Got mass? Scientists observe electrons become both heavy and speedy

Jun 13, 2012
Electrons moving in certain solids can behave as if they are a thousand times more massive than free electrons, but at the same time act as superconductors. A new study led by Princeton scientists shows that this happens because of a process known as quantum entanglement that determines the mass of electrons moving in a crystal. The discovery can help improve understanding of how certain materials become superconducting, which may have applications in areas such as power network efficiency and computing speed. Credit: the Yazdani Group

A Princeton University-led team of scientists has shown how electrons moving in certain solids can behave as though they are a thousand times more massive than free electrons, yet at the same time act as speedy superconductors.

The observation of these seemingly contradictory changes in the electron properties is critical to the understanding of how certain materials become superconducting, in which can flow without resistance. Such materials could dramatically increase the efficiency of electrical power networks and speed up computers.

The concept of "heavy" electrons seems counterintuitive. The flit through to process information rapidly in digital electronics, and they flow with ease through carrying electricity to your desk lamp. But the Princeton research has revealed that a hard-to-measure process known as quantum entanglement determines the mass of electrons moving in a crystal and the delicate tuning of this entanglement can strongly alter the properties of a material.

Cool the electrons to far below room temperature in certain types of , and these flighty particles gain mass, acting like much heavier particles. Surprisingly, further cooling close to absolute zero makes these solids become superconducting, where the electrons, despite their heaviness, make a kind of perfect fluid that can flow without wasting any electrical power.

This video is not supported by your browser at this time.
This video displays heavy electrons at different energies and shows their standing wave patterns (like water in a pond) around individual atomic defects placed intentionally in a compound. The patterns in these images allowed the Princeton scientists to understand the formation of heavy electron waves and to identify a hard-to-measure quantum entanglement process that controls their mass. Credit: The Yazdani Group.

In a study to appear in the June 14 issue of the journal Nature, the Princeton-led team, which included scientists from Los Alamos National Laboratory (LANL) and the University of California-Irvine, used direct imaging of in a crystal. The researchers did so not only to watch the electrons gain mass but also to show that the heavy electrons are actually composite objects made of two entangled forms of the electron. This entanglement arises from the rules of , which govern how very small particles behave and allow entangled particles to behave differently than untangled ones. Combining experiments and theoretical modeling, the study is the first to show how the heavy electrons emerge from such entanglement.

Observations made over the last 30 years indicate that electrons in certain solids behave as particles with masses hundreds to thousands of times larger than that of electrons moving freely in a vacuum. Until now, however, researchers had been unable to understand how this happens and lacked the tools to explore the connection between this process and the superconductivity of heavy electrons.

The published study comes after several years of setting up the precise experimental conditions needed to visualize these heavy electrons. The team employed a custom-designed cryogenic scanning tunneling microscopy (STM), which allows visualization of electron waves in a crystal. The researchers used STM to look at crystals prepared in such a way that their surfaces contained a few atomic imperfections. As they lowered the temperature in the experiment, the researchers saw the emergence of patterns of electron waves spread around the defects in a way similar to how ripples of water form around rocks in a pond. (See video.)

"It is remarkable to watch electrons moving in a crystal evolve into more massive particles as we cool them down," said Ali Yazdani, a professor of physics at Princeton and head of the team that conducted the study.

Making this groundbreaking observation of electrons as they transition from light to heavy particles is only part of the story. The researchers also showed how the process can be understood based on quantum theories of electron behavior. Subatomic particles such as electrons can exhibit strange behavior because of , which can mix diametrically opposite behaviors together. By comparing the data with theoretical calculations, the study shows that heavy electrons emerge from entanglement of two opposite behaviors of electrons, one in which they are localized around individual atoms and the other in which they are hopping freely from atom to atom in the crystal.

"This is the first time we have a precise picture of formation of heavy electrons, thanks to our ability to probe them with high resolution," Yazdani said.

The degree of such entanglement appears to be the key to understanding what the heavy electrons do once they are formed and cooled even further. Adjusting the crystal composition or structure can be used to tune the degree of entanglement and the heaviness of electrons. Make the electrons too heavy and they freeze into a magnetized state, stuck at each atom in the crystal while spinning in unison. But tweaking the crystal composition so that the electrons have just the right amount of entanglement turns these heavy electrons into superconductors when they are cooled.

"What is neat, and our studies confirm this, is that you really need to be on the verge of these two kinds of behaviors — sluggish and speedy — to get superconductivity," Yazdani said. "That is the circumstance most favorable to occurrence of heavy electron superconductivity."

Understanding superconducting behavior of exotic electrons is at the forefront of research in physics, where there are many examples of magnetic materials that turn superconducting with subtle changes in their composition or crystal structure.

