Thursday, July 31, 2014 ... Français/Deutsch/Español/Česky/Japanese/Related posts from blogosphere

Does electron's magnetic field look like that of a bar magnet?

Yes. It's just the laymen's whole way of thinking about it that is wrong.

Brian Bi asked a question on the Physics Stack Exchange,

What does the magnetic field of the (quantum-mechanical) electron look like?
He seems annoyed by the idea that "quantum spinning electrons" have dipole magnetic fields because the magnetic field of a magnetic dipole looks like this:



It's a nice, classical picture of the magnetic field. On the other hand, the spin \(\vec J={\mathbf S}\) of an electron (the arrow above a letter or the bold face represent three-dimensional vectors) is a bizarre quantum observable, an operator. So they can't be proportional, he thinks. Either the formula relating the spin and the magnetic moment\[

\mathbf{\vec\mu} = \frac{g_e \mu_b}{\hbar} \mathbf{S}

\] has to be wrong or we have to deny the formula for the magnetic field (which we may call the "equation under attack")\[

\langle\mathbf{B}({\mathbf{r}})\rangle=\nabla\times{\mathbf{A}}=\frac{\mu_{0}}{4\pi}\left(\frac{3\mathbf{r}(\langle\mathbf{\vec\mu}\rangle\cdot\mathbf{r})}{r^{5}}-\frac{{\langle\mathbf{\vec\mu}\rangle}}{r^{3}}\right),

\] he believes. The idea of the laymen – including all the "interpreters" of quantum mechanics – is that in the microscopic world, the structure of all the equations, shapes of fields have to change but the reasoning stays the same. They think that the microscopic world is described by a "different classical theory".

However, the truth is just the opposite. The microscopic phenomena are described by the "same but quantum theory" as their macroscopic counterparts. Indeed, many equations of motion in quantum mechanical theories may be obtained from the classical ones by adding simple hats above everything (or understanding that they're there without writing them). But the hats often make a lot of deep, conceptual difference.

Unitarity and analyticity say: gravity is the weakest force

In 2006, Arkani-Hamed, Motl, Nicolis, and Vafa presented evidence that gravity is the weakest force, a claim that would often be called the "weak gravity conjecture" (WCG) later. Yes, the swampland on Figure 1, so different from the peaceful Czech landscape, is some territory between Poland, Ukraine, and Belarus. ;-) It means that for any non-gravitational force, imagine the electrostatic or magnetostatic forces, there have to exist light enough particle species that are sufficiently charged so that their mutual non-gravitational forces exceed the gravitational ones.

Be sure that this hypothesis passes the experimental test – gravity is the weakest force in the world around us. But the point is that it couldn't have been otherwise.

This claim – an inequality of a sort – seems to be satisfied everywhere in string theory. Some partial proofs for classes of stringy vacua may be at least sketched. Moreover, even when you ignore any string constructions, the inequality is needed to avoid the black hole remnants which would make any theory of quantum gravity inconsistent. For remnants not to occur, extremal black holes have to be able to decay as well, and by charge and mass conservation laws, that's only possible if the mass/charge ratio of some of the Hawking particles they emit obeys the opposite inequality than the allowed black holes – when the Hawking particles act as "supraextremal black holes" when it comes to their charge/mass ratio.

Criminal character of the sanctions

For more than a decade or so, I have known that most of the EU-level officials are crappy politicians – and crappy human beings, for that matter – but I wouldn't have believed that they would go towards something as insane as a trade war against Russia.

Russia will undoubtedly retaliate but it doesn't even have to.

The point is that trade wars and sanctions always automatically affect both sides. There is a sense in which it is obvious that the overall damages are exactly the same on both sides. Well, one side may have a bigger trouble to replace the "forbidden" business partner with new ones than the other side. But in different cases, it's a different country that has the bigger problem. It's surely not always Russia.

Wednesday, July 30, 2014 ... Français/Deutsch/Español/Česky/Japanese/Related posts from blogosphere

Identical electrons in a nose you touched

Impenetrability of matter proves that generic questions about the intermediate evolution can't have sharp classical answers

Sabine Hossenfelder wrote a playful text

Can you touch your nose?
that partially answers this would-be deep question by philosophers.

You know, you never really touch your nose because there remains a gap between your hand and your nose. The atoms and electrons repel. Sabine correctly says that the Pauli exclusion principle preventing two electrons from being in "exactly the same state" is actually more important for the "impenetrability of matter law" than the Coulomb repulsion. She also correctly discusses that the definition of "you" may be subtle. The electrons and even atoms are constantly leaving and re-entering your body. As Feynman would say, "you" is really the approximate pattern that the particles love to recreate and the approximate dance that they like to dance, not a particular collection of particles.

