A new effect in electromagnetism discovered – 150 years later

October 23, 2017, IBM Blog Research
Fig. (a) The “camelback” field confinement effect in the parallel dipole line (PDL) system. (b) The IBM PDL magnetic trap system. A graphite rod gets trapped and levitates perpetually without any input power. (d) A member of The Netherlands Physics Olympiad Team, Julian Sanders, performing an experiment with the IBM PDL trap in The 2017 International Physics Olympiad. Credit: IBM Blog Research

Electromagnetism is a branch of physics that deals with all phenomena of electricity and magnetism. This field is the key foundation of our modern age of electricity and information technology. It is governed by a set of fundamental principles encoded in four equations called Maxwell equations, which have been known for approximately 150 years. Every time we harness fundamental effects as prescribed or predicted by this theory, we reap immense benefits in terms of technological advances. Things like electric machines, motors, various electronics devices, circuits, computers, display, sensors and wireless communication all operate based on the basic principles of electromagnetism. This subject is actually considered "classical physics," which seems to suggest that we have known everything we need to know about it.

However, our IBM Research team recently discovered a subtle hidden feature in electromagnetism—a previously unknown field confinement effect that we've named the "camelback effect" in a system of two lines of transverse dipoles.

In electromagnetism, the elementary source of electric field and magnetic field can be respectively modeled as a point charge—a hypothetical charge located at a single point in space—and a dipole, a pair of equal and oppositely charged or magnetized poles separated by a distance. Imagine we line up two rows of magnetic dipoles as shown in Fig (a), and we try to measure the strength of the magnetic field along the center axis. The is certainly stronger at the center and diminishes away from it. However, if the length of the dipole line exceeds certain critical length, a surprising effect occurs: the field gets slightly stronger near the edges and produces a field confinement profile that looks like a camel's back—hence the name of the effect. The IBM team has reported this discovery with detailed experimental and theoretical studies in two recent publications and patents.

This surprising discovery is exciting for a few reasons. First, it represents a new elementary one-dimensional confinement potential in physics, joining the list of well-known potentials such as Coulomb, parabolic, and square well. Second, this effect becomes the key feature that enables this system to serve as a new class of natural called parallel dipole line (PDL) trap as shown in Fig. (b) with many possible exciting applications. This camelback effect and the related PDL magnetic trap can be realized using special cylindrical magnets whose poles are on the curved side as shown in Fig. (b) and a graphite rod as the trapped object.

This natural magnetic trap also demonstrates "particle-in-one dimensional potential" system, thus serving as a novel platform for pedagogical physics experiments. For this reason, after a rigorous selection process, the IBM discovery was recently featured as an experimental problem in the International Physics Olympiad (IPhO) recently held in Yogyakarta, Indonesia in July. IPhO is a premier international physics competition at pre-college level which has been running since 1967 (first held in Warsaw, Poland). Each participating country sends their top five physics students to compete in solving three theoretical and two experimental problems. The problems presented are typically very challenging and original and, more importantly, they must present fundamental ideas or concepts in physics.

In this year's IPhO, about 396 students from 86 countries—one of the largest IPhO ever—performed experiments using the IBM PDL magnetic trap to determine the magnetic property of the trapped graphite and the air viscosity. The students also investigated its applications as earthquake and volcanic tiltmeter sensor. This is actually an ongoing project between IBM Research and the Italian Institute of Geophysics and Volcanology (INGV). The overall exposition was appreciated by the international team leaders for its novel, fascinating and rich physics content as well as its noble applications.

This IBM magnetic trap research has now been included as a new lecture note material in Electrodynamics course in Princeton University. It has also produced practical technology as a new high sensitivity semiconductor characterization tool called "Rotating PDL Hall system" that has served many groups in IBM Research that work with semiconductors. It has also been operating at the Harvard Center of Nanoscale System laboratory.

