Science

Novel artificial neurons learn independently and are more strongly modeled on their biological counterparts. A team of researchers has programmed these infomorphic neurons and constructed artificial neural networks from them. The special feature is that the individual artificial neurons learn in a self-organized way and draw the necessary information from their immediate environment in the network.

The US has confirmed more than 480 measles cases across 19 states, the highest total since an outbreak in 2019 sickened more than 1200 people

No matter where on Earth you stand, if you have a view of the night sky, and if it is dark enough, you can see the Milky Way. The Milky Way is our home, and its faint clouds of light and shadow have inspired human cultures across the globe. And yet, our view of the Milky Way is limited by our perspective. In many ways, we have learned more from other galaxies than from our own. But when the Gaia spacecraft launched in 2013, all of that changed.

In this age of exoplanet discovery, the flaring of red dwarf stars (M-dwarfs) has taken on new importance. M-dwarfs are known to host many terrestrial planets in their putative habitable zones. The problem is the flaring could make their habitable zones uninhabitable.

Between reading science stuff that I’m going to write about elsewhere, and my pleasure reading of a mammoth book (not one about the woolly mammoth!), I don’t have many books to report on. In fact, I’m about to be at a loss for books to read, and thus will tell you what I’ve read as a way of extracting suggestions from readers.

For a while I was on a Holocaust kick, and (as I think I mentioned earlier) I read The End of the Holocaust, by Alvin Rosenfeld, which you can get from Amazon by clicking below. His thesis is that the true horror of the Holocaust has been lessened by everyone using the word to mean “any bad thing that happened to a lot of people.” The book is especially concerned with Anne Frank, who, he says, was just one of a number of young victims who wrote about their situation, and somehow the attention devoted to her alone lessens the experience of other victims. Well, you can argue about that, but I think the book is worth reading now that words like “genocide,” “concentration camp,” and “Holocaust” are being thrown around willy nilly in a way that distorts their original meaning.

After that I read another short but very famous book about the Holocaust, Night, by Elie Wiesel. Click below to see the Amazon link:

Wiesel, a Romanian-born Jew, was taken to the camps with his family when he was young, and managed to survive two of them, writing several books about his experiences (this one, like the others, is either partly fictional or completely fictional but Night is mostly true). Wiesel was separated from his mother and sisters at Auschwitz-Birkenau, and they did not survive (they were probably gassed). Throughout the book he tries to stay with his father and keep him alive, but the father finally expires on a forced, foodless march through the snow as the prisoners are marched to another camp by the Germans as the Russians approach. Wiesel survived, but just barely.

After the war, Wiesel dedicated himself to writing and lecturing about the Holocaust, and won the Nobel Peace Prize in 1986.  Night is one of the best books about the Holocaust, at least in conveying its horrors, and was recommended by Rosenfeld in the book above. I too recommend it highly, and, at 120 pages, it’s a short read.

Here’s a photo of Buchenwald five days after its liberation by the Red Army, showing the arrangement of bunks and the skeletal nature of those still alive. Wiesel is in the photo; I’ve circled him next to one bed post. What better proof can you have that you really did experience what you wrote about?

Buchenwald concentration camp, photo taken April 16, 1945, five days after liberation of the camp. Wiesel is in the second row from the bottom, seventh from the left, next to the bunk post. From Wikimedia Commons

And below is the behemoth I just finished, Wolf Hall by Hilary Mantel, which won both the Booker Prize and the National Book Circle Award in 2009. Click the cover to go to the Amazon site.

Several people recommended this book highly, and while I think the 730-page monster was very good, I didn’t find it a world classic. It recounts the life of Thomas Cromwell, who started life as the son of a blacksmith but worked his way up to being the head minister of Henry VIII. It deals largely with the intrigues and relationships of Henry’s court, which reminds me of Trump’s America.  Henry was sometimes amiable, but would ruthlessly order the death of those who crossed him, including Anne Boleyn, who met her end simply because she couldn’t provide Henry with a son that could be his heir.  Sir Thomas More is a prominent character, and he too meets his end for refusing to affirm that Anne Boleyn was the lawful queen. Everyone tiptoes around in constant fear of the KIng.