Also, there may be sparks. When you're tickled by static electricity, you acquire at least several microcoulombs or so which translates to trillions of electrons. Lots of electrons are moving from one surface to another.

Monday, July 28, 2014 ... Français/Deutsch/Español/Česky/Japanese/Related posts from blogosphere

The sleeping beauty problem

Off-topic: Share\(\rm\LaTeX\) has had a facelift, I was told by the folks behind it
Sean Carroll's blog posts are getting stupider and stupider. The latest one is about the
Quantum Sleeping Beauty and the Multiverse
He believes that the blog post is about quantum mechanics or a "quantum version" of a silly problem that philosophers like to answer incorrectly. Of course, there is no quantum mechanics in his musings whatsoever. He hasn't even attempted to think quantum mechanically in his whole life and all his thinking has always been purely classical. In this case, he is thinking about the probabilities in a classical Universe with many worlds and a sleeping forgetful lady in it.



Miss Czechia 2012 Tereza Fajksová in Paris. How many legs does the sleeping beauty in a Škoda car have? I find the obsession of similar (Czech) women with getting the suntan excessive.

Even though it's purely classical, Carroll – along with some stupid philosophers – gives a completely wrong answer to a very trivial problem. What is it?

HL-LHC: 10-tesla shorter magnets are ready

The CERN website printed a cute engineering story about the Fermilab's success this spring:

Next-generation magnets: Small, but powerful
This fall, the Fermilab has shown a prototype of 10.4 tesla magnets.



The high-luminosity (=more collisions per second) large hadron collider (HL-LHC) will need some new collimators etc. and in order to squeeze them over there, one will need magnets that are both shorter and stronger.

To my nations

Guest blog by Franz Joseph I, July 28th '14
Original, JPG

His I&R [imperial and royal; "c. und k." in Czech, "k. und k." in German] Apostolic Majesty descended in order to most graciously publish this Highest blog post and a manifesto written by His own hand:

Dear count Stürgkh


It has been seen to Me to command the minister of My house and the foreign affairs to inform the royal government of Serbia that in between the Monarchy and Serbia the state of war has been initiated.

On this fateful moment I feel the need to turn to my beloved nations. I therefore order you to publicly announce the attached manifesto.

In Bad Ischl [Spa Town in Austria], on July 28th, 1914

Franz Joseph, with His own hand
Stürgkh, with his own hand

Saturday, July 26, 2014 ... Français/Deutsch/Español/Česky/Japanese/Related posts from blogosphere

What Born's rule can't be derived from

Sean Carroll continues to abuse his blog to promote his pseudoscientific would-be research:

Why Probability in Quantum Mechanics is Given by the Wave Function Squared
The article advertises his May 2014 preprint written along with a philosophy student, Charles Sebens. I have already discussed a text by these two authors in Measure for Measure... in May 2014. It turns out that they have written two very similar preprints. Yes, Sebens wrote another earlier paper – the title "Quantum Mechanics As Classical Physics" shows that this guy is hopeless, indeed.

First, sociologically, I think it is very unfortunate if the blogosphere is used for this self-promotion. The scientific community and the scientific public should evaluate the papers and ideas according to their quality and not according to the number of times when they are promoted in distorted blogs on the Internet. The Carroll-Sebens preprints are pure trash which is why, in an ideal world, they would immediately drop into the cesspool and no one would try to extract them again. We don't live in the ideal world. We live in a world where people are massively fed the objects from the cesspools by feeders such as Sean Carroll.

Friday, July 25, 2014 ... Français/Deutsch/Español/Česky/Japanese/Related posts from blogosphere

Brainwashed sheep's obsession with "villain" Vladimir Putin

Several people who largely share my appraisal of the events in Ukraine and around Ukraine have sent me lots of incredible photographs and articles showing that the "mainstream" Western media got completely obsessed with Vladimir Putin.



This 29-year-old lady was threatened by a mayor to be deported from Holland and finally she fled the country by herself – taking BF Jorrit Faasen, 34, with her. In the current hysteria, the sufficient reason is the following: she is Maria Putin, Putin's daughter.

It's enough to search Google News for Putin if you want to obtain a rather incredible collection of totally nutty titles and whole articles about Putin. Just some of the titles (I didn't really have to filter it much):

US General Dempsey: Putin May 'Light a Fire' He Can't Stop in Ukraine

Dempsey: Putin's Moves Like 1939 Poland

Putin's voracious appetite is not sated

Putin’s Pal [a nasty attack against Stephen Cohen]

Putin's inner circle sheds light on his "sinister, lonely life"

The growing calls to strip Putin and Russia of the 2018 World Cup

Putin's Crime, Europe's Cowardice

Vladimir Putin is responsible for shooting down Malaysia Airlines Flight 17. His next move will matter most of all.
I could go on and on and on, for hours. Vladimir Putin is perhaps the next Adolf Hitler, maybe Adolf Hitler on steroids. He must have personally shot the Dutch airplane down, too.

