Cosmologically Speaking, Diamonds May Actually Be Forever

Maybe girls know more than guys about this, but there's a good reason why you would want diamonds to be your best friend. This news article reports on, and interviews both Lawrence Krauss and Robert Scherrer on their recent paper.

Writing in the journal Physical Review D, the two physicists show that matter as we know it will remain as the universe expands at an ever-increasing clip. That is, the current status quo between matter and its alter ego, radiation, will continue as the newly discovered force of dark energy pushes the universe apart.

This paper was titled Radiation can never again dominate matter in a vacuum dominated universe[1] and the abstract is below:

We demonstrate that in a vacuum-energy-dominated expansion phase, surprisingly neither the decay of matter nor matter-antimatter annihilation into relativistic particles can ever cause radiation to once again dominate over matter in the future history of the Universe.

Zz.

[1] Phys. Rev. D 75, 083524 (2007).

Water Flows Like Molasses on the Nanoscale

Scientists at Georgia Tech has discovered that when confined to a width of less than 2 nanometers, water flows with a viscosity equivalent to molasses.

"Since water usually has a low viscosity, the force you would expect to feel as you compress it should be very small," said Riedo, assistant professor in Georgia Tech's School of Physics. "But when we did the experiment, we found that when the distance between the tip and the surface is about one nanometer, we feel a repulsive force by the water that is much stronger than what we would expect."

There are many things that do not really behave in the same fashion as you change its dimensionality. Take for instance, charge carriers that we are so familiar with. In 3D, ordinary metals behave in the "usual" fashion, and typically can be accurately described by Landau's Fermi Liquid Theory. However, try confining it to 1D. Then these charge carriers (be it electrons or holes) will start behaving in very unusual manner. The weakest possible interaction between themselves could possibly produce what is known as the spin-charge separation. This is where the spin and charge properties appear to "flow" differently, as if the charge carrier has split itself into 2 components, one that carries the spin, while the other carries the charge.

This is purely a many-body effect in 1D, and can be described by the Tomonaga-Luttinger Liquid model. However, it again illustrates that simply by changing the dimensionality, the physics can be VERY different. Now this also ties in with my previous "rants" about the bastardization of quantum mechanics. There seems to be a free-wheeling idea that some understanding in one area can be EASILY extrapolated into another. People are applying QM into human interactions, or using Relativity to justify social policies, etc. All of these people are exhibiting the classical symptom that I've called "imagination without knowledge is ignorance waiting to happen". What it means is that they took the superficial knowledge of certain physics principles, but are completely ignorant of other parts of physics that simply cannot be isolated from such principles. For example, there is a very important area of physics called "phase transition". This is the study where a system undergoes an ABRUPT CHANGE in one or more properties as goes through that transition. Water turning into ice is an example. A metal going into a superconductor is another example. Its resistivity drops abruptly to zero as it goes just below the transition temperature Tc. It isn't a gradual process. But what is more important is that the behavior and temperature dependence of the resistivity above Tc cannot be extrapolated all the way down to, say, T=0, because the characteristics of the resistivity is very different below and above Tc. When things undergo a phase transition, this is what happens. You cannot assume that the behavior in one phase is the same as the behavior in another phase.

Now, if that is the case, then what is there to say that one can actually extrapolate what we know for systems obeying quantum mechanical behavior to, let's say, a human interaction scale? There's nothing that say we can. There's no indication that social and collective human behavior are "quantum systems". When people use physics principles and extrapolate them into such scales, they are only aware of those "sexy" ideas of physics while ignoring the fact that physics are often aware of when such extrapolations can and cannot be applied. They should also take what we have learned from the study of phase transition and be aware that not everything can be extrapolated that easily.

Zz.

Hopes Dim for Perfect Lens

This could be a major setback for those working in trying to perfect "lenses" using the negative refraction phenomenon. A theorist has published a paper (link is open to all only for a limited time) arguing that there is an inherent problem with such a device - substantial absorption that cannot be overcome with current metamaterial structure.

Mark Stockman, a theoretical physicist at Georgia State University, argues that...

The electrons in the materials slosh in response to the electromagnetic fields in the light, and causality says that the precise arrangement and motion of the electrons can depend on light that has already passed through them--not on the light that has yet to arrive. Starting from that point, Stockman has shown mathematically that negative refraction and absorption are intertwined so that you cannot have one without the other, as he reports in a paper to be published in Physical Review Letters. "There is no way to decrease the losses," Stockman says. "The [negative refraction] effect will disappear." In particular, simple amplification won't do the trick, he says.

Of course, this will not stop others working in this field to either prove him wrong, or find a way around this.

Zz.

Hip-Hop Meets Physics

A rather inventive way to introduce physics and make it more "interesting", I think.

It is commendable that there are many people who are trying things to teach and raise interst in science, and physics in particular. However, is there a careful study and follow-up to see if such a thing is really effective? This is probably not that easy to do, but it would be nice to know that such activities do make an impact, rather than just a fun diversion/entertainment (nothing wrong with that).

Zz.

To Boldly Do What No Laser Has Done Before

This is an informative article of the LINAC Coherent Light Source (LCLS) that is being built at SLAC. The world-famous high-energy physics facility is being "retrofitted" to become a "light source" and transforming itself from a particle collider to a user facility to generate light to be used to study other things.

Zz.

Presenting the Sun - in 3D!

It seems that everyone nowadays is getting into the 3D business, especially after Disney has gotten into it big time with Chicken Little, the re-release of Nightmare Before Christmas, and the recently-released Meet the Robinsons. It seems that NASA has has caught on with the 3D fever. It has released the image of the sun - in 3D!

Of course, you need a pair of 3D glasses to view this. And no, the 3D glasses you get when viewing those Disney Digital 3D movies would not work here - I tried! :)

Zz.

First Black Woman to Earn a Ph.D. in Physics in Colorado

At this day and age, something like this should no longer be a news item, but unfortunately, it is. It reflects the very small percentage of African-American, and especially female African-American getting a Ph.D in physics.

I don't know how much she has to persevere to get to this point, but she certainly deserves a BIG congratulations.

Zz.

QM Says Goodbye to Reality?

This was the "big" news of the week in physics. A paper by the Zeilinger's group in Austria has made a test that rules out large classes of "realism" model that could not be saved even when locality is relaxed. The test of the Leggett's inequality, which is an extension of the Bell inequality, has made QM even more verified than before.

This is a rather interesting paper because, till now, the Bell-type experiments can only violate "local realism", but are not able to distinguish if they violate either "locality", "realism", or both. Locality is the interconnectedness of entangled properties no matter how far they are in space. A measurement on one instantaneously affects the other. Realism is an idea that a system actually have definite properties moving with it locally even when we haven't measured it. The latter is what makes this purely quantum mechanical and the basis of Schrodinger's infamous cat thought experiment.

The more they test it, the more convincing it becomes....

Zz.

More Brian Greene Interview

This guy is in the news almost as much as Stephen Hawking! :)

This time, Greene is being interviewed because he was brought in as a "consultant" for the upcoming movie Deja Vu, one of the upcoming Jerry Bruckheimer movie. So read it and weep. You probably won't see physics being discussed on a movie website anytime soon!

Zz.