The book is quite involved, and has a big list of characters which are listed on the first page and to which one must constantly refer. It is the convoluted plot and surfeit of characters that made the book hard for me to read. Perhaps I’m getting old and my concentration is waning.  But the dialogue is fascinating, and parts of the book are quite lyrical, with the prose style changing quickly from conversational to rhapsodic. Here’s what Wikipedia says about Mantel’s writing of the book, and the effort shows.

Mantel said she spent five years researching and writing the book, trying to match her fiction to the historical record. To avoid contradicting history she created a card catalogue, organised alphabetically by character, with each card containing notes indicating where a particular historical figure was on relevant dates. “You really need to know, where is the Duke of Suffolk at the moment? You can’t have him in London if he’s supposed to be somewhere else,” she explained.

In an interview with The Guardian, Mantel stated her aim to place the reader in “that time and that place, putting you into Henry’s entourage. The essence of the thing is not to judge with hindsight, not to pass judgment from the lofty perch of the 21st century when we know what happened. It’s to be there with them in that hunting party at Wolf Hall, moving forward with imperfect information and perhaps wrong expectations, but in any case, moving forward into a future that is not pre-determined but where chance and hazard will play a terrific role.”

The book (part of a trilogy) was made into a mini-series for t.v., and here’s the trailer. It feature Cromwell, Cardinal Wolsey, Anne Boleyn, and Henry VIII. Has anyone seen it?

So that’s my reading. Now I ask readers to recommend books for me—and other readers. They can be fiction or nonfiction, so long as they’re absorbing.  I’m not sure I’m yet ready now for another 700-page novel (Amazon’s version says only 600-odd pages, but I have an older edition).  Please put your recommendations, as well as the subject of the book, in the comments.

Clothes that can mimic the feeling of being touched, touch displays that provide haptic feedback to users, or even ultralight loudspeakers. These are just some of the devices made possible using thin silicone films that can be precisely controlled so that they vibrate, flex, press or pull exactly as desired. And all done simply by applying an electrical voltage.

Clothes that can mimic the feeling of being touched, touch displays that provide haptic feedback to users, or even ultralight loudspeakers. These are just some of the devices made possible using thin silicone films that can be precisely controlled so that they vibrate, flex, press or pull exactly as desired. And all done simply by applying an electrical voltage.

Leveraging the power of AI and machine learning technologies, researchers developed a more effective model for predicting how patients with muscle-invasive bladder cancer will respond to chemotherapy. The model harnesses whole-slide tumor imaging data and gene expression analyses in a way that outperforms previous models using a single data type.

Researchers have uncovered a more efficient way to turn carbon dioxide into methanol, a type of alcohol that can serve as a cleaner alternative fuel.

Astronomers have used the James Webb Space Telescope to observe asteroid 2024 YR4, which earlier this year seemed to be at risk of hitting Earth in 2032. Earth is now safe, but astronomers are cheering on a possible collision with the moon

There are a number of ways that exoplanets have been discovered over recent years but a team of astronomers have been exploring other ways. One particular exciting method is to hunt for them by finding their magnetospheres! Earth and Jupiter are a great example of planets that are surrounded by strong magnetospheres that interact with solar activity and when they do, they release radio emissions. The team of researchers have been demonstrating just how they could detect Jupiter’s radio emissions using simulated data. Not only would they be able to detect it, but they could also measure its rotation and even detect interactions with its moons!

The quantum double-slit experiment, in which objects are sent toward and through a pair of slits in a wall,and are recorded on a screen behind the slits, clearly shows an interference pattern. It’s natural to ask, “where does the interference occur?”

The problem is that there is a hidden assumption in this way of framing the question — a very natural assumption, based on our experience with waves in water or in sound. In those cases, we can explicitly see (Fig. 1) how interference builds up between the slits and the screen.

Figure 1: How water waves or sound waves interfere after passing through two slits.

But when we dig deep into quantum physics, this way of thinking runs into trouble. Asking “where” is not as straightforward as it seems. In the next post we’ll see why. Today we’ll lay the groundwork.