The experiments may help physicists unravel the mysteries of high-temperature superconductivity, said Subir Sachdev, a theoretical physicist at Harvard University who was not involved with the work. Many physicists have argued that understanding this transition between magnetism and superconductivity, known as a quantum critical point, could help explain why the materials are superconducting. But physicists have lacked experimental evidence to prove their ideas.

"We have been waiting for observations like this for many years, so it is very exciting that such a beautiful experimental system has been found and characterized so well," Sachdev said.

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gwrede
1.2 / 5 (6) Jun 13, 2012
If we have a brick where electrons enter at one end, gain mass, are accelerated towards the other end, are stripped of the extra mass, and then finally decelerated an exited from the brick, to be recycled, we would have an exhaust-free propulsion system for space travel.

At a smaller scale, this could be used for aiming satellites, instead of reaction wheels. This would be a more durable solid-state solution.

Terriva
1 / 5 (2) Jun 13, 2012
With respect to the effective mass of charge carriers we can distinguish two kinds of materials: LIGHT and HEAVY fermion materials. The light fermion materials (typically graphene and all superconductors, where the effective mass of electrons goes to zero) can be imagined like the hydrophobic teflon sponge soaked with mercury. The electrons are compressed between atoms into spaces in such a way, a motion of one electron induces the motion of many others IN THE SAME DIRECTION like at the case of wagons in the train, which are colliding and moving like the wave.

The heavy fermion materials use the opposite trick. They're similar to hydrophilic sponge with flat channels, where the electrons are moving like the people in the narrow street or corridors: when some wants to pass the street, some other electron(s) must clear its way first and they do move in DIRECTION, WHICH IS PERPENDICULAR to the motion of primary electron. This effect increases effective mass of movable electrons a lot.
Cave_Man
1.4 / 5 (5) Jun 13, 2012
So does this mean that initiating a chemical reaction inside of a lattice material could be more than a chemical reaction due to nucleonic forces like this newly discovered electron transition. If so LENR seem much more plausible.
Terriva
1 / 5 (2) Jun 13, 2012
In brief, the heavy electrons are electrons, the motion of which requires the acceleration of many other electrons in perpendicular direction. The light electrons are electrons, the motion of which induces the acceleration of many other electrons along the line parallel to the direction of their motion. Because in the perpendicular motion of electrons across atoms the highly eccentric f-orbitals are involved, the heavy electrons are often forming f-wave superconductors from the bottom side of periodic table (plutonium), whereas the light electron materials are forming s-wave and p-wave superconductors with atoms, where movable electrons are residing at s- and p-orbitals along the axis of atom connection lines (cuprates). The pnictides are materials of mixed s- and d-wave superconductivity.
Terriva
1 / 5 (2) Jun 13, 2012
If so LENR seem much more plausible.
IMO LENR is based on Mossbauer lattice effect and the discussion of its mechanism doesn't belong here. It's difficult to achieve the formation of sparks with shaking of lightweight sand grains inside of closed vessel. But when we shake the heavier pebbles, then the kinetic energy of their collisions may be sufficient for formation of sparks. I can imagine, under rare geometry the atoms are getting aligned in line, so they're colliding like big compact clusters, the inertia of which is sufficient to overcome the Coulombic barrier. The Astroblaster toy (Galilean cannon) effect may apply there.
baudrunner
2.1 / 5 (7) Jun 13, 2012
Einstein: mass increases as velocity increases toward asymptote (c on the Y axis). Superconducting electrons have greater velocity than room temperature electrons, ergo increased mass. It's simple.

Construence of observation is based on desire to see manifestation of Higgs Boson conferring mass to particles theorem, which is BOGUS. Analysis of the result is tainted thereby.
Phil DePayne
3.3 / 5 (3) Jun 13, 2012
Perhaps someone use this information to step beyond mere entanglemnent to electron teleportation, and to be the first to teleport a particle with mass.
MrVibrating
5 / 5 (4) Jun 13, 2012
@gwrede - a clarification is in order here; "effective mass" is a term used in condensed matter physics with a different meaning to conventional mass. I made the same leap when reading that "electron mass goes to zero in graphene" - immediately thought of a copper/graphene N3 violation and ended up thrashing it out on the forums here...

..so yeah, unfortunately i was reliably informed it's not the same kind of mass... (perhaps someone more knowledgeable can elucidate further?)
Vendicar_Decarian
1 / 5 (1) Jun 13, 2012
Meuon catalyzed fusion.
Deesky
5 / 5 (1) Jun 13, 2012
Construence of observation is based on desire to see manifestation of Higgs Boson conferring mass to particles theorem, which is BOGUS.

Why is it bogus? What do you know that the experts don't?

