(Fig.S) Electron spin is an unreal faster-than-light spinning.
Electron spin is unrealistic because a tiny (point-like) electron must be spinning much faster-than-light to generate the observed magnetic moment ( this lower ).
So quantum mechanics paradoxically started to claim this unphysical electron spin is Not actual spinning, though it allegedly has spin angular momentum.
This paradoxical nature of electron spin makes us realize we can explain all the experimental results based on this fictional electron spin by realistic electron's orbital motion.
Because both electron's orbital motion and fictitious spin are said to have the same indistinguishable magnetic field called Bohr magneton (= μB = only this magnetic field is measurable ) of Bohr's realistic orbit. ← Electron spin is unnecessary ( this p.2 ) with No experimental proof.
↑ Unphysical spin's angular momentum-1/2 or g-factor-2 can Not be directly measured (= spin-g-factor=2 has to be guessed from the measured Bohr magneton divided by unmeasurable spin-1/2 angular momentum allegedly caused by Not-real rotation, this p.4-2-obstacle ).
The unphysical quantum electrodynamics (= QED ) based on fictional virtual particles always gives meaningless infinities (+ artificial cancellation or hocus-pocus renormalization by other infinities ), which can Not predict spin-g-factor or anomalous magnetic moment at all, contrary to hypes.
↑ No evidence of electron spin-1/2.
In addition to the unphysical faster-than-light electron spinning ( this p.2-1.1 ), the electron spin unrealistically can Not be slowed down or accelerated no matter how many times electrons collide or interact with other particles ( this-1st-paragraph, this 3rd-paragraph, this 13th-paragraph ). ← Quantum mechanics provides No reason why the electron spinning speed is Not slowed down or changed.
On the other hand, the realistic electron's orbital motion can naturally explain the constant angular momentum or Bohr magneton based on the experimentally-verified de Broglie wave theory keeping the same angular momentum = an integer × ℏ ( this p.6 ) to avoid destructive interference of de Broglie wave.
As I said, the electron spin lacks reality, and its (measurable) magnetic moment can be replaced by the realistic electron's orbit, so the electron spin is unnecessary.
Atomic fine structure allegedly caused by the paradoxical spin-orbit magnetic energy can be naturally explained by the realistic Bohr-Sommerfeld fine structure without spin ( this 5th-paragraph, this-lower historical footnote ).
Anomalous Zeeman effect seen in alkali atoms such as sodium is too big to explain by the tiny spin-orbit magnetic interaction, so the electron spin disagrees with experimental results.
The energy difference between singlet (= spin up an down ? ) and triplet (= spin up-up, down-down ? ) states is as large as Coulomb electric energy (= 1 ~ 2 eV, this p.3-middle, this 3s3p singlet 1p and triplet 3p energy difference is 13140cm-1 = 1.629 eV ), which is far bigger than the tiny spin-orbit or spin-spin magnetic energy (= 0.0001 eV, this-p.10-left-2nd-paragraph ). ← electron spin cannot explain singlet-triplet large energy difference.
Pauli exclusion repulsive energy and ferromagnetism are also too strong to explain by the tiny spin-spin magnetic interaction (= electron spin magnetic energy is too weak, and useless ).
So quantum mechanics had to introduce the unphysical concept called exchange energy ( this p.17-19, this p.11-12 ) lacking exchange force ( this p.9-upper ) to explain these Pauli principle, ferromagnetism, singlet-triplet energy levels, whose energies are far bigger than the original spin-spin magnetic energy.
This unphysical exchange energy needs antisymmetric wavefunctions where all electrons in different orbitals and different atoms must be magically exchanged (= so each electron must unrealistically exist in all different atoms in this antisymmetric exchange wavefunction ).
All quantum mechanical Schrödinger equations for multi-electron atoms are unsolvable, so physicists have to artificially choose fake trial wavefunctions or basis sets with freely adjustable parameters as (fake) atomic unsolvable solutions, which cannot predict any physical values, and quantum mechanics is useless.
This Schrödinger equation is not only unsolvable, unable to predict any physical values, but also too time-consuming to calculate the energies of the chosen (fake) antisymmetric wavefunctions that must exchange all electrons' orbitals ( this p.2-3, p.5 ), and calculate all combinations of exchange energies.
So quantum mechanics has to rely on the ad-hoc rough approximation treating all different electrons as one-pseudo-electron or fictional quasiparticle model with fake (effective) mass in the current mainstream density functional theory (= DFT or Kohn-Sham theory, this p.3-5 ).
This one-pseudo-electron DFT must artificially choose (fake) exchange-correlation energy functional (= including the unphysical exchange energy ) and pseudo-potential, which cannot predict any values, so the unphysical exchange energy (= related to electron spin ) is an artificial concept irrelevant to quantum mechanical prediction (= DFT is Not ab-initio but just empirical, this 7~9th-paragraphs, this p.23 ).
↑ So the electron spin is also artificial, Not the result of quantum mechanical prediction (= No evidence of electron spin ).
In these antisymmetric wavefunctions and one-pseudo-electron DFT approximation, each electron must unrealistically exist in all different atoms and orbitals (= single electron is unrealistically shared by all atoms ) by the unphysical exchange interaction, which prevents each atom from having definite shape and boundary.
As a result, quantum mechanical unphysical exchange energy lacking exchange force hampers scientific development by preventing researchers from using real atomic models with experimentally-measurable shapes and boundaries.
This unphysical quantum mechanical exchange energy lacking exchange force is said to be caused by (fictitious) kinetic energy change ( this p.9-10 ) due to de Broglie wave (= Schrodinger wavefunction is also based on de Broglie wave theory ) interference in antisymmetric wavefunction.
↑ We should stop using these unrealistic quantum mechanical exchange energy (= linked to unrealistic electron spin ), quasiparticle, one-pseudo-electron DFT to develop useful nanotechnology based on real atomic model with actual shapes and real Pauli repulsive force based on real de Broglie wave.
(Fig.Q) If we start to use the experimentally-obtained real atomic model with actual shapes, quantum mechanical unphysical model is unnecessary, which is feared by academia, journals.
The important point is that (useless) quantum mechanics is unable to describe physical phenomena of materials and molecules by using real particles or concepts, which fatal defects of quantum mechanics cause the current deadend mainstream science.
All the media's misleadingly-colorful pictures are completely inconsistent with the present mainstream quantum mechanical unphysical shapeless atomic model.
Quantum mechanics has to rely on fictitious quasiparticle model or unrealistic quasi-electron with fake effective masses ( this p.2, this p.5-4th-paragraph ) to (meaninglessly) explain electromagnetic properties in metals, semiconductors, insulators, molecules and (misleadingly-overhyped) spintronics.
The paradoxical quantum mechanical Pauli principle requires every electron to unrealistically spread and exist in all different atoms inside materials by the unphysical exchange energy lacking real exchange force. ← This unphysical exchange energy is related to (unrealistic) electron spin.
This unreasonable Pauli exchange energy is why the current most-widely-used only mainstream quantum mechanical approximation called density functional theory (= DFT ) or Kohn-Sham theory tries to describe the whole materials as one pseudo-electron ( this p.2-3 ) or fictitious quasiparticle model with unrealistically-changeable effective masses and pseudo-spins using artificially-chosen pseudo-potentials or exchange functionals whose universally-exact form is still unknown ( this p.3-5, this p.6-7, this 3rd-paragraph ).
So quantum mechanical most popular DFT method (= the current only choice for solid or semiconductor physics ) just artificially choosing approximate exchange-energy functionals or pseudo-potentials often giving wrong results is an incorrect theory with No ability to predict any physical values ( this p.7. this p.4(or.3),p.13(or p.12) ) which means there is No such thing as a correct quantum mechanical prediction, contrary to the media-hype.