Independence and Interference

From my long list of examples with and without interference (we saw last time what distinguishes the two classes), let’s pick a superposition whose pre-quantum version is shown in Fig. 2.

Figure 2: A pre-quantum view of a superposition in which particle 1 is moving left OR right, and particle 2 is stationary at x=3.

Here we have

• particle 1 going from left to right, with particle 2 stationary at x=+3, OR
• particle 1 going from right to left, with particle 2 again stationary at x=+3.

In Fig. 3 is what the wave function Ψ(x1,x2) [where x1 is the position of particle 1 and x2 is the position of particle 2] looks like when its absolute-value squared is graphed on the space of possibilities. Both peaks have x2=+3, representing the fact that particle 2 is stationary. They move in opposite directions and pass through each other horizontally as particle 1 moves to the right OR to the left.

Figure 3: The graph of the absolute-value-squared of the wave function for the quantum version of the system in Fig. 2.

This looks remarkably similar to what we would have if particle 2 weren’t there at all! The interference fringes run parallel to the x2 axis, meaning the locations of the interference peaks and valleys depend on x1 but not on x2. In fact, if we measure particle 1, ignoring particle 2, we’ll see the same interference pattern that we see when a single particle is in the superposition of Fig. 1 with particle 2 removed (Fig. 4):

Figure 4a: The square of the absolute value of the wave function for a particle in a superposition of the form shown in Fig. 2 but with the second particle removed. Figure 4b: A closeup of the interference pattern that occurs at the moment when the two peaks in Fig. 4a perfectly overlap. The real and imaginary parts of the wave function are shown in red and blue, while its square is drawn in black.

We can confirm this in a simple way. If we measure the position of particle 1, ignoring particle 2, the probability of finding that particle at a specific position x1 is given by projecting the wave function, shown above as a function of x1 and x2, onto the x1 axis. [More mathematically, this is done by integrating over x2 to leave a function of x1 only.] Sometimes (not always!) this is essentially equivalent to viewing the graph of the wave function from one side, as in Figs. 5-6.

Figure 5: Projecting the wave function of Fig. 3, at the moment of maximum interference, onto the x1 axis. Compare with the black curve in Fig. 4b.

Because the interference ridges in Fig. 3 are parallel to the x2 axis and thus independent of particle 2’s exact position, we do indeed find, when we project onto the x1 axis as in Fig. 5, that the familiar interference pattern of Fig. 4b reappears.

Meanwhile, if at that same moment we measure particle 2’s position, we will find results centered around x2=+3, with no interference, as seen in Fig. 6 where we project the wave function of Fig. 3 onto the x2 axis.

Figure 6: Projecting the wave function of Fig. 3, at the moment of maximum interference, onto the x2 axis. The position of particle 2 is thus close to x2=3, with no interference pattern.

Why is this case so simple, with the one-particle case in Fig. 4 and the two-particle case in Figs. 3 and 5 so closely resembling each other?

The Cause

It has nothing specifically to do with the fact that particle 2 is stationary. Another example I gave had particle 2 stationary in both parts of the superposition, but located in two different places. In Figs. 7a and 7b, the pre-quantum version of that system is shown both in physical space and in the space of possibilities [where I have, for the first time, put stars for the two possibilities onto the same graph.]

Figure 7a: A similar system to that of Fig. 2, drawn in its pre-quantum version in physical space. Figure 7b: Same as Fig. 7a, but drawn in the space of possibilities.

You can see that the two stars’ paths will not intersect, since one remains at x2=+3 and the other remains at x2=-3. Thus there should be no interference — and indeed, none is seen in Fig. 8, where the time evolution of the full quantum wave function is shown. The two peaks miss each other, and so no interference occurs.

Figure 8: The absolute-value-squared of the wave function corresponding to Figs. 7a-7b.

If we project the wave function of Fig. 8 onto the x1 axis at the moment when the two peaks are at x1=0, we see (Fig. 9) a single peak (because the two peaks, with different values of x2, are projected onto each other). No interference fringes are seen.

Figure 9: At the moment when the first particle is near x1=0, the probability of finding particle 1 as a function of x1 shows a featureless peak, with no interference effects.