On a side note, the international impact of this work for physics pedagogy is rather unexpected, as the research was originally intended for semiconductor technology development. The IBM team were exploring ways to trap tiny cylindrical objects like nanowires for next generation transistors. Nevertheless, the adoption of our research work in a premier international event, such as IPhO, exemplifies our mission in IBM Research "to be famous for our science and vital to the world."

Explore further: JILA spinning method confirms the electron still seems round

More information: O. Gunawan, Y. Virgus, and K. Fai Tai, A parallel dipole line system, Appl. Phys. Lett. 106, 062407 (2015).

O. Gunawan and Y. Virgus, The one-dimensional camelback potential in the parallel dipole line trap: Stability conditions and finite size effect, J. Appl. Phys. 121, 133902 (2017).

O. Gunawan and Q. Cao, "Magnetic trap for cylindrical diamagnetic materials," U.S. patent 8,895,355 (2014); 9,093,377 (2015); 9,236,293 (2016); 9,263,669 (2016); 9,424,971 (2016).

K. T. McDonald, Diamagnetic Levitation, (Princeton University) www.hep.princeton.edu/~mcdonal … ples/diamagnetic.pdf.

Long Rod with Uniform Magnetization Transverse to its Axis www.physics.princeton.edu/~mcd … /examples/magrod.pdf

Rotational stability of a diamagnetic rod
physics.princeton.edu/ mcdonald/examples/diamagnetic_rotation.pdf

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11 comments

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KBK
1 / 5 (5) Oct 23, 2017
Of course, artificial ones have been talked about in anti gravity device reports for many decades.

But, until it entered the dogma, it was considered a bunch of hooey from a pack of weirdos and charlatans.

Careful with the dogma trap, it will destroy the future.

When will people learn?
rrwillsj
2.3 / 5 (3) Oct 24, 2017
Uhh, K, are you claiming that gravity and electro-magnetism are the same fundamental force?

And calling electro-magnetic polar repulsion "anti-gravity" does not make it so.

If you would want to perform an experiment proving that claim? Take a a pair of five pound magnets. Wrestle their matching poles as close together as your strength holds out. Until you drop them on your foot!

'nough said.
Whydening Gyre
5 / 5 (2) Oct 24, 2017
Uhh, K, are you claiming that gravity and electro-magnetism are the same fundamental force?

And calling electro-magnetic polar repulsion "anti-gravity" does not make it so.

If you would want to perform an experiment proving that claim? Take a a pair of five pound magnets. Wrestle their matching poles as close together as your strength holds out. Until you drop them on your foot!

'nough said.

If you're going all Spidey on us, it's actually "nuff said."...
Per yer experiment;
Just imagine those magnets at atomic scale in a 0 gravity environment. Multiply them by a trillion. Start them spinning(slow is fine to start). Now, keep adding more and more, a trillion or so at a time.
Think they'll all just line up in a dipolar fashion...?
Do you think they'll attract other materials in a dipolar fashion?
jwinter
1 / 5 (1) Oct 24, 2017
There is nothing special or new about this effect. Stable static levitation of diamagnetic materials such as graphite is commonplace and even a live frog has been levitated. What is initially unexpected for this configuration is that the field is weaker in the centre when theory says it should be strongest there. But this is readily explained by the demagnetising field which is strongest in the middle and weaker at the ends. This effect has either caused these long magnets to lose some magnetisation in the central regions, or caused these regions to not have been initially magnetised to the same degree as the ends. If they were uniformly magnetised there would be no potential well. This same effect occurs with a thin flat disk magnetised along its axis in that the perimeter is easier to magnetise and keeps its magnetisation better than the centre. People working with magnetic materials use spheroidal shaped samples so that the internal demagnetising field is uniform over the volume.
Whydening Gyre
5 / 5 (2) Oct 25, 2017
There is nothing special or new about this effect. Stable static levitation of diamagnetic materials such as graphite is commonplace and even a live frog has been levitated. What is initially unexpected for this configuration is that the field is weaker in the centre when theory says it should be strongest there. But this is readily explained by the demagnetising field which is strongest in the middle and weaker at the ends. ... People working with magnetic materials use spheroidal shaped samples so that the internal demagnetising field is uniform over the volume.

