Destruction of a quantum monopole observed

May 17, 2017, Aalto University
Artistic view of the decay of a quantum-mechanical monopole into a Dirac monopole. Credit: Heikka Valja

Scientists at Amherst College (USA) and Aalto University (Finland) have made the first experimental observations of the dynamics of isolated monopoles in quantum matter.

The new study provided a surprise: the decays into another analogue of the magnetic monopole. The obtained fundamental understanding of monopole dynamics may help in the future to build even closer analogues of the .

Unlike usual magnets, magnetic monopoles are elementary particles that have only a south or a north magnetic pole, but not both. They have been theoretically predicted to exist, but no convincing have been reported. Thus physicists are busy looking for analogue objects.

- In 2014, we experimentally realized a Dirac monopole, that is, Paul Dirac's 80-year-old theory where he originally considered charged quantum particles interacting with a magnetic monopole, says Professor David Hall from Amherst College.

- And in 2015, we created real quantum monopoles, adds Dr. Mikko Möttönen from Aalto University.

Whereas the Dirac monopole experiment simulates the motion of a charged particle in the vicinity of a monopolar magnetic field, the quantum monopole has a point-like structure in its own field resembling that of the magnetic monopole particle itself.

View towards the main experimental chamber of the apparatus, showing the magnetic field coils and optical components required to create the superfluid containing the quantum monopole. See instruction above to access the full-resolution image. Figure 3 caption. Credit: Marcus DeMaio/Amherst College

From one quantum monopole to another in less than a second

Now the monopole collaboration led by David Hall and Mikko Möttönen has produced an observation of how one of these unique magnetic monopole analogues spontaneously turns into another in less than a second.

- Sounds easy but we actually had to improve the apparatus to make it happen, says Mr. Tuomas Ollikainen who is the first author of the new work.

The scientists start with an extremely dilute gas of rubidium atoms chilled near absolute zero, at which temperature it forms a Bose-Einstein condensate. Subsequently, they prepare the system in a non-magnetized state and ramp an external magnetic-field zero point into the condensate thus creating an isolated quantum monopole. Then they hold the zero point still and wait for the system to gradually magnetize along the spatially varying magnetic field. The resulting destruction of the quantum monopole gives birth to a Dirac monopole.

- I was jumping in the air when I saw for the first time that we get a Dirac monopole from the decay. This discovery nicely ties together the monopoles we have been producing over the years, says Dr. Möttönen.

Experimental side image of the quantum monopole on the left. After 0.2 seconds, the quantum monopole has decayed into the Dirac monopole shown on the right. The different colors represent the direction of the internal magnetic state of the atoms and the brightness corresponds to particle density. See instructions below to access the full-resolution image. Figure 2 caption. Credit: Tuomas Ollikainen

Beyond Nobel physics

The quantum monopole is a so-called topological point defect, that is, a single point in space surrounded by a structure in the non-magnetized state of the condensate that cannot be removed by continuous reshaping. Such structures are related to the 2016 Nobel Prize in Physics which was awarded in part for discoveries of topological phase transitions involving quantum whirlpools, or vortices.

- Vortex lines have been studied experimentally in superfluids for decades; monopoles, on the other hand, have been studied experimentally for just a few years, says Prof. Hall.

Although its topology protects the quantum monopole, it can decay since the whole phase of matter changes from non-magnetized to magnetized.

- No matter how robust an ice sculpture you make, it all flows down the drain when the ice melts, says Mr. Ollikainen.

- For the first time, we observed spontaneously appearing Dirac monopoles and the related vortex lines, says Dr. Möttönen.

Explore further: Physicists discover quantum-mechanical monopoles

More information: T. Ollikainen, K. Tiurev, A. Blinova, W. Lee, D. S. Hall, and M. Möttönen: Experimental realization of a Dirac monopole through the decay of an isolated monopole. Physical Review X 7. DOI: 10.1103/PhysRevX.7.021023

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21 comments

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Hyperfuzzy
1 / 5 (5) May 17, 2017
You are kidding? magnetism implies current, current implies a loop, so you imply a loop with one side. A one sided loop. That is a path for current around a loop, where the field about the current flow wraps around the path but only half of it exist. The other half is theorized to exist quantum mechanically. Exactly what does that mean? Why? Maybe a field sink on one side. Mono-magnetic pole? You're not making sense, that would be something other than a magnetic pole, juz say'n.
Spaced out Engineer
not rated yet May 17, 2017
So can we be holographers now?
https://arxiv.org.../0602084