Instead the resemblance between Figs. 3-5 has to do with the fact that particle 2 is doing exactly the same thing in each part of the superposition. For instance, as in Fig. 10, suppose particle 2 is moving to the left in both possibilities.

Figure 10: A system similar to that of Fig. 2, but with particle 2 (orange) moving to the left in both parts of the superposition.

(In the top possibility, particles 1 and 2 will encounter one another; but we have been assuming for simplicity that they don’t interact, so they can safely pass right through each other.)

The resulting wave function is shown in Fig. 11:

Figure 11: The absolute-value-squared of the wave function corresponding to Fig.10.

The two peaks cross paths when x1=0 and x2=2. The wave function again shows interference at that location, with fringes that are independent of x2. If we project the wave function onto the x1=0 axis, we’ll get exactly the same thing we saw in Fig. 5, even though the behavior of the wave function in x2 is different.

This makes the pattern clear: if, in each part of the superposition, particle 2 behaves identically, then particle 1 will be subject to the same pattern of interference as if particle 2 were absent. Said another way, if the behavior of particle 1 is independent of particle 2 (and vice versa), then any interference effects involving one particle will be as though the other particle wasn’t even there.

Said yet another way, the two particles in Figs. 2 and 10 are uncorrelated, meaning that we can understand what either particle is doing without having to know what the other is doing.

Importantly, the examples studied in the previous post did not have this feature. That’s crucial in understanding why the interference seen at the end of that post wasn’t so simple.

Independence and Factoring

What we are seeing in Figs. 2 and 10 has an analogy in algebra. If we have an algebraic expression such as

• (a c + b c),

in which c is common to both terms, then we can factor it into

• (a+b)c.

The same is true of the kinds of physical processes we’ve been looking at. In Fig. 10 the two particles’ behavior is uncorrelated, so we can “factor” the pre-quantum system as follows.

Figure 12: The “factored” form of the superposition in Fig. 10.

What we see here is that factoring involves an AND, while superposition is an OR: the figure above says that (particle 1 is moving from left to right OR from right to left) AND (particle 2 is moving from right to left, no matter what particle 1 is doing.)

And in the quantum context, if (and only if) two particles’ behaviors are completely uncorrelated, we can literally factor the wave function into a product of two functions, one for each particle:

• Ψ(x1,x2)=Ψ1(x1)Ψ2(x2)

In this specific case of Fig. 12, where the first particle is in a superposition whose parts I’ve labeled A and B, we can write Ψ1(x1) as a sum of two terms:

• Ψ1(x1)=ΨA(x1) + ΨB(x1)

Specifically, ΨA(x1) describes particle 1 moving left to right — giving one peak in Fig. 11 — and ΨB(x1) describes particle 2 moving right to left, giving the other peak.

But this kind of factoring is rare, and not possible in general. None of the examples in the previous post (or of this post, excepting that of its Fig. 5) can be factored. That’s because in these examples, the particles are correlated: the behavior of one depends on the behavior of the other.

Superposition AND Superposition

If the particles are truly uncorrelated, we should be able to put both particles into superpositions of two possibilities. As a pre-quantum system, that would give us (particle 1 in state A OR state B) AND (particle 2 in state C OR state D) in Fig. 13.

Figure 13: The two particles are uncorrelated, and so their behavior can be factored. The first particle is in a superposition of states A and B, the second in a superposition of states C and D.

The corresponding factored wave function, in which (particle 1 moves left to right OR right to left) AND (particle 2 moves left to right OR right to left), can be written as a product of two superpositions:

• Ψ(x1,x2)=Ψ1(x1)Ψ2(x2) = [ΨA(x1)+ΨB(x1)] [ΨC(x2)+ΨD(x2)]

In algebra, we can expand a similar product

• (a+b)(c+d)=ac+ad+bc+bd

giving us four terms. In the same way we can expand the above wave function into four terms

• Ψ(x1,x2)=ΨA(x1)ΨC(x2)+ΨB(x1)ΨC(x2)+ΨA(x1)ΨD(x2)+ΨB(x1)ΨD(x2)

whose pre-quantum version gives us the four possibilities shown in Fig. 14.

Figure 14: The product in Fig. 13 is expanded into its four distinct possibilities.

