Home page
Quantum computer is useless
Quantum computer cannot calculate molecules
(Fig.1) Quantum mechanics is impractical, whether classical or (useless) quantum computers are used.
Is is wrongly said that only quantum computers could design greener, low-energy fertilizers or tackle food shortage by clarifying the nitrogenase enzyme's iron-molybdenum active site (= FeMo-co ) converting nitrogen gas into ammonia.
This or this-11th-paragraph says -- Fake quantum fertilizer
"With quantum computers, we could actually make fertilizer, just as one example, in an entirely different way, use way less energy, save the planet, and actually help farmers"
Quantum mechanics cannot solve its Schrodinger equation nor predict any multi-electron atomic energies, much less design fertilizers, contrary to hypes.
Physicists have to artificially choose fake trial wavefunctions (= basis sets ) with infinite terms and infinite free parameters out of infinite free choices to find ones giving the lowest energy in the impractical quantum mechanical approximate variational methods that take infinite time and cannot predict anything ( this or this-p.4-1st-paragraph ).
Overhyped quantum computers are impractical forever, too error-prone to calculate anything, cannot factor even 21, much less simulate the nitrogenase for better fertilizers.
This or this-Current quantum models in agriculture: status and barriers-4th-paragraph (2025) says
"Significant barriers impede widespread adoption of quantum models in agriculture. The foremost challenge is the current limitation of quantum hardware, with most quantum computers operating with relatively few qubits and high error rates, making them unsuitable for the complex calculations required in agricultural applications"
For the impossible dream of making better fertilizers, they rely on deceptive hybrid methods called variational quantum eigensolver (= VQE = classical computers must calculate energy by optimizing free parameters instead of useless quantum computers ) based on the impractical quantum variational methods that cannot predict anything nor fertilizers ( this-p.1~p.2 ).
↑ The results of this impractical quantum variational method or variational quantum eigensolver (= VQE ) are changed depending on the artificially-chosen fake trial wavefunctions (= ansatz ), which cannot predict any atomic energy ( this-p.1-abstract ).
↑ Furthermore, this impractical quantum mechanical variational method or VQE is too time-consuming to calculate actual molecular energy ( this or this-11~12th-paragraphs, this-p.1-right-2nd-paragraph ).
↑ This overhyped news (= middle ~ lower ) on quantum computer fertilizer used only useless IBM's 6 qubits (= one qubit takes only 0 or 1 value, so still Not a quantum computer ) in the impractical variational quantum eigensolver (= cannot predict anything ) on very simple molecules (= far from fertilizers, this-p.2 )
The recent research wrongly claimed some quantum mechanical methods run on classical computers could explain the energy of fertilizer's nitrogenase.
↑ Due to the unsolvable Schrodinger equation, quantum mechanics cannot predict any molecular energy such as nitrogenase, whether classical or (impractical) quantum computers are used, contrary to the overhyped fake news.
This or this-classical computer's nitrogenase news (2026) ↓
2nd-paragraph says -- Impractical quantum computer
" Chan, however, has long doubted that powerful quantum computers — which are still years away — will be necessary."
17th-paragraph says
"Part of what makes nitrogenase so chemically difficult is its active site — a cluster of iron and molybdenum atoms called FeMo-co"
29th-paragraph says -- Useless Schrodinger equation
"In principle, the Schrödinger equation tells you how all these different configurations contribute to the ground state and what its overall energy should be. But in practice, solving that equation directly and exactly for a system with as many interacting electrons as FeMo-co has is often impossible."
30th-paragraph says -- Guess wrong energy
"This is true for both quantum and classical computers. In both cases, you have to start with a simpler approximation of the ground state’s basic structure — an educated guess, often reached only after years of research, about which configurations are contributing the most to the ground state."
33th-paragraph says -- No quantum computer advantage
"quantum computers still encounter the same bottleneck of needing that reasonable initial guess, and there’s no obvious reason why quantum methods should have any advantage at clearing that bottleneck"
36th-paragraph says -- Ignore most electrons.
"they started with their guess and incrementally adjusted the behavior of small numbers of electrons. They then showed that adjusting larger numbers of electrons didn’t lead to significant energy changes"
4th-last-paragraph says -- Still useless
"But getting from the ground state to a full mathematical description of the reaction will be far more difficult, involving calculating energies for a whole sequence of intermediate chemical states. We're not even close to achieving the holy grail of this"
↑ So it is impossible to improve fertilizers or clarify nitrogenase in the current useless quantum mechanics unable to predict anything, whether classical or (impractical) quantum computers are used ( this or this-last ).
↑ This-paper on classical computer's nitrogenase ↓
p.2-last-paragraph~p.4 says -- True total energy is unknown
"The first uses the
113 electron, 76 orbital active space (= only part of all related electron orbitals were chosen as active space, which cannot predict true total energy, this-p.4-2nd-paragraph )
Although this total energy (= of only the chosen electrons ) is not physically measurable
p.5-2nd-last-paragraph says -- Impractical quantum mechanics
"The main methods we use here are the DMRG (= density matrix renormalization group = approximate version of Full-CI, this-p.1-right-last~p.2 ) and coupled cluster (CC)
theory."
"DMRG is a variational method (= cannot predict anything ) controlled by a parameter (bond dimension) D, and the calculation can be made arbitrarily accurate by increasing D (= impractical DMRG, this or this-p.11-6 )." ← DRMG relying on infinite (= arbitrary ) numbers of parameters D and chosen trial wavefunctions (= basis sets ) cannot predict anything ( this-p.4,p.8 this or this-p.4,p.9,p.19 )
"CC theory provides a non-variational estimate" ← The non-variational CC or CCSD is a wrong quantum mechanical approximate method giving wrong energy lower than true atomic lowest energy ( this or this-6.30 ).
↑ As a result, this overhyped research just artificially chose fake trial wavefunctions for unsolvable Schrodinger equations in the quantum mechanical approximate CC (= non-variational, wrong approximation ) and DMRG (= variational method unable to predict anything with infinite arbitrary free parameters ) only in some electrons and orbitals in active space, which cannot predict any molecular energy, whether classical or (impractical) quantum computers are used.
Only multi-probe atomic force microscopes and a realistic simple atomic model with shape discarding the impractical quantum mechanics can directly clarify enzymatic reactions and make better fertilizers ( this-figure-middle~lower ).
Feel free to link to this site.