↑ Artificially-chosen pseudo-potentials or (fake) basis wavefunctions with freely-adjustable parameters show quantum mechanics is unable to predict any physical phenomena, meaning quantum mechanical methods are just "fake ab-initio" or ad-hoc empirical theory artificially fitted to experimental values ( this p.23-last-paragraph, this p.3-3rd-paragraph, this p.3-right, this p.4-2nd-paragraphs ), and it lacks real particle picture ( this-last-paragraph, this p.3-2.2 ).
↑ Quantum mechanical wavefunctions and its most widely-used DFT approximation are unable to give real atomic or electron picture with concrete shape or size, which unphysical quantum mechanical models hampers researchers from using real atomic model or shapes as practical parts for building useful nano-devices or treating diseases.
So it is far better to use the experimentally-observed atomic shapes and properties from the beginning than to waste too much time in the meaningless, useless, time-consuming unphysical quantum mechanical model and equations.
Actually, quantum mechanics often relies on unphysical band model (= using one fictitious quasi-electron approximation) that has to be based on wrongly-average pseudo-electron with fake effective mass and fictional crystal quasi-momentum (= or wavenumber k ), energy ( this p.3, this p.12-14 ). ← Band model can Not designate the precise positions of electrons due to unrealistically-spreading electron band model (= an actual individual electron must be bound to one atom at a time instead of the unrealistically-spreading band or electron's plain wave picture, this p.12-13 ), so useless.
Quantum mechanics can only express each electron and (fictitious) quasiparticle by using nonphysical math symbols such as creation and annihilation operators ( this p.3, this p.3, this p.2-Results, this p.2-Results ) and abstract (useless) 100-year-old equations called Heisenberg or Hubbard spin models where the fictitious (exchange) interaction parameter J, U or t must be artificially adjusted ( this p.5-6, this p.12, this p.4, this p.2-right ) with No realistic, consistent theoretical basis ( this p.3-last-paragraph ).
↑ The fact that the current mainstream atomic theory or quantum mechanics is unable to describe physical phenomena by real particles with real physical shapes and masses means scientists in all fields are unable to use real atomic or molecular models with real shapes and sizes as parts for designing and building useful molecular nano-machines for curing diseases.
This is why all the current applied science such as biology, medicine and manufacturing industry is deadend, as shown in still-incurable cancers, still-impractical hyped quantum computers, impractical green-new technology, already-dead Moore's law (= this is true, though many companies that want subsidy tend to refuse to admit it ) in semiconductor industry..
Due to the unphysical mainstream physics, researchers in all fields are wasting their time only in aiming to publish papers in journals instead of aiming to invent really useful machines or cure diseases.
These unphysical impractical concepts intended only for publishing papers in journals are the main reason why even old-fashioned archaic universities can skyrocket their tuition limitlessly by suppressing real scientific progress in all industries.
If researchers start to use the experimentally-observed actual atomic shapes and properties to develop useful technology, the current quantum mechanical unphysical impractical (quasiparticle) model and equations are unnecessary and forgotten.
↑ Academia and journals fear that researchers stop using the unphysical (useless) quantum mechanical model that just wastes their time, so they need to spread overhyped (pseudo-)science news almost everyday to suppress this inconvenient fact.
The 6th and 10th paragraphs of this science news about the alleged research offering insights into the metal-to-insulator transition say
"Quantitative determination of the interaction parameters in the Schrodinger's equation of real materials has been a very difficult task.. (= quantum mechanical Schrodinger equation has been useless for any multi-electron materials )"
"However, when the materials are quasi-one-dimensional (= Not real model ), the atomic lattice often violently fluctuates.."
↑ They ( this p.8-9, Fig.9, p.12-left ) tried to explain this mechanism using fictional quasiparticle models such as exciton and phonon, expressing those particles by nonphysical math operators with No realistic shapes and one-pseudo-electron DFT model with empirically-chosen exchange functional and many freely-adjustable parameters artificially fitted to experimental results. ← No quantum mechanical prediction, and useless pseudo-models lacking real particle figures or shapes hamper science development .
↑ This p.8-VII-electrons are expressed as nonphysical math operators (= c† ) with No shapes whose interaction parameters were artificially fitted to experiments, this-p.9, Fig.9-fictitious phonon, exciton quasiparticles' nonphysical math operators lack real shapes, this-p.12-left= one-pseudo-electron DFT with semiempirical correction, with No quantum mechanical prediction. ← useless quantum mechanical pseudo-model.
So the last paragraph of this hyped news just vaguely says
"Once we have their quantum DNAs in hand, these complex materials will (= just about speculative future, still useless now ) be a lot more tameable for predictive materials engineering (?)"
(Fig.E) Unrealistic electron (faster-than-light) spinning is unnecessary to explain any experiments which just detect electromagnetic field naturally explained by electron's orbital motion.
In fact, No experiments allegedly measuring electron spin can prove the existence of electron spin.
The electron spin is just an imaginary thing (= Physicists officially declare that an electron is Not actually spinning ).
Electron spin (magnetic) resonance (= ESR ) or electron paramagnetic resonance (= EPR ) is said to be the method of detecting electron spin (= though an electron is Not actually spinning ).
Of course, it is impossible to see the unrealistic electron spin (= if an electron is spinning, it must be the unrealistic faster-than-light spinning ! ) or its angular momentum (= or g-factor ) directly.
In ESR, all researchers can measure is energy level splitting (= through detecting light emitted from or absorbed into atoms ) under applied magnetic field B where the measured energy interval is equal to Bohr magneton (= μB ) × the magnetic field B × 2 (= difference between two orbits of upper and down magnetic directions ).
This ESR energy splitting can be naturally explained by the realistic electron's orbital motion whose magnetic moment is equal to Bohr magneton or the electron spin whose (spin) magnetic moment is also Bohr magneton ( this p.2, this 3rd-paragraph ).
Both the electron's orbit and electron spin are said to have the same Bohr magneton, accidentally, which are indistinguishable.
Because the magnetic moment is equal to g-factor × angular momentum.
Electron's orbital motion's magnetic moment = g-factor (= 1 ) × orbital angular momentum (= 1 ) × Bohr magneton = one Bohr magneton (= μB ).
Electron's spin magnetic moment is also spin-g-factor (= 2 ) × spin angular momentum (= 1/2 ) × Bohr magneton = one Bohr magneton (= μB, this p.3 ).
As a result, ESR can be naturally explained by the realistic electron's orbital motion, and the unrealistic electron spin is unnecessary (= the concept of Bohr magneton originally came from the successful Bohr's atomic orbit without spin ).
One of methods for allegedly detecting (fictional) electron's spin magnetic direction is magneto-optic Kerr effect (MOKE) where the polarization of the (classical) light wave reflected from (or penetrating ) the magnetic material changes depending on the material's magnetization, which material's magnetization has nothing to do with electron spin, though ( this p.13-1.1, this p.2-p.13 ).
Light or electromagnetic wave is known to change its polarization after being reflected by magnetic materials (= Not spin, this p.13(or p.7) ), depending on the direction of magnetic field (= magnetization or magnetic moment ). ← This magneto-optical Kerr effect (= MOKE ) or Faraday effect had been already known long before (unrealistic) quantum mechanics was born ( this p.20 ), so electron spin (or quantum photon particle ) is irrelevant to this light reflection.
In Faraday effect, the polarization of (classical) light wave getting through the material changes depending on the material's magnetization parallel or antiparallel to light propagation. ← the different directions of magnetization means the different directions of the electron's orbital motion that differently affects the right or left-circularly-polarized light.
These Kerr or Faraday effects can be naturally explained by classical electromagnetic wave theory and the realistic electron's orbital motion whose magnetic moment or Bohr magneton (= which modifies the light polarization ) is equal to that of (unreal) electron spin. ← Both the orbital motion and electron spin with the same Bohr magneton are indistinguishable with respect to magnetization.
