Ion-qubit quantum computers are useless forever, cannot be scaled up.

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Quantum computers are useless forever

(Fig.1)  Quantum computer companies (= IonQ, Quantinuum.. ) need to spread overhyped fake news to get investment money and hide their deadend impractical quantum computers.

Ion qubits using each unstable ion's two energy states as a qubit's 0 or 1 bit state is hopeless, impractical, can Not be scaled up.

Ion-qubit quantum computers using each ion's two energy states as one qubit's 0 or 1 bit values (= controlled by laser light ) are useless forever, contrary to hypes.

Ion qubits unstably trapped in electromagnetic field used in IonQ ( this-2nd-paragraph ) and Quantinuum can never to scaled up to more than 100 qubits, let alone to millions of qubits required for a (