Burnerjack
not rated yet Jun 13, 2012
So if electrons have mass, and that effective mass is velocity dependent, relevisticaly, as Baudrunner pointed out, does this mean also that electrons have a gravitational field, albeit, modulating as well?
dtyarbrough
1 / 5 (2) Jun 13, 2012
When free electrons are slowed, they increase their spin (conservation of momentum) and create larger magnetic fields(gain physical mass). Cooling them slows their vibration allowing them to be more easily detectable. Speed within a solid is due to external forces and does not reduce the spin as it would if they moved under their own power. The larger mass when subjected to external forces (which are stronger due to their larger magnetic field) can move more easily through matter.
Howhot
not rated yet Jun 14, 2012
Forgive me if this is an ignorant question, but does this mean that a Cooper Pair is a quantum entangled electron pair?

Vendicar_Decarian
3 / 5 (2) Jun 14, 2012
You confuse conservation of angular momentum with conservation of momentum.

"When free electrons are slowed, they increase their spin" - dtyarTard

Fail.

Electron spin is quantized and always comes in units of plus or minus 1/2

Double Fail.
dtyarbrough
1 / 5 (1) Jun 14, 2012
You confuse conservation of angular momentum with conservation of momentum.
Make that conservation of energy which includes both types of momentum.- Vendictive Decardian
PussyCat_Eyes
1 / 5 (1) Jun 14, 2012
Vendicar....just wanted to let you know that CardacianNeverid aka TheGhostofOtto1923 is using your "Tard" trademark in the other thread, pretending to be you. LOL
Vendicar_Decarian
5 / 5 (1) Jun 14, 2012
If an electron's mass is effectively increased by a factor of 1000, and a muon's mass is effectively 200 times that of an electron and if muon catalyzed fusion is possible with muons then on this basis it may be possible with seemingly heavy electrons.

LENR anyone?
Vendicar_Decarian
not rated yet Jun 14, 2012
Energy and momentum are not the same and one does not derive from the other.

"Make that conservation of energy which includes both types of momentum" - dfyarbrough

Triple Fail.
Satene
1 / 5 (1) Jun 14, 2012
does this mean that a Cooper Pair is a quantum entangled electron pair
Yes, but the additional forces (spin-spin interactions) take place here. The purely quantum entangled state is a way brittler and it was observed with neutral particles only so far.
does this mean also that electrons have a gravitational field, albeit, modulating as well
When the heavy electron is moving trough lattice of heavy fermion material, many other electrons travel with it, their masses and gravitational field are therefore additive. But this mass is virtual only, as the animation illustrates and it doesn't increase the total mass of the lattice.
MrVibrating
not rated yet Jun 14, 2012
..so.. still awaiting a clearer answer on why this variable mass doesn't imply an inertial drive mechanism..?? Ie. make a mass of electrons heavier in one direction and lighter in the other, and an AC current should produce thrust..

Obviously this is a misconception, but why, exactly?
TkClick
1 / 5 (1) Jun 14, 2012
why this variable mass doesn't imply an inertial drive mechanism
Because its symmetrical and the heavy electrons are heavy from all directions? The trouble is just in the making the electrons "heavier in one direction and lighter in the other", which is nonsense, as the mass is scalar concept. It's similar misconception like the "directional time", i.e. the time running with speed dependent on the direction, in which we are looking at it...
MrVibrating
not rated yet Jun 14, 2012
Perhaps i should explain further - the electron mass is constantly changing direction (as AC current) - while transiting between two different materials - say a conventional conductor like copper and one of these super-cooled materials mentioned in the article - at the interface layer there'll be a net thrust equivalent to the inertia of the altered mass value.. and it's a unidirectional vector with no reciprocal.

Everyone looking at these new phenomenon must be aware of the implied FTL mechanism (it's also over unity, to boot) but i've been led to believe this is a misunderstanding due to the fact that when condensed matter physicists talk about electron mass, they really mean "effective mass" (which, incidentally, is distinct from relativistic mass, too).. and not inertial mass in the classical sense.

So yeah... i don't disbelieve this isn't the case... i just can't claim to fully understand it either... like others i've read, this article seems to casually imply OU FTL travel..
antialias_physorg
5 / 5 (1) Jun 14, 2012
a clarification is in order here; "effective mass" is a term used in condensed matter physics with a different meaning to conventional mass.

The way I google it effective mass is a term used to describe behavior of electrons different from what would be expected (e.g. in a magnetic field an electron - which has a specific charge - would be deflected a certain way).
In some circumstances (crystal lattices, low temperatures, high pressures, etc. ) that behavior differs from the expected. The electron deflects more or less (or amybe even in the entirley wrong direction). The change in behavior can be described by giving the electron another 'effective mass' (which can even be negative)

This has nothnig to do with the real mass of the electron (which is the thing that determines impulse/momentum). So this cannot be used for propulsion.
TkClick
1 / 5 (1) Jun 14, 2012
Perhaps i should explain further - the electron mass is constantly changing direction (as AC current)
It's the electron itself, what is changing direction, not its mass. Mass is scalar concept, not vector field. I presume, you're thinking about mechanism, in which EM-Drive or similar engines could work. IMO even if you could achieve the directional change of the effective mass of electron, this propulsion would remain constrained to the atom lattice, where the effective mass is changing, not into the vacuum outside of it.
MrVibrating
not rated yet Jun 14, 2012
@TkClick - Well if the electrons are changing direction then so are their masses, hence they're subject to inertia.