Actually, in Kerr effect, only when the material's magnetic field includes the component parallel to the incident electromagnetic light wave's propagating direction (= polar or longitudinal ), this light's (magnetic) phase is modified, and resultantly the light's polarization is changed like linearly → elliptically-polarized light ( this p.3-5, this p.13-14(or p.7-8), this Figure 2 ).
↑ This Kerr effect just agrees with classical light wave theory = when the parallel component phase of electromagnetic wave changes, the light polarization (= linear ↔ circular ) is known to change.
Another main method of allegedly detecting electron's spin magnetic direction is inverse spin Hall effect (= ISHE ), which has nothing to do with electron spin, contrary to that name.
In the inverse spin Hall effect (= equal to spin Hall effect ), the magnetic current (= caused by electron orbital motion or unreal spin ) is said to be changed into the measurable electric voltage change ( this p.2-Fig.1 ). ← The unreal electron spin itself is directly undetectable in this method.
↑ Electrons orbiting in different directions are scattered or veer in the different directions (= left or right side ) due to the different friction or collision with the surrounding electrons like classical Magnus effect ( this p.3-2nd-last-paragraph ). ← A rotating ball veers into left or right direction, depending on the the ball's rotating (= electron's orbiting ) direction that influences the friction against the surrounding air.
↑ So when electrons' current with magnetization in one direction is injected, they tend to be slightly scattered in one direction (= left or right side with respect to the moving direction ), which causes the measurable (faint) electric voltage, which is the true mechanism of the inverse (fake) spin Hall effect or ISHE without spin.
↑ A point-like spinning electron (= Not actual spinning though ) with almost zero size can Not cause this (electric) scattering (= depending on the spinning direction ) due to the friction against the surrounding electrons (= electrons cannot directly touch each other due to Coulomb repulsion ), so it has to rely on paradoxical relativistic spin-orbit magnetic interaction that contradicts the original Einstein relativity, so the electron spin is false.
As one of ways to roughly estimate (fictional) electron spin's direction, the current physicists sometimes rely on very unreliable instruments called spin-ARPES (= angle resolved photoemission spectroscopy ) based on measuring the (electric) scattering direction of electrons ejected by (classical) light through photoelectric effect.
The point is it is impossible to measure the direction of the (unrealistic) electron spin itself or spin magnetic direction directly in this spin ARPES or other experiments.
Because if we apply external magnetic field to the unseen electron spin, this spin direction randomly flips (= changes ) in the direction parallel or anti-parallel to the external magnetic field, so the measured spin magnetic direction is not equal to the original unmeasurable spin direction.
In the famous Stern-Gerlach experiment, which just measured the magnetic moment of silver atoms instead of directly measuring the electron spin, the original silver's atom's magnetic moment direction was changed randomly in direction parallel or antiparallel to the external magnetic field.
So they have to rely on other methods (irrelevant to electron spin) of just measuing electrons' scattering direction like in spin-ARPES instead of directly measuring electron spin magnetic moment's direction ( this spin detector at Bloch, this p.9 ).
This p.6-2. says
"Unfortunately, the concept of a simple Stern–Gerlach type
spin separator does Not work for charged particles like electrons."
So they try to (baselessly) 'guess' the (imaginary) electron's spin direction by vaguely seeing the directions or intensities of electrons scattered by some metals like Au target, which method is called spin-ARPES.
In this Spin-ARPES, they (baselessly) claimed electrons ejected by incident light by photoelectric effect are sent to hit the metal, and get scattered by this metal toward right or left sides depending on the (unseen) electron's spin direction.
↑ So even this spin-ARPES cannot measure the direction of the electron spin itself or spin magnetic moment directly.
First of all, electrons easily change their original (fictitious) spin magnetic directions when they absorb the incident light's energy (= so they cannot know the material's original electron's spin state or direction by this spin-ARPES ), and they are also affected by the material's other electrons' magnetic fields.
And the directions in which electrons are scattered are very uncertain, unpredictable, and easily influenced by the irrelevant multiple Coulomb scattering with other electrons and nuclei (= of course, electrons' orbital directions instead of a point-like fictitious electron spin also infuence this scattering ).
↑ Electrons orbiting in different directions (= instead of the unrealistic spin ) are ejected and flying in slightly-different directions which easily affects the scattering directions or intensities of spin-ARPES result. ← Electron spin is unnecessary, electron's orbital motion can explain different scattering directions in spin-ARPES.
This p.2-2nd, 4th paragraphs-p.3 say
"we cannot simply use the spin of the electrons as a tag and measure
independently the photoelectron spectra for spin-up and spin-down electrons..
In practice, one therefore exploits the spin-dependence in
a scattering experiment (= instead of directly measuring spin's magnetic direction )
"
"Does the spin-polarized spectrum (= of spin-ARPES ) reflect the true spin polarization of the
electronic states in the system under study ? Unfortunately, this is Not necessarily true
several different mechanisms inherent in the photoemission process are discussed that affect the spin polarization that is experimentally observed"
"All these effects can hamper the characterization of spin-resolved bands in the ground state. They are in most cases not well known (= many unknown factors make spin-ARPES results unreliable )."
A spinning electron (= Not real spinning though ) is a point-like particle with almost no size, so it is impossible for such a point-like electron spin to affect electrons' scattering direction, when electrons hit the metal (= ex. Au target ).
So physicists needed to fabricate some imaginary mechanism of spin-ARPES where the electron spin direction affecting (Coulomb) scattering is said to be based on relativistic spin-orbit effect (= called Mott scattering ) or fictitious exchange interaction (= VLEED scattering, this p.49-52 ) lacking real exchange force ( this-lower-our approach ).
Though quantum mechanical artificial pseudo-model cannot predict this ad-hoc exchange energy or relativistic spin-orbit interaction due to artificially-chosen exchange-energy or pseudo-potential ( this p.10 ).
As shown in this, the relativistic spin-orbit effect is paradoxical and physically impossible, because they say moving electrons do Not experience (fictitious relativistic) magnetic field from the stationary nuclei, and only when seen from the electron's rest frame, the stationary nuclei appear to be moving and causing fictitious relativistic magnetic field that may affect spin-scattering direction through (fictitious) spin-orbit magnetic interaction.
↑ The fact that whether relativistic spin-orbit interaction may happen or not depends on observers' viewpoint (= seen from electron's rest frame or moving frame ) means this relativistic spin-orbit (fictitious) magnetic effect is paradoxical and wrong.
Furthermore, this spin-ARPES based on the fictitious spin-orbit effect (= Mott detector ) has very bad detection efficiency due to multiple uncertain scattering and accelerated electrons easily penetrating target metals without being detected ( this-middle-spin-resolved photoemission spectroscopy ).
This p.5-right-last-paragraph says
"However this effect is weak and cannot
be easily resolved at all scattering angles or energies..
At low energy the electron
cloud shields the nucleus reducing the Mott effect,
and for softer scattering angles the electron is likely
to multi-scatter (= this spin-ARPES cannot measure electron spin easily )"
Spin-ARPES based on (fictitious) quantum mechanical exchange energy (= called VLEED ) is said to distinguish the electron spin direction based on the ( unfounded ) assumption that electrons with different spin directions may be reflected by target magnetized metal with slightly-different probabilities ← the different electrons' scattering direction depends on electron spin direction through exchange interaction ?
But the detection efficiency of this spin-ARPES is also bad, and easily affected by many other irrelevant factors.
The detection efficiency of spin-ARPES is called Sherman function (= S ) which must be artificially and experimentally determined by fitting many free parameters, because different materials with different shapes and thickness, different incident lights, different angles easily change the measured electrons' scattering direction, and undermine the reliability of spin-ARPES or Sherman function ( this p.14-4. ).