The wave function therefore has four peaks, one for each term. The wave function behaves as shown in Fig. 15.

Figure 15: The wave function for the system in Fig. 14 shows interference of two pairs of possibilities, first for particle 1 and later for particle 2.

The four peaks interfere in pairs. The top two and the bottom two interfere when particle 1 reaches x1=0, creating fringes that run parallel to the x2 axis and thus are independent of x2. Notice that even though there are two sets of interference fringes when particle 1 reaches x1=0 in all the superpositions, we do not observe this if we only measure particle 1. When we project the wave function onto the x1 axis, the two sets of interference fringes line up, and we see the same single-particle interference pattern that we’ve seen so many times (Figs. 3-5). That’s all because particles 1 and 2 are uncorrelated.

Figure 16: The first instance of interference, seen in two peaks in Fig. 15 is reduced, when projected on to the x1 axis, to the same interference pattern as seen in Figs. 3-5; the measurement of particle 1’s position will show the same interference pattern in each case, because particles 1 and 2 are uncorrelated.

If at the same moment we measure particle 2 ignoring particle 1, we find (Fig. 17) that particle 2 has equal probability of being near x=2.5 or x=-0.5, with no interference effects.

Figure 17: The first instance of interference, seen in two peaks in Fig. 15, shows two peaks with no interference when projected on to the x2 axis. Thus measurements of particle 2’s position show no interference at this moment.

Meanwhile, the left two and the right two peaks in Fig. 15 subsequently interfere when particle 2 reaches x2=1, creating fringes that run parallel to the x1 axis, and thus are independent of x1; these will show up near x=1 in measurements of particle 2’s position. This is shown (Fig. 18) by projecting the wave function at that moment onto the x2 axis.

Figure 18: During the second instance of interference in Fig. 15, the projection of the wave function onto the x2 axis. Locating the Interference?

So far, in all these examples, it seems that we can say where the interference occurs in physical space. For instance, in this last example, it appears that particle 1 shows interference around x=0, and slightly later particle 2 shows interference around x=1.

But if we look back at the end of the last post, we can see that something is off. In the examples considered there, the particles are correlated and the wave function cannot be factored. And in the last example in Fig. 12 of that post, we saw interference patterns whose ridges are parallel neither to the x1 axis nor to the x2 axis. . .an effect that a factored wave function cannot produce. [Fun exercise: prove this last statement.]

As a result, projecting the wave function of that example onto the x1 axis hides the interference pattern, as shown in Fig. 19. The same is true when projecting onto the x2 axis.

Figure 19: Alhough Fig. 12 of the previous post shows an interference pattern, it is hidden when the wave function is projected onto the x1 axis, leaving only a boring bump. The observable consequences are shown in Fig. 13 of that same post.

Consequently, neither measurements of particle 1’s position nor measurements of particle 2’s position can reveal the interference effect. (This is shown, for particle 1, in the previous post’s Fig. 13.) This leaves it unclear where the interference is, or even how to measure it.

But in fact it can be measured, and next time we’ll see how. We’ll also see that in a general superposition, where the two particles are correlated, interference effects often cannot be said to have a location in physical space. And that will lead us to a first glimpse of one of the most shocking lessons of quantum physics.

One More Uncorrelated Example, Just for Fun

To close, I’ll leave you with one more uncorrelated example, merely because it looks cool. In pre-quantum language, the setup is shown in Fig. 20.

Figure 20: Another uncorrelated superposition with four possibilities.

Now all four peaks interfere simultaneously, near (x1,x2)=(1,-1).

Figure 21: The four peaks simultaneously interfere, generating a grid pattern.

The grid pattern in the interference assures that the usual interference effects can be seen for both particles at the same time, with the interference for particle 1 near x1=1 and that for particle 2 near x2=-1. Here are the projections onto the two axes at the moment of maximal interference.

Figure 22a: At the moment of maximum interference, the projection of the wave function onto the x1 axis shows interference near x1=1. Figure 22b: At the moment of maximum interference, the projection of the wave function onto the x2 axis shows interference near x2=-1.