I guess anything really is possible with empty.
Whydening Gyre
5 / 5 (1) May 17, 2017
HF.
Usually you're too hyper, but on this one, they're not considering that anything else NOT in the monopolar point as the other pole (or even the CENTER of the point).
Space Out,
A Universe of Infinite possibilities, brother...:-)
Da Schneib
5 / 5 (1) May 18, 2017
It's important to understand that these are not true magnetic monopoles. A real monopole would violate Gauss' Law, ∇⋅B = 0, one of the four equations of Maxwell's Theory. They are an analogous phenomenon in condensed matter physics: https://en.wikipe..._systems

Basically they're the dangling ends of flux tubes formed in materials by magnetic pulses applied at extremely low temperatures, viewed along the axes of the tubes.
Dingbone
May 18, 2017
This comment has been removed by a moderator.
Hyperfuzzy
not rated yet May 18, 2017
HF.
Usually you're too hyper, but on this one, they're not considering that anything else NOT in the monopolar point as the other pole (or even the CENTER of the point).
Space Out,
A Universe of Infinite possibilities, brother...:-)

Nonsense, not infinite stupidity, say anything, even if it is disproved by its own character.
Hyperfuzzy
not rated yet May 18, 2017
HF.
Usually you're too hyper, but on this one, they're not considering that anything else NOT in the monopolar point as the other pole (or even the CENTER of the point).
Space Out,
A Universe of Infinite possibilities, brother...:-)

Nonsense, not infinite stupidity, say anything, even if it is disproved by its own character.

Magnetic poles are defined by Maxwell as the instrumentation, and the image; however, the description lacks an axiomatic structure; therefore, without logic. Anyway, circular argument; you may say anything based upon any known events, or upon events never seen, or implied, or can be constructed or measured, ... juz say'n, imagination. You don't want to war with Logic, Sanity? These items,in science, have a description; QM is lucky, undefined event, not a , ah WTF
Whydening Gyre
not rated yet May 18, 2017
HF.
Usually you're too hyper, but on this one, they're not considering that anything else NOT in the monopolar point as the other pole (or even the CENTER of the point).
Space Out,
A Universe of Infinite possibilities, brother...:-)

Nonsense, not infinite stupidity, say anything, even if it is disproved by its own character.

Hunh?!? You sayin' I'm nonsensical or infinitely stupid? Or that my character is dis-approvable?
Whydening Gyre
not rated yet May 18, 2017
HF.
Usually you're too hyper, but on this one, they're not considering that anything else NOT in the monopolar point as the other pole (or even the CENTER of the point).
Space Out,
A Universe of Infinite possibilities, brother...:-)

Nonsense, not infinite stupidity, say anything, even if it is disproved by its own character.

Magnetic poles are defined by Maxwell as the instrumentation, and the image; however, the description lacks an axiomatic structure; therefore, without logic. Anyway, circular argument; you may say anything based upon any known events, or upon events never seen, or implied, or can be constructed or measured, ... juz say'n, imagination. You don't want to war with Logic, Sanity? These items,in science, have a description; QM is lucky, undefined event, not a , ah WTF

Again - Hunh?!?
Hyperfuzzy
not rated yet May 19, 2017
HF.
Usually you're too hyper, but on this one, they're not considering that anything else NOT in the monopolar point as the other pole (or even the CENTER of the point).
Space Out,
A Universe of Infinite possibilities, brother...:-)

Nonsense, not infinite stupidity, say anything, even if it is disproved by its own character.

Hunh?!? You sayin' I'm nonsensical or infinitely stupid? Or that my character is dis-approvable?

No, I try not to be insulting; however, when I see a description with the same logical appearance of "This sentence is false." am i T or F? False premise, observation of a physical impossibility, why not. Both false, therefore True. same as "I'm lying!"
Hyperfuzzy
not rated yet May 19, 2017
HF.
Usually you're too hyper, but on this one, they're not considering that anything else NOT in the monopolar point as the other pole (or even the CENTER of the point).
Space Out,
A Universe of Infinite possibilities, brother...:-)

Nonsense, not infinite stupidity, say anything, even if it is disproved by its own character.