The typical Sherman function or spin-ARPES detection efficiency is only about 0.2 ( this p.3-left ) which means spin-ARPES easily misinterprets the electron spin direction with 80% error rate.
This p.1-right says
"the estimation of Seff (= Sherman function ), however, is Not an easy task
The absolute calibration can be achieved by the usage of spin-polarized electrons,. but the setup of the spin-polarized electron source itself is hard work (= it is impossible to prepare electrons with some desired spin direction, because the applied magnetic field changes the electron spin direction randomly up or down ).
"
Even when this spin-ARPES was performed against the ferromagnets such as Fe, Co, Ni (= which should ideally show 100% spin polarization ), they often failed to show spin polarization ( this p.13-2nd-paragraph ).
Even in the latest research, the observed magnetic polarization asymmetry against ferromagnet nickel (= Ni ) is only less than 3.0% (= 97% electrons showed random scattering directions irrelevant to spin or magnetic directions, this-p.16-right-lower-green-line-asymmetry, this p.1-right obtained only 3.2% polarization asymmetry in magnetized ferromagnet Ni ).
This p.5-(2) showed Sherman function (= SFEL = non-error rate ) is only 0.1 (= 90% error rate ) and this p.6-Fig.2 says estimated polarization P is about 17% means the observed (fictitious spin) asymmetry is only 17% × 0.1 = 1.7% (= 98.3% of scattered electrons showed random scattering directions irrelevant to spin after absorbing incident light ).
↑ The directions of electrons' scattering are easily affected by positions, various conditions such as incident light and electron's orbital direction (= Not spin ), so this spin-ARPES based on uncertain electrons' scattering to roughly estimate (fictitious) electron's spin direction is very unreliable.
(Fig.M) Only a realistic electron's orbital motion instead of the unphysical spin can explain magnetoresistance, MRAM and spin-torque phenomena.
MRAM (= magnetic or magneto-resistive random-access memory ) is storing bit information 0 or 1 when magnetizations of two ferromagnetic materials are parallel (= 0 ) or antiparallel (= 1 ), as shown in this Fig.1.
When the magnetizations between two adjacent ferromagnetic materials are parallel or antiparallel, the electric resistance going through two ferromagnets becomes lower (= parallel = 0 ) or higher (= antiparallel = 1 ) due to magnetoresistance (= MR ).
↑ This MRAM's data reading mechanism based on measuring different electric resistance (= unphysical spin itself is unmeasurable ) due to magnetoresistance can be naturally explained by the electron's orbit instead of unrealistic spin.
"Writing" of MRAM is done by applying electromagnetic field ( this 7~8th-paragraphs ).
In MRAM, the electric current is said to flow through very thin layer between two ferromagnetic materials due to quantum tunneling with (unreal) negative kinetic energy. ← this is impossible. We have to replace this unphysical tunneling by realistic current with positive kinetic energy.
The present practical (classical) computer memories are using DRAM, SRAM, NAND.. which can efficiently store electric charges in capacitors by ordinary transistors without unphysical spin.
MRAM storing bit information as the form of direction of magnetization (= which they baselessly call electron spin, but it can be explained by orbital motion ) is inferior to the DRAM, SRAM without spin, because MRAM is slower, more energy-inefficient, error-prone than DRAM.
This-1. says "One of the biggest challenges with MRAM technology is making the write error rate (WER) as low as possible,"
The media, corporations and academia have baselessly insisted that MRAM based on spintronics (= actually electron is Not spinning ) is so promising that it would soon replace the current mainstream DRAM, SRAM without spin over the past two decades ( this 2nd~3rd-paragraph ).
This 2nd and last paragraphs say "MRAM in itself is not a new invention, with early products ranging back to 2006."
"While MRAM may never replace DRAM and SRAM" ← MRAM technology has stalled with No progress for the past two decades.
Even after the longtime researches and a large amount of money wasted, MRAM, which still cannot replace the DRAM, remains niche market as a fake promising memory with overhyped potential like the hyped graphene.
The 6th paragraphs of this site says
"While MRAM pioneers such as Everspin have seen some success in the embedded market for discrete applications and even demonstrated that MRAM can handle the extreme environments of automotive applications, it remains a niche memory."
The 2nd paragraph of this site says
"There are still plenty of skeptics when it comes to MRAM,.. That has limited MRAM to a niche role over the past couple decades, hampered by high costs, low density, and lower endurance"
This 2nd-paragraph says
"However, challenges facing the MRAM market include high manufacturing costs, limited scalability"
↑ All technologies including MRAM spintronics have stopped progressing, only hypes remain due to unphysical quantum mechanical model such as spin, quasiparticle ( this 3rd-last-paragraph ), and one-pseudo-electron DFT model ( this II used pseudo-potential ).
This overhyped news baselessly claims "Ultrafast laser-powered 'magnetic RAM' is on the horizon after new discovery"
↑ This original paper's abstract ( this-2nd-paragraph physical review research ) makes No mention of MRAM memory nor any practical application (= so useless research ), contrary to the hyped news.
↑ This (overhyped) research just transiently illuminated some material by light with No practical memory realized.
Spin-transfer torque (= STT ) MRAM tries to manipulate the direction of magnetic material's magnetization (= caused Not by the unphysical spin but by the electron's orbital motion ) by controlling the direction of electric current getting through the magnetic material, which still faces many challenges that makes STT-MRAM useless (= the overhyped media tends to hide this inconvenient fact, though ).
This 1~2nd paragraphs say
"Magnetoresistive random access memories (MRAMs)—a promising memory storage technology based on spintronics (= hackneyed cliche )—store bits of information in spin valves consisting of junctions of two magnetic layers. To write data in a MRAM junction, a magnetic field switches the magnetization of one of the two layers."
"..Recently, researchers started to explore a variation of the technique based on the spin-transfer torque (STT), an effect in which the layer magnetization isn’t switched by a magnetic field but by a spin-polarized current (= this spin-polarized means the current of electrons orbiting in some direction )
.. our present understanding of STT is still incomplete (= physical mechanism of spin torque is unclear )"
"In a spin valve, a current passing through a magnetic layer (usually called the “fixed” layer) becomes spin (= orbital motion ) polarized. After passing through a nonmagnetic layer, the current is directed into the second magnetic layer, or “free” layer. If the magnetizations of the two magnetic layers are not parallel, the spin-polarized current can be absorbed by the free layer. This absorption transfers some angular momentum, exerting a torque that can change the free layer’s magnetization, causing its direction to either oscillate or switch completely."
Spin-transfer torque MRAM can be naturally explained by the ordinary magnetoresistance (= MR ) and electron's orbital motion without spin.
When electrons orbiting in some direction (= not spin ) flow from the left to right side through the fixed (= thick pinned) magnetization layer, only electrons' orbits in the same direction as the fixed layer's magnetization (= caused by electron's orbits, not spin ) can pass through the fixed layer (= called spin filter, this p.8 ) due to magnetoresistance (= flow of electrons orbiting in the same direction or same magnetization feel less resistance ).
And electrons' orbits in the opposite direction to the fixed layer's magnetization (= orbits ) bounce back by large resistance (= due to crash of electrons' orbits in the opposite directions ), and cannot pass through the fixed layer, because of magnetoresistance.
As a result, these electrons' orbits in the same direction as the fixed layer's magnetization flow into the thin free layer in the right side and align the free layer's magnetization in the same direction as the fixed magnetization (= switching mechanism of STT-MRAM, this p.7, this p.14-2.2 ), as shown in this figure-middle.
When electrons' orbits (= not spin ) flow from the right (= free magnetization thin layer ) to left (= fixed magnetization thick layer ), all the electrons can pass through the thin free magnetization layer, and only electrons' orbits in the opposite direction to the fixed layer's magnetization bounce back to the free layer due to higher resistance between the opposite electrons' orbits in magnetoresistance, as shown in this figure-middle.