Well, I have been following the Ukrainian events since the late 2013 very closely and one may see that Vladimir Putin hasn't done a damn thing. Perhaps the only thing he did was to do nothing ;-) against the Crimeans' efforts to escape a Ukraine that was conquered by a nationalist hysteria. Needless to say, every other Russian leader – and most leaders of other powers – would do exactly the same thing when their currently threatened, historical region massively asked for re-annexation.

Realistic heterotic non-supersymmetric models

Michael Blaszczyk (we will ultimately teach them to write it as "Blaščik" as any other decent non-Eastern Slavic nation) and three co-authors from German, Greek, and Mexican institutions wrote an interesting paper

Non-supersymmetric heterotic model building
where they show how naturally the \(SO(16)\times SO(16)\) heterotic string theory without supersymmetry is able to produce unifying models with one Higgs doublet, three generations, some logic inherited from non-supersymmetric \(SO(10)\) grand unified theories, and (almost?) nothing beyond the Standard Model at low energies.

Thursday, July 24, 2014 ... Français/Deutsch/Español/Česky/Japanese/Related posts from blogosphere

Gábor Melis' new formidable challenger

Tim Salimans makes the Terminator look like Pokémon

As recently as two hours ago, I thought it was conceivable that I would end up in the top three of the Higgs Kaggle challenge. See the leaderboard.

The top 5 contestants hadn't changed for a week. Gábor Melis was at the top followed by the Marijuana Hybrid guy, by your humble correspondent, and by 1,100+ other participants.



Terminator, Ironman, Batman, and a few Transformers as seen from the optics of a company in Utrecht.

Times are changing. For more than an hour, Tim Salimans of Utrecht, the Netherlands has been the new #2 warrior. His 7th submission with the score 3.81888 catapulted him to that place and made the victory of Gábor Melis uncertain.

Andy Strominger's 74 questions

While at Strings 2014, Clifford Johnson particularly liked one of the "visions talk", the talk by Andy Strominger.

Quantum Gravity and String Theory
Andy gave a realistic i.e. enthusiastic summary of the last three decades in the research of stringy quantum gravity. Most of the advances couldn't have been guessed 30 years ago, Andy observes, and "it is a mistake in science to imagine that you ever know the limits of what we can see", Andy quotes John Kovacs, the BICEP2 boss, who said it at the March 2014 Harvard colloquium.

The amount of progress in the last 30 years really looks impressive with the hindsight.

Wednesday, July 23, 2014 ... Français/Deutsch/Español/Česky/Japanese/Related posts from blogosphere

An interesting interview with Dirac

A few days ago, we talked about Wigner's friend. But who was he?

Edwin Steiner told us about a remarkable interview with Paul Dirac that was done by one of Dirac's few friends (and brothers-in-law), Eugene Wigner, and by Thomas "paradigm shift" Kuhn:

Interview with P. A. M. Dirac By Thomas S. Kuhn and Eugene Paul Wigner At Wigner’s home, Princeton, New Jersey April 1, l962
Spoilers

Dirac talks about the absence of any social life during his childhood. He lived with his parents in an isolated house. The parents didn't sleep with each other and didn't even eat with each other. He could only talk to his father in French. He had one younger and one older sibling. One of them committed suicide at age of 24.

Tuesday, July 22, 2014 ... Français/Deutsch/Español/Česky/Japanese/Related posts from blogosphere

CMS: a \(2.1\TeV\) right-handed \(W_R^\pm\)-boson

Since the beginning of this month, the ATLAS and CMS collaborations have reported several intriguing excesses such as the apparent enhancement of the \(W^+W^-\) cross section (which may be due to some large logarithms neglected by theorists, as a recent paper indicated), a flavor-violating Higgs decay, leptoquarks, and a higgsino excess, among others.

Bizarrely enough, all of us missed another, 2.8-sigma excess exactly one week ago:

CMS: Search for heavy neutrinos and \(W^\pm_R\) bosons with right-handed couplings in proton-proton collisions at \(\sqrt{s} = 8 \TeV\) (arXiv)
The ordinary \(W^\pm\)-bosons only interact with the left-handed component of the electron, muon, and tau, because only those transform nontrivially (as a doublet) under the relevant \(SU(2)_W\) part of the electroweak gauge group.

Monday, July 21, 2014 ... Français/Deutsch/Español/Česky/Japanese/Related posts from blogosphere

Every 300th day in the bulk of a solar cycle is sunspot-free

...they are not that rare...