DE-magnetizing field...?!?
They're magnets! Just to the left or right of the exact center is where it weakest in it's ability to be opposed to the opposite polarity.
(Loved your version of Jumpin' Jack Flash, btw...)
jwinter
1 / 5 (1) Oct 25, 2017
DE-magnetizing field...?!?

Look it up and educate yourself. Google is your friend.
jwinter
1 / 5 (1) Oct 25, 2017
... If they were uniformly magnetised there would be no potential well...

This is not true. The demagnetising field from the ends of the magnet does indeed reduce the total field strength in the middle so that there will be a potential well if the magnet is long and thin enough.
rrwillsj
1 / 5 (2) Oct 25, 2017
WG, the takeaway from my comment is that Electro-Magnetism and Gravity are not the same fundamental force. Equating E-M repulsion, an empirically proven phenomena, as being proof of fraudulent Anti-Gravity claims.

In my opinion anti-gravity is impossible. No matter how well depicted in comicbooks and F/Xed video. Any competent stage illusionist can conjure items to float in midair, It still ain't A-G!

If I dream, that every poker hand I am dealt is going to come up a Royal Flush? Each and every hand? And bet accordingly?

A: would you think I had stacked the deck or mechanic the cards?
B: Would you lend me your rent money to bet?
C: Would you wrestle the pipe of hash from my slackjaw?
D: Would you suggest electro-shock therapy or a lobotomy?

As for the research outlined in this article. I have no argument with what they have accomplished. Or with their future intentions at developing upon their novel findings.
Whydening Gyre
5 / 5 (1) Oct 26, 2017
WG, the takeaway from my comment is that Electro-Magnetism and Gravity are not the same fundamental force. Equating E-M repulsion, an empirically proven phenomena, as being proof of fraudulent Anti-Gravity claims.

Not the same, but they have the same beginning.
In my opinion anti-gravity is impossible.

What about null gravity?
If I dream, that every poker hand I am dealt is going to come up a Royal Flush? Each and every hand? And bet accordingly?

A: would you think I had stacked the deck or mechanic the cards?
B: Would you lend me your rent money to bet?
C: Would you wrestle the pipe of hash from my slackjaw?
D: Would you suggest electro-shock therapy or a lobotomy?

Hey, it's YOUR dream. Don't ask me...:-)
rrwillsj
1 / 5 (2) Oct 27, 2017
Null-Gravity? No, don't think so.

Gravity is a Constant of Mass. Little as a bug, as big as a Galactic Cluster. The exact same attractant, just different in scale. One degree Centigrade is the same heat energy, as is a hundred degrees Centigrade.

Any machine that is constructed to reverse Gravity? Would also reverse the Gravitational Force of it's own material mass. Right down to the sub-atomic level. Messy.

KA-BOOM!!!

Please perform this experiment someplace else. Somewhere far, far away? I suggest Proxima Centauri. We might be able to see the flash from here, if you time it right.

Ohhh, Petty Lights!!
PPihkala
not rated yet Nov 03, 2017
"It is governed by a set of fundamental principles encoded in four equations called Maxwell equations"

Is is wonder that magnetism is not understood, when we only use 4 of the original 20 equations of Maxwell?
http://www.chenie...well.htm

How well would mathematics do today if somebody would have forgot anything else than addition, substraction, multiplication and division. No one is going to need imaginary numbers either...

Now when we have machines to calculate even complex equations, electromagnetism should be studied based on all of those 20 equations of Maxwell. But asymmetrical fields 'are not needed' so they were ignored >100 years ago, hiding all kinds of effects from practical use.

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