Other electrons' orbits in the same direction as the fixed layer's magnetization can pass through the fixed layer (= and disappear to the left ) with less resistance.
As a result, the free layer's electron orbital direction (= free layer's magnetization ) tends to be the opposite (= antiparallel ) to the fixed layer's orbit, when electrons flow from free (= right ) to fixed (= left ) layers ( this p.7 ).
So depending on the direction of electrons' current, the free layer's magnetization becomes the opposite from (= 1 ) or the same as (= 0 ) the fixed layer's magnetization, which is the switching mechanism of spin-transfer-torque-MRAM
A point-like electron spin with almost no size cannot explain this different scattering directions or magnetoresistance depending on the spin direction, which needs electron's orbital motion (= so quantum mechanics cannot explain magnetoresistance or STT-MRAM, and the unphysical spin model with freely-chosen parameters irrelevant to quantum mechanics tends to be used to explain this STT-MRAM, this p.8-9 ).
Despite the overhyped commercialization, STT-MRAM is still impractical with No more progress due to its slow speed, demand for high-energy or current, and endurance issues.
This p.1-right-1st-paragraph says " This renders STT-MRAM unsuitable for ultrafast applications such as cache memories. Moreover, the single path for both reading and writing makes it challenging to attain reliable reading operations."
STT-MRAM also has the reliability issues or high failure rate ( this p.5-right-2 challenge ).
This p.1-left-2nd-paragraph says
"Despite various advantageous features, STT-MRAM is
facing various reliability challenges including write failure,
decision failure, retention failure and failures due to read
disturb..
a write failure occurs when the bit-cell does Not flip
to its required value during the given write period. This can
happen, since the write process in STT-MRAM is of stochastic (= random, erroneous switch ) nature."
This 1st-paragraph says
"Magneto-Resistive Random Access Memory (MRAM) has so far generally failed to replace SRAM (= using electric current transistors instead of the unphysical spin ) because its Spin Transfer Torque (STT-MRAM) implementation is too slow and doesn't last long enough."
This p.1-introduction-1st-paragraph says
"STT-MRAM faces various challenges along with
its merits such as, the reliability of a tunnel barrier, long write latency and small energy efficiency due to still high
write current"
As shown in this paper (= p.3-Fig.2 ), the switch by this STT (= resistance dV/dI change by current I ) is random and unreliable.
As this paper p.3-right says, this spin-current-induced or STT switching needed magnetic field (= H ) in addition to electric field to align the thick fixed layer's magnetization, which is very inconvenient and impractical ( this p.1-right-last-paragraph ), compared to today's practical memory switching that needs only electric field (= DRAM, SRAM ).
The important point is that MRAM (= magnetoresistance ) and STT-MRAM are irrelevant to quantum mechanical prediction nor calculation.
Spin-current-induced torque behind this STT-MRAM is based on the abstract unphysical model called Lifshitz-Gilbert-Slonczewski equation allegedly explaining the spin flip by precession, but actually, this equation with freely-adjustable unphysical parameters lack real physical picture and mechanism.
↑ Researchers just artificially choose or manipulate freely-adjustable parameters of this (unphysical) spin-torque equations instead of explaining it from the quantum mechanical theory ( this p.3-(1).p.3-right, this p.2-lower~p.3, ).
This p.2-right-last says "We used equation (2) to fit the experimental results by choosing βST, βFT, resonance angular frequency ω0 and spectrum linewidth ∆ as fitting parameters" ← Just using fitting parameters, No quantum mechanical prediction, so No evidence that the spin-torque MRAM uses quantum mechanical spin.
This p.3-left-last-paragraph says
"Although qualitatively in accord with the Landau-Lifshitz model, the critical current data are not in quantitative agreement..
Assuming
a Co polarization of 38% and a damping coefficient α=0.007 determined from ferromagnetic resonance
studies of Co (= just using experimental values instead of quantum mechanical theory predicting it )"
This p.24-left-3~4th-paragraphs say
"Both show that the agreement between theory and
experiment is still incomplete."
This research paper ↓
p.3-right-last-paragraph mentions "photons and magnons", which are unreal quantum mechanical quasiparticle models" hampering clarifying true mechanism of MRAM
p.4-right-1st-paragraph says "Although we do Not have a complete microscopic understanding of these features (= spin-torque mechanism is unclear ) "
p.5-left-1st-paragraph used artificial fitting parameters: damping parameters α instead of quantum mechanical prediction, which means there is No evidence of spin.
p.5-left-2nd-paragraph says "the spin-switching effect may (= just speculation ) enable magnetic random-access memories in which the memory elements are controlled by local exchange-effect forces (= unphysical exchange interaction ) rather than by long-range magnetic fields"
This-summary-2nd-paragraph says
"However, the detailed mechanism of charge-to-spin conversion in ferromagnetic materials has Not been clarified. Thus, there was no valid guidelines to realize the high efficiency of charge-to-spin conversion (spin conversion efficiency) essential for application (= quantum mechanics failed to explain spin-transfer torque mechanism ). "
Spin-orbit-torque or SOT-MRAM (= still impractical ) tries to utilize the electric current parallel to the magnetic material surface as magnetization's switch.
↑ The electrons' orbits (= Not spin ) in one direction veer toward the magnetic material (= by spin Hall effect which can be explained by classical orbits' scattering in one direction or Magnus effect ). ← This material's magnetization (= orbit ) tends to become the same as the approaching electrons' orbits in one particular direction, as shown in this figure-lower.
This SOT-MRAM is also impractical because of many challenges such as its bulky size, erroneous switching, demand for high energy and additional instruments of generating external magnetic field and reading current.
↑ Despite the deadend spintronics, MRAM, STT-MRAM, SOT-MRAM, researchers have to continue to study about this hopeless unphysical spin theory only to publish paper in journals with No practical application.
SOT-MRAM is also too slow to be practical.
This p.1-right-last~p.2-left-upper says
"However, the development of
SOT-MRAM for ultrafast applications still remains challenging...
which is an obstacle for practical SOT-MRAM
applications...
Despite some progress, a clear field-free solution
for ultrafast SOT operations remains elusive for real applications"
This introduction-1st-paragraph says
"However, a challenge for SOT-MRAM is that each bit cell requires two access transistors, resulting in a larger unit area, limiting its application in high-density memory scenarios."
This-p.4-lower says
"Lowering the energy demand and enhancing the energy efficiency is an outstanding problem for the SOT-MRAM.
Today, though, the biggest problem with SOT-MRAM is that it only switches about 50% of the time (= too many errors to be practical )."
Quantum mechanics cannot predict this SOT-MRAM mechanism, either.
Researchers just artificially chose freely-adjustable parameters with No quantum mechanical calculation nor prediction ( this p.6, this p.5-right, ).
The latest research paper on spin-orbit-torque or SOT-MRAM ↓
p.1-rigt says ". This renders STT-MRAM unsuitable for ultrafast applications such as cache memories. Moreover, the single path for both reading and writing makes it challenging to attain reliable reading operations."
"However, the development of SOT-MRAM for ultrafast applications still remains challenging (= both STT and SOT-MRAM are still useless )"
p.2-Fig.1a shows even this latest SOT-MRAM switch is very bulky, as large as micrometer (= μm ), which is far bigger and bulkier than today's compact DRAM memory of only 20 nanometers.
p.3-Fig.2 shows switching probability (= PSW ) of this SOT-switch is bad and uncertain between 80 ~ 100% (= about 10% error rate ), which is too error-prone to be a practical switch.
p.5-right just artificially chose free parameters without quantum mechanical prediction nor calculation.
Actually, in this-p.3 6th-paragraph, reviewer #2 says
"On the other hand, the study focuses on micro-sized magnetic dots, and it is well-documented that
reversal mechanisms and energies are very different in µm compared to sub-100 nm dots.