Reader James Blilie has returned with some recent photos of California. James’s captions are indented, and you can enlarge the pictures by clicking on them. The road he traveled down is my favorite one in the U.S., and, I think, the most scenic. I used to travel it when I went from Davis, CA. to Death Valley to collect flies.

Here is a set from our trip to the southern California desert in January 2025.

We again traveled down US 395 through eastern California to the Palm Desert area for some warmth and sunlight to break up the Pacific Northwest winter.  We returned up I-5 through California to Weed, California where we turned off onto US Hwy 97 through eastern Oregon.

These are mostly landscape photos, which is my thing.  As you can tell from the photos, we were lucky with the weather.

Descending to Mono Lake from Conway Summit:

Moonrise over the White Mountains from the Owens River valley, near Bishop, California:

Mount Whitney range from near Lone Pine, California (also in the Owens Valley):

A shot from hiking in the Andreas Canyon, near Palm Springs, California.  The canyons in the San Jacinto range above Palm Springs have flowing rivers and are full of life:

Next are two shots from a hike in Joshua Tree National Park.  Mojave Yucca (Yucca schidigera) and Teddy Bear Cholla (Cylindropuntia bigelovii).  Both of them shouting at you:  “don’t touch!”:

Next are two shots from the Thousand Palms Oasis.  An overview of the site, which has thousands of California Fan Palms (Washingtonia filifera) and then a show of the palm foliage:

Then a few shots from our homeward journey.

At a rest area on northbound I-5 in the Central Valley of California, we found olive trees growing with lots of fallen fruit underneath them.  (Olea europaea):

Mount McLoughlin and Upper Klamath Lake at dawn (Oregon):

Equipment:

Olympus OM-D E-M5 (micro 4/3 camera, crop factor = 2.0)
LUMIX G X Vario, 12-35mm, f/2.8 ASPH.  (24mm-70mm equivalent)
LUMIX 35-100mm  f/2.8 G Vario  (70-200mm equivalent)
LUMIX G VARIO 7-14mm f/4.0 ASPH

The long-standing question of how animals came to have an anus may have been solved by studies of which genes are active during development in various animals

When the James Webb Space Telescope was launched in December 2021, one of its primary purposes was to see the first galaxies in the Universe forming just a few million years after the Big Bang. In true JWST style though, it has surpassed all expectations and now, a team of astronomers think they have gone even further back, seeing one galaxy clearing the early fog that obscured the Universe! The image represents a point in time 330 million years after the Big Bang and reveals a bright hydrogen emission from the fog surrounding a galaxy. It was somewhat unexpected though as current models predict it would have been blown away long ago!

The outer planets remain somewhat of a mystery and Neptune is no exception. Voyager 2 has been the only probe that has visited the outermost planet but thankfully the James Webb Space Telescope is powerful enough to reveal it in all its glory. With its cameras regularly fixed on Neptune it has even picked up auroral activity in some of its latest images. The data was gathered back in 2023 using Webb’s Near-Infrared spectrograph which detected the tell tale sign of auroral activity, an emission line of trihydrogen cation. The element appears on other giant planets too when aurora are present.

Some researchers propose that countries should start to rack up a carbon debt once they exceed their carbon budget, obliging them to do more to draw down carbon dioxide, but the idea is unlikely to form part of international climate agreements

We Told You So: Vaccines Cause Autism And So Many Other Really Bad Things

The post Science Based Satire: A Sneak Preview Of RFK Jr.’s Vaccine-Autism Study first appeared on Science-Based Medicine.

Can the cosmic rays bombarding the lunar surface be used to identify subsurface water ice deposits? This is what a recent study and iposter presented at the 56th Lunar and Planetary Science Conference (LPSC) hopes to address as a team of researchers developed a novel method called the Cosmic Ray Lunar Sounder (CoRaLS) capable of detecting subsurface lunar water ice deposits that are elusive to current radar systems. This study has the potential to help expand the human presence on the Moon since water ice deposits are currently being focused on the permanently shadowed regions (PSRs) of the Moon for the upcoming Artemis missions.

When researchers asked people to work on a computer with their phones 1.5 metres away, the amount of time they spent on their phone went down – but they just scrolled social media on their laptop instead