The Daily Mail is the most influential source that wrote that

Why has the sun gone quiet?

Scientists baffled as sun spots disappear during peak period of solar activity
Surely it must be a miracle that days without any sunspots began last week, inside the Solar Cycle 24. This shouldn't happen, should it? The Sun is going to be turned off, or at least an ice age is coming. But is it? Should we be stunned?



To answer the question, I downloaded the SIDC daily sunspot numbers from a website. Between January 1820 and June 2014, the database provided me with 68,076 daily sunspot numbers. With an 11-year quasiperiod, the sunspot numbers are changing between the minimum near 0 and the maximum between 50-100 or so.

Non-orthogonal quantum states are not mutually exclusive

"Interpreters" of quantum mechanics deny nothing less than Born's rule

In classical physics, if we know that the system has generalized coordinates \((x_i,p_i)\), i.e. that it sits at the corresponding point of the phase space, then we may say that it certainly doesn't have generalized coordinates \((x'_i,p'_i)\) if the collections of numbers differ,\[

(x_i,p_i)\neq (x'_i,p'_i).

\] Different points of the phase space are mutually exclusive even if they are very close to each other. This lesson holds in any classical theory, including classical field theory. If two configurations of a classical field differ as functions\[

\Phi(x,y,z)\neq \Phi'(x,y,z),

\] then we may say with certainty that if the system is found in the configuration \(\Phi(x,y,z)\), then it certainly isn't found in the configuration \(\Phi'(x,y,z)\), not even if the latter is close to the former (but not equal).

The people who are incapable of understanding that the quantum revolution has overthrown the general framework of classical physics almost universally assume that the state vector \(\ket\psi\) in quantum mechanics is a form of a classical variable. They're wrong and their being wrong has very dramatic consequences.

Saturday, July 19, 2014 ... Français/Deutsch/Español/Česky/Japanese/Related posts from blogosphere

CRESST defects from "dark matter is seen" coalition

A year or two years ago, several experiments were claiming the existence of rather similar signals of an apparent dark matter particle lighter than \(10\GeV\). The experimental groups were split almost evenly, to the "Dark Matter Is Seen" allies and the "Dark Matter Is Not Seen" axis.

LUX in South Dakota has totally changed the game 9 months ago and with its precise observations of nothing, it obliterated all the competing experiments that had claimed a signal. Those humiliated "Dark Matter Was Seen" experiments included DAMA, CDMS-Silicon, CoGeNT, and also... CRESST. It didn't become quite clear why they had seen something but with LUX's superiority, it was pretty much guaranteed that what they saw was a mirage i.e. an overlooked or poorly understood systematic effect or background.



As Jester points out, CRESST is no longer an ally and became a LUX-led axis member, too. Incidentally, the LUX experiment itself will be replaced by its king-sized cousin, LUX-ZEPLIN.

Thursday, July 17, 2014 ... Français/Deutsch/Español/Česky/Japanese/Related posts from blogosphere

It's suicidal to fly over New Russia these days

The mysteriously lost MH370 flight of the Malaysian Airlines hasn't been found and there's another tragedy for the company: MH17 from Amsterdam to Kuala Lumpur was shot down near Shakhtar in the Donetsk People's Republic, about 30 miles from the Russian border. The 295 people on board (280 passengers + 15 crew members) died.

I was saddened and shocked at the same moment. People get harassed with all kinds of security regulations but when it comes to the actual trajectories of airplanes, they continue to fly right above the de facto warzone as if nothing were happening over there.

Is time going slowly near the equator?

John Rennie – who is going to jump above me at Physics Stack Exchange in a few months unless I will find motivation to prevent him from doing so – has asked a very nice question:

Does time move slower at the equator?
The Earth is spinning so all people living at the equator are apparently moving at 464 m/s relatively to what seems like a "better inertial frame". By the special relativistic time dilation, this should slow their time by one part per trillion. That would be a 100 larger relative effect than the accuracy you may achieve with state-of-the-art atomic clocks.

Has someone measured this effect that should be measurable?

Christy in NYT, little girl, and school bus

The New York Times have published a relatively friendly story by Michael Wines about John Christy, a well-known climate skeptic:

Though Scorned by Colleagues, a Climate-Change Skeptic Is Unbowed
I say that the article is "relatively friendly" because it pictures Christy as a decent human being and an achieved enough expert while his opponents, the climate alarmists who have contaminated the community of atmospheric scientists, were shown as what they are, a cruel, fanatical, inhumane, Gestapo-like sect that won't even shake Christy's hand.

From an emotional viewpoint, they treat Christy well. However, as James Delingpole nicely discusses, there is some hidden negative message in the article because the author partly intends to legitimize the isolation of Christy in certain circles of his colleagues.