Hunh?!? You sayin' I'm nonsensical or infinitely stupid? Or that my character is dis-approvable?

No, I try not to be insulting; however, when I see a description with the same logical appearance of "This sentence is false." am i T or F? False premise, observation of a physical impossibility, why not. Both false, therefore True. same as "I'm lying!"
Da Schneib
not rated yet May 19, 2017
Jeez, @HF said that? Really?

More to the point, it was typed on a computer? Which only works because of Maxwell's Equations?

Duh.
Hyperfuzzy
not rated yet May 20, 2017
Jeez, @HF said that? Really?

More to the point, it was typed on a computer? Which only works because of Maxwell's Equations?

Duh.

T or F?
Da Schneib
not rated yet May 20, 2017
@HF, you said:
Magnetic poles are defined by Maxwell as the instrumentation, and the image; however, the description lacks an axiomatic structure; therefore, without logic.
I have no idea what you mean when you claim they "lack an axiomatic structure." B (the magnetic field) is an axiom of Maxwell's Equations. So is E (the electric field). As for being "without logic," that's handwaving; they're mathematical equations, dude. They obey mathematical logic.

I can't even imagine what you're thinking when you say things like this. They're so completely disconnected from reality as to be completely meaningless.
Hyperfuzzy
1 / 5 (1) May 20, 2017
@HF, you said:
Magnetic poles are defined by Maxwell as the instrumentation, and the image; however, the description lacks an axiomatic structure; therefore, without logic.
I have no idea what you mean when you claim they "lack an axiomatic structure." B (the magnetic field) is an axiom of Maxwell's Equations. So is E (the electric field). As for being "without logic," that's handwaving; they're mathematical equations, dude. They obey mathematical logic.

I can't even imagine what you're thinking when you say things like this. They're so completely disconnected from reality as to be completely meaningless.

Sorry, poorly stated. The magnetic pole and its polarity also describes a current loop; best said, a changing E field. magnetism is derivative. Yeah, "as the instrumentation" as also to Maxwell's definitions, mathematically, empirically. Thanks
Hyperfuzzy
not rated yet May 20, 2017
@HF, you said:
Magnetic poles are defined by Maxwell as the instrumentation, and the image; however, the description lacks an axiomatic structure; therefore, without logic.
I have no idea what you mean when you claim they "lack an axiomatic structure." B (the magnetic field) is an axiom of Maxwell's Equations. So is E (the electric field). As for being "without logic," that's handwaving; they're mathematical equations, dude. They obey mathematical logic.

I can't even imagine what you're thinking when you say things like this. They're so completely disconnected from reality as to be completely meaningless.

Sorry, poorly stated. The magnetic pole and its polarity also describes a current loop; best said, a changing E field. magnetism is derivative. Yeah, "as the instrumentation" as also to Maxwell's definitions, mathematically, empirically. Thanks

Axiom: Charge exists, spatial and time derivatives, individual, ... gravity; QM ?
Da Schneib
not rated yet May 20, 2017
There's no need for current or charges in ∇⋅B = 0. So actually it's not "poorly stated" at all. And that one equation shows there cannot be monopoles. They'd be magnetic charges, and charges can't satisfy ∇⋅B = 0.

Sorry? Yes. Very.
Hyperfuzzy
not rated yet May 20, 2017
There's no need for current or charges in ∇⋅B = 0. So actually it's not "poorly stated" at all. And that one equation shows there cannot be monopoles. They'd be magnetic charges, and charges can't satisfy ∇⋅B = 0.

Sorry? Yes. Very.

anyway F = q[E + vXB] therefore necessary and sufficient conditions, to even get a measure, is at least motion, ok what's moving, juz say'n
Dingbone
May 20, 2017
This comment has been removed by a moderator.
Da Schneib
not rated yet May 20, 2017
@HF, your notation makes no sense. A single charge doesn't have a force on it unless there's another charge. You appear to be claiming that charges encounter some magical force by moving. It doesn't work like that.
Da Schneib
not rated yet May 20, 2017
@Dingbat, close enough that the computer you typed that on works fine.

As for ∇⋅B = 0, how about you show us all how monopoles can exist in a gravity field. Good luck with that.

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