Meanwhile, practical applications are clearly projected for sub-100 nm dimensions (= so this device of micro-meter size is too big to be practical )"
"..In Figure 2, the switching probabilities hardly converge to 100%, but they are not zero either. I raise some doubts about the switching reliability (= this latest SOT-MRAM switch is too erroneous )"
This research paper on SOT ↓
p.2-Fig.1c shows this SOT-switch is too bulky and big = about 10μm (= scale bar )
p.4-Fig.3-D shows this SOT-switch is too slow, one switch took about 3~5 seconds, and stochastic, unreliable ( this p.5-Fig.4-d ).
As a result, spin-orbit-torque or SOT-MRAM is too error-prone, too slow, too bulky to be practical, contrary to the media hype.
Quantum mechanics has to rely on unrealistic negative kinetic energy in tunnel current over extremely narrow space (= ~ nm ).
↑ In such a narrow space, their estimation of the potential barrier is wrong, and electrons can realistically flow over very short distance by thermal fluctuation or de Broglie wave interference pressure (= de Broglie wave has 'power' to push electrons and cause interference pattern ) even without the impossible negative kinetic energy (= so tunneling is Not the occult quantum mechanical phenomenon but realistic electron's current with positive kinetic energy by thermal fluctuation and de Broglie wave interference ).
(Fig.M) Small magnetic fluctuation (= electron's orbit, Not spin ) generated in magnetic material illuminated by light is misinterpreted as unreal magnon quasiparticle by quantum mechanics.
Quantum mechanics tries to explain small magnetic fluctuation generated in some materials illuminated with laser light by using imaginary spin wave or fictitious magnon quasiparticle in vain.
But electron spin, which needs faster-than-light spinning, is known to be unreal, so this magnetic fluctuation is caused by electron's orbit instead of the unrealistic electron spin.
Quantum mechanics can only show abstract nonphysical math symbols (= creation, annihilation operators a†, b†.. ) with No concrete shape or size as this fictional magnon (= spin wave ) quasiparticle ( this p.2-lower, this p.9-(55), this p.6-(26) ).
↑ This quantum mechanical bad habit of always describing physical phenomena by unphysical abstract symbols or models lacking real particle picture is clearly culprit of the current deadend mainstream science.
This tiny magnetic fluctuation or (unseen) spin wave (= or fictional magnon quasiparticle ) is too weak and too fragile to be useful ( this 3rd-paragraph ).
The lifetime of the fictional spin wave or magnon quasiparticle (= just tiny temporary magnetic fluctuation ) is said to be only nanoseconds ( this p.8-Figure 8, this p.4-Fig.3-(d), this 2~3rd-paragraphs ).
This research paper p.1-left says
"Magnons or spin waves are elementary quasiparticles, which
represent a collective motion of magnetic moments"
".. However, the utilisation of magnons in magnonic applications can be limited by their lifetime, which can range from a few tenths of a microsecond down to tens of femtoseconds."
↑ Even this latest research could Not extend the hopelessly-short lifetime of the (fictitious) spin wave, as this p.2-Reviewer #3's 2nd-paragraph says
"the evidence presented by the authors is Not convincing enough to prove
the undamped spin waves"
And the maximum distance over which the spin wave or magnon quasiparticle can propagate is only micrometer ( this p.3-Table I, this p.3-right-top ), which is too short-lived to use for data transmission or storage, contrary to hypes.
This p.1-right says
"Although this makes it practically challenging to control spin waves.. However, even the excitation of spin waves with applicational relevant length scales is challenging."
This p.1-abstract (= No mention of realizing practical application of magnon ) says "antiferromagnetic magnons can propagate over long distances, up to hundreds of micrometers" ← Magnon or spin wave just propagating only micrometers has No practical use.
↑ This fictitious magnetic magnon spin wave transiently excited by laser light cannot be amplified or sent over long distance, because spin wave cannot be increased or manipulated by ordinary electric field like the stable electric current, so the practical use of this (too weak) spin wave (= proragating only micrometer ) that cannot be manipulated nor amplified is impossible.
In fact, the current quantum mechanical (spin) theory can not predict nor explain this fictitious spin wave or magnon quasiparticle.
Physicists have to artificially choose various free parameters in the ad-hoc spin wave or magnon models without quantum mechanical prediction nor calculation ( this p.6-left uses modeling of magnon based on artificially- fitting parameters ).
This p.7-left-Micromagnetic simulation just chose and input several free parameters such as Gilbert damping and exchange constant A (of spin wave ) into open-source (classical) micromagnetic simulator called MuMax3 ( this p.27 ) without quantum mechanical calcilation (= No Schrodinger equation nor DFT was used ).
This p.7-right-micromagnetic simulations also artificially chose various free parameters such as exchange coefficient A, damping constant α with No quantum mechanical prediction nor calculation.
↑ No quantum mechanical prediction of (fictitious) spin wave means No evidence of spin wave nor electron spin.
Researches on this spin wave or fictional magnon quasiparticle are useless, full of only meaningless hypes.
(Fig.N) NV center just causes small energy splitting proportional to electron's orbit's magnetic moment called Bohr magneton (= μB ) × magnetic field (= sensor ? ), fictional electron spin is irrelevant.
Nitrogen vacancy (= NV ) center in diamond consisting of multiple electrons was often cited as a potential quantum magnetic sensor based on (imaginary) electron spin, but actually, this NV center is too fragile to be practical, and it does Not prove the existence of (fictitious) electron spin.
In NV center, physicists cannot directly measure the (fictional) electron spin.
Only its (spin) magnetic moment called Bohr magneton ( this p.2 ) can be measured, this magnetic moment is equal to and replaced by realistic electron's orbital motion.
So there is No evidence of electron spin, whose magnetic moment can be explained by electron's orbital motion in this NV center in diamond.
All physicists can measure in NV center is the light wave energy interacting with energy levels of NV center ( this p.4 ) whose energy levels' interval is the applied magnetic field B × an integer (= 2 due to 2 electrons involved ) × Bohr magneton (= μB, this p.1-right-lower, this p.2-left-[1] this Fig.1, this p.3-left-3rd-paragraph ).
This energy splitting related to Bohr magneton can be naturally explained by electron's orbital motion instead of unrealistic electron spin.
So this NV-center in diamond can Not prove the existence of (fictitious) electron spin (= quantum mechanics cannot explain its detailed mechanism even now, this p.3-2nd-paragraph, this p.5-left-last, p.5-right. p.11-left, this p.3-intro-1st-paragraph ). Ordinary electron's orbital motion can perfectly explain this.
Furthermore, this NV center is too fragile, and easily broken, degraded (= become inactive called decoherence, this p.2-2nd-paragraph, this p.1-left, this abstract, this-1.introduction-3rd-paragraph
).
And due to its susceptibility to a lot of irrelevant noise, precise detection of small magnetic field by NV center is impossible ( this p.1-right-top, this 2.3 ).
This p.2-upper says
"One of the current serious problems is noise, which reduces sensitivity of
NV center diamond sensors by broadening of the spectral linewidth and reduces
spectral resolution of the device"
This p.1-abstract says
"However, the promise of NV centers is hindered by a severe degradation of
critical sensor properties, namely charge stability and spin coherence, near surfaces ( 10 nm deep)." ← NV center is still useless due to its instability.
This p.3-1st-paragraphs say
"While this makes the NV center a powerful sensor, it
puts strict requirements for the surroundings. In fact, any noise or instability (and especially
nearby paramagnetic defects) can strongly degrade its excellent as-fabricated properties."