There's obviously no question AC current is possible, and if an asymmetrical inertial exchange occurred then it would apply as much to the macroscopic realm as it did to the microscopic; the only way around an N3 violation is for the researchers in this article to be talking about something other than conventional mass - because mass constancy is a prerequisite for CoE and CoM. The bottom line is that if we can vary the value of mass at will, we can have it go in one direction when heavier and the other when lighter - with each direction change leaving a non-zero inertia... which furthermore is a product of the force asymmetry rather than input energy, and which cares nothing for light constancy...

Which all seems horribly deviant... yet these are the inescapable consequences of being able to vary the value of mass.

Thus clearly these researchers mean something else..
MrVibrating
not rated yet Jun 14, 2012
@antialias - so which form of mass are we talking about here? I agree if it's effective mass then no violations are implied.

But if it's real mass.... like the article seems to be saying..?
MrVibrating
not rated yet Jun 14, 2012
@Howhot

"Forgive me if this is an ignorant question, but does this mean that a Cooper Pair is a quantum entangled electron pair?"

I believe any interaction between two or more quanta can entangle them - isolating them from interference while also being able to read / write to and from them is another matter of course.

IIRC, Cooper pairs occur when two similarly-polarised (so both up-spin or both down-spin) electrons become forced together against their mutual repulsion, forming an integer-spin boson from adding together the half-spins of the two fermions. This obviously puts the resulting particle on the other side of the Pauli exclusion principle - they become superposition-capable, like photons, gluons, W & Z etc., while losing the normal properties of baryonic matter.

Of course this isn't an exhaustive explanation.. but in short, yes, you're right.
MrVibrating
not rated yet Jun 14, 2012
Oops OK a closer look at the article (I should read more thoroughly before commenting, tsk!) reveals that the 'heavy' electrons are composites of two electrons - thus dissolving any suggestion of a symmetry break..

or does it...? The mass boost pertains to entanglements between bound vs free electrons - but nowhere does the article explicitly state their net mass - is it just double, per CoE, or x1,000 - as alluded to?
Howhot
not rated yet Jun 14, 2012
Thanks for the reply MrVib,

This is what I don't understand;
The degree of such entanglement appears to be the key to understanding what the heavy electrons do once they are formed and cool


The degree of entanglement? If it's a quantum entanglement, is there a "degree" of entanglement?

antialias_physorg
not rated yet Jun 15, 2012
@antialias - so which form of mass are we talking about here? I agree if it's effective mass then no violations are implied.


Here's a link to the page of Yazdani's lab
http://wwwphy.pri...bout.php

If you go to the publications section and click a few articles you'll notice that the summaries talk about effective masses (though the specific article mentioned above isn't linked...but that is only to be expected of a journal article since it isn't the property of the author but of the journal)

So my guess is that this article also deals with effective masses - not a real mass gain.
MrVibrating
not rated yet Jun 15, 2012
@Howhot - yes entanglement can be strong or weak, iirc depending on the number of Bell pairs the system can be described by.. there's also hyper-entanglement, where multiple properties of the same particles are entangled..

..i don't know what form of entanglement's proposed in this case though..
MrVibrating
5 / 5 (1) Jun 15, 2012
@antialias - so which form of mass are we talking about here? I agree if it's effective mass then no violations are implied.


Here's a link to the page of Yazdani's lab
http://wwwphy.pri...bout.php

If you go to the publications section and click a few articles you'll notice that the summaries talk about effective masses (though the specific article mentioned above isn't linked...but that is only to be expected of a journal article since it isn't the property of the author but of the journal)

So my guess is that this article also deals with effective masses - not a real mass gain.

lol well done for doing the leg work there, i guess it has to be 'effective mass' again then..

@PhyOrg writers - Please stop dropping the 'effective' prefix when these CMP papers talk about electron mass..? It's not trivial!!
baudrunner
not rated yet Jun 16, 2012
Deesky: "experts?" They are only mathematicians, and mathematics can prove the impossible. Walking-paper clutching "physicists" have to conform to the status quo, and when an authority of theirs posits theory, they have to conform to it. I have known well educated scientists who admit to having problems thinking. Einstein valued his imagination above his ability to acquire new knowledge. We honor his kind with the title of "expert".