This p.2-2nd-paragraph says
"Despite the high magnetic sensitivity of NVs and their very small size, measuring nano-scale magnetic field
sources using NVs is still a challenge. Next to high magnetic sensitivity, proximity to the field source is essential
for such sensors. Therefore, a high quality shallow layer of NVs is desirable. When using conventional implantation or growth techniques, shallow NVs (< 5 nm from the surface) are mostly stable in the neutrally charged
state (= unusable as sensors, this 1.introduction-3rd-paragraph ). Even when a shallow NV maintains its charge, it usually has very short relaxation time leading to low
magnetic sensitivity"
This p.7-right-4th-paragraph and p.11-3rd-paragraph says
"For NV centres within a few tens of nanometres of the diamond surface,
surface-related charge instabilities and noise further degrade NV properties"
"Although there are promising opportunities, many challenges remain, probably calling for collaborations between multiple academic domains and industry"
See also This-p.2-I.introduction-left, This p.2-right, this p.18-8, this introduction-3rd-paragraph.
And it is impossible to produce NV centers in precise positions (= which affect their sensitivity to external magnetic fields ) inside diamond (= which means uncertain NV center sensitivities make it impossible to precisely measure the absolute value of the target magnetic field ), which fact makes the NV-center impractical as magnetometer.
↑ Because the sensitivity of NV center to magnetic field changes depending on the uncertain positions of NV centers or distance from diamond's surface ( this 1.introduction says distribution of NV centers at diamond is random, this abstract ).
This p.6-right-1st-paragraph says
"Since there is No precise control of the NV center density and their proximity to the surface, NDs (= nano-diamonds ) suffer from variability in their sensitivity. Factors such as local strain anisotropy and crystal impurities also lead to spin and optical properties variations. This inhomogeneity results in inconsistent measurements among different NDs."
This-middle Challenges and road ahead says
"Despite their remarkable potential, NV centers still face certain challenges: (= still useless )"
"Scalability: Building large-scale quantum computers using NV centers requires precise placement and control of individual centers, which presents a significant technical hurdle."
"Fabrication Challenges: Engineering diamonds with well-defined NV centers at specific locations remains a complex process."
The fact that NV center is still useless despite longtime researches shows the idea that this too unstable NV sensor may become quantum magnetic sensor is unrealistic, and just baseless hype.
The current unphysical quantum mechanical model trying to express multi-electron material as one-pseudo-electron DFT or quasiparticle with artificially-chosen pseudo-potential ( this p.8-1st-paragraph ) hampers the technological development in all fields including NV center.
Even this current mainstream (one-pseudo-electron) DFT (= density functional theory ) cannot explain NV center's energy levels or spin, as this p.4-2nd-paragraph says
"As mentioned above, DFT calculations of the excited states of the NV− center in diamond
have given contradictory results"
(Fig.Q) Spin qubit shows only complicated energy levels in each quantum dot irrelevant to electron spin.
Spin qubit quantum computer tries to use the spin up or down direction of an electron confined in a quantum dot (= called an artificial atom = a small semiconductor consisting of many atoms) by adjustable electromagnetic field as a quantum bit or qubit (= electron spin up = 0, spin down = 1 ).
↑ But an electron is Not actually spinning, so electron spin does Not exist.
Physicists can detect Not the electron spin itself but two energy levels whose interval is 2gμBB (= g is g-factor, μB is Bohr magneton, B is the applied external magnetic field ) interacting with microwave.
↑ If spin qubit really utilized the (fictional) electron spin, this g-factor must be "2".
But actually they can detect more complicated g-factor values completely different from electron spin's g-factor 2.
So there is No evidence of spin qubits using (fictional) electron spins.
The future practical quantum computer is said to require more than millions of qubits ( this 2nd-paragraph, this 3rd-paragraph, this 1st-paragraph, this p.3-1.introduction ).
But the current silicon spin qubits are only several ~ 6 qubits ( = each qubit can take only 0 or 1 values, so just 6 bitstring can Not compute anything. this p.1-left, Intel's latest hyped 12-qubit chip only for academic research with No practical use, is just about platform, and Not about building 12 qubits themselves ) which are far from practically-required millions of qubits.
In addition to these impractically small numbers of qubits, the current quantum computers (= still Not computers ) are too error-prone to be useful.
This p.5-Fig.5 shows preparing just 3-qubit GHZ state (= all 3 qubits are 000 or 111 bit states ) caused high error rate of 20~30% (= Fig.5g shows fidelity = 1 - error rate is 71.4 ~ 83.6% ), which is completely useless.
↑ To hide the inconvenient truth that the current quantum mechanical technology has been deadend and unrealistic, a lot of baseless media-hypes about the quantum computer-pseudo-science and fictional electron spin need to be created and spread every day.
The gyromagnetic ratio or g-factor is the ratio of magnetic moment to angular momentum. Classical electron's orbit's g-factor is 1, and the (fictional) electron spin's g-factor is said to be 2.
↑ This spin-g-factor itself is unmeasurable, and only the magnetic moment called Bohr magneton is measurable, which is the same as the classical electron's orbit, because the spin-angular momentum 1/2 (= 1/2ℏ ) is half of the orbital quantized angular momentum of 1 (= ℏ ).
Quantum dot-spin qubit uses the complicated (effective) magnetic moment or g-factor (= different from spin-g-factor 2 ) combining multiple electrons' orbital motion instead of the fictional spin, so the spin-qubit does Not use electron spin.
This p.2-right-4th-paragraph-ESR spectroscopy in quantum dot spin qubit used g-factor = 0.35, which is different from electron spin g-factor of 2.
This site ↓
p.59-6.1-Qubit uses g-factor = -0.44 (= Not spin g-factor of 2).
p.62-top says "effective (= fake ) g-factor geff, which can be larger than the bare (spin) g-factor."
This-p.3-Fig.2h used g-factor = 11.255.
This p.3-last used g factor = 9.28.
This p.1-right-lower used g-factor = -0.4.
↑ None of these g-factors is the electron spin g-factor = 2
So there is No evidence of electron spin in quantum dot can artificially control fake (= effective ) g-factor by applied voltage.
Silicon-type spin qubit is said to use the quantum dot's (unrealistic) electron spin up (= 0 ) or down (= 1 ) as each qubit's state.
But it is impossible to observe an unrealistic electron spinning directly.
And their so-called spin-qubit does Not use electron spin, because they used artificial g-factors different from the spin-g-factor of 2.
All they can measure is irrelevant electric current or Coulomb voltage ( this Fig.1c ) instead of electron's spin magnet.
They baselessly claim, when two adjacent quantum dots include two electrons with the same spin up-up or down-down, these two electrons may repel each other by quantum mechanical (fictitious) Pauli principle exchange energy lacking real exchange force, and eventually electric current may be blocked under applied voltage. ← just imagination
First of all, a quantum dot is an artificial (= Not real ) atom with about 50nm size ( this p.2-Fig.1 ) containing more than 1000 ~ 10000 of atoms that is far bigger than a single atom (= only 0.1 nm ), hence, each quantum dot has large space enough to contain more than two electrons without caring about whether two electrons enter one same smaller atomic orbital exerting Pauli exclusion principle or not.
Actually, in this quantum dot's Pauli blockade mechanism, one electron was artificially fixed by external electric field in the place completely distant from the other electron, and only this other electron could move as electric current through different routes ( this p.3-Fig.1 ), which had nothing to do with Pauli principle repulsion that requires two electrons to enter the same one tiny atomic orbital far smaller than a single quantum dot (= consisting of 10000 atoms ) or a bigger artificial atom.
In the actual quantum dot or artificial atom, much more complicated mechanism happens, and the electric current depends on relationship between electron's orbital motion and other surrounding atoms, which can be artificially-controlled by external (exchange) voltage ( this p.1-right-2nd-paragraph ). ← Fictional electron spin is completely irrelevant to spin qubit.
(Fig.F) A single electron 'breaks' into two fictional quasiparticles of spinon carrying only spin and holon carrying only charge !? ← this ridiculous impractical quasiparticle model stops science from advancing
Quantum mechanical Schrödinger equations for multi-electron atoms are unsolvable (= unable to predict atomic energies ), useless and too time-consuming for larger molecules and materials.
So quantum mechanics needs fictitious unreal quasipartice model with fake effective mass and charge ( this 3rd-paragraph ) to approximately explain the multi-particle material's electromagnetic properties such as electric conductance.
These unscientific quantum mechanical quasiparticle models lack real atomic shapes (= these old impractical quasiparticle models have made No progress for about 100 years ), so they clearly prevent the development of science and technology.
This 1st paragraph says
"where the collective behavior of a large number of interacting particles can be described as if they were single particles. These quasiparticles are Not elementary particles"
↑ So these fictional quasiparticle models with fake effective masses (= the current mainstream physical models ) just approximately (and incorrectly) represent the collective behavior of the actual many-atomic material as one pseudo-particles with No real shapes ( this p.2-left, this p.1-left ) due to the impractical multi-electron Schrödinger equations ( this 3rd-paragraph ).
This p.2-2nd~3rd paragraphs and p.4-3rd~4th-paragraphs say
"Very often, the Schrodinger equation
does not directly provide such an understanding (= quantum mechanical Schrödinger equation is useless )."
"As we cannot generally directly use the Schrodinger equation to understand an interacting system, we have to start from the beginning when we are faced with a many-body system. We have to treat the many-body system as a black box, just as we treat our mysterious and unknown universe (= quantum mechanics is unable to deal with many-atomic materials )."
"But, in the many-body system, the collective excitations are not elementary... Thus, in many-body systems we have collective excitations (also called quasiparticles ) "
"..If we believe that our vacuum can be viewed as a special many-body material, then we have to conclude that there are no elementary particles (= quasiparticles are Not real elementary particles )."
↑ To hide this inconvenient truth of the present deadend science based on unrealistic quantum mechanical quasiparticle models lacking physical shapes (= expressed just as meaningless math operators, this p.13-last-paragraph, this p.22 ), the media and academia need to spread overhyped news with misleadingly colorful particle picture (= fictitious quasiparticles can move faster than light !? this p.11-2nd-paragraph ) that appears to be real.
See this page.
See this page.
See this page.
See this page.
See this page.
See this page.
See this page.
(Fig.H) Spin Hall effect is Not by (paradoxical) relativistic spin-orbit interaction but by classical Magnus effect (= rotating ball or orbiting electrons feel friction from the surrounding, and veer into right or left depending on the orbital direction ).
In spin-Hall effect (= SHE ), a electron (= moved by electric field ) with the downward-angular momentum veers to the right, and an electron with the upward-angular momentum veers to the left.
This spin Hall effect usually observed only at very low temperature is too weak and useless, because the (spin-)polarized electron can move only several μm. ( this 6th-paragraph, this p.11-8.conclusions ).
There is No evidence of electron spin in spin-Hall effect where only the direction of the magnetization (= arrows in the upper figure ) can be vaguely measured by seeing how polarization of light reflected from the magnetization (= Not by spin but by electron's orbit ) changes in classical Kerr effect ( this p.2-right-last-paragraph ).
This spin Hall effect is said to be caused by the relativistic spin-orbit magnetic effect ( this p.10-11 ), which is paradoxical and impossible, though.
As shown in the upper figure, an electron (= e- ) moving under the external electric field feels only the electric field from the stationary nucleus (= Ze+ ) which does Not generate magnetic field ( this 4th-paragraph ).
↑ So in this frame of the moving electron (= rest frame of the nucleus = normal frame ), there is No magnetic field, No spin-orbit magnetic interaction, hence, No spin-Hall effect happens, which is clearly paradox.
The paradoxical relativistic theory has no absolute frame, so only in the rest frame of the electron (= abnormal frame ), the heavy nucleus (= Ze+ ) appears to be moving and causing fictitious relativistic magnetic field B ( this p.10, this p.3-Fig.3 ).
The electron with the upward spin has the downward magnetic moment, which is parallel to this fictitious relativistic magnetic field (= lower magnetic energy ) caused by the moving nucleus (= from the viewpoint of an electron, the stationary nucleus appears to be moving in the opposite direction ), so the electron veers to the right to lower this fictitious magnetic energy in the spin-Hall effect.
But as I said, this relativistic spin-magnetic interaction or spin-Hall effect happens only in the (unrealistic) rest frame of the electron (= heavier nucleus appears to be moving ! ), which is paradoxical and wrong.
The important point is that this spin-Hall effect contradicts the original Einstein relativistic theory, so wrong.
As shown in the upper figure, the spin-orbit coupling constant based on the original relativistic theory is very small = -3.7 × 10-6 ( this p.6 ).
↑ This spin-orbit coupling is the universal constant, so if the original relativistic theory is right, the spin-orbit coupling in all materials must be this value of -3.7 × 10-6.
But in actual materials, this spin-orbit coupling constants are completely different from the original relativistic theory (= even the signs of these constants are the opposite ! ), so spin-Hall effect and relativistic spin-orbit effect are contradictory and wrong.
For example, the semiconductor GaAs is said to have the spin-orbit coupling constant of as large as 5.3 in spin-Hall effect, which is 106 times larger than the original relativistic theory, and the opposite sign ( this p.9,p.24, this p.2-right-1st,4th-paragraphs ). ← The fact that these constants' signs are the opposite means the relativistic spin-orbit interaction is illusion.
This p.2-left-1st-paragraph says
"results from relativistic corrections in the Pauli equation and is known as Thomas
term, with λ = −ℏ2/4m2c2
≈ −3.7 × 10−6 Å2 (= original relativistic spin-orbit constant )..
for GaAs one finds λ = 5.3 Å2.
Thus,
the SO coupling in n-GaAs is by six orders of magnitude stronger than in vacuum (= original relativistic weak spin-orbit coupling ) and has the opposite sign"
↑ And the current (unphysical) condensed matter can only give fake effective mass (= m* ) of an (fictitious) electron or quasiparticle in spin-Hall effect ( this p.5, this p.14-3.11~p.15 ). ← Clarifying real mechanism behind spin Hall effect by fictional quantum mechanical model is impossible.
This wide discrepancy in the spin-orbit coupling constants clearly shows spin-Hall effect has nothing to do with relativistic spin-orbit interaction, contrary to the current mainstream explanation.
This spin Hall effect can be naturally explained by classical Magnus effect where the electron orbiting downward (or upward ) feels friction or collision from the surrounding electrons, and veers into right (or left, this p.3, this p.13-a, this p.3 ).
↑ The electron's orbital motion with the downward angular momentum means the left side of the electron's orbit moving forward experiences more friction and pressure from the surrounding electrons on the left side than the right side of the orbit moving backward, hence, this orbit tends to veer rightward.
↑ This spin Hall effect by the classical Magnus effect (= more powerful collision than the weak relativistic spin-orbit magnetic interaction, this p.3-lower ) perfectly agrees with experimental observation, and can remove the wide discrepancy between the current spin-Hall theory and the original weak relativistic spin-orbit effect with the opposite sign.
Physicists often artificially choose (fake) relativistic pseudo-potentials in the current most-widely-used one-pseudo-electron density functional theory (= DFT ) to explain spin-Hall effect ( this 2~3rd-paragraph, this p.8-upper, this p.2~3, this p.15-16, this p.6-left-last-paragaph-first-principle ) in the unrealistic way.
The free choice of these fake pseudo-potentials has nothing to do with the prediction of (unphysical) quantum mechanics or relativity (← Quantum mechanical Schrödinger equations for multi-electron atoms are unsolvable, unable to predict anything ).
Actually, quantum mechanics failed to give the clear mechanism of spin-Hall effect as this p.1-left says "the underlying mechanisms of
the SHE (= spin Hall effect ) remain somewhat mysterious and poorly understood.
.. The conventional
spin current is physically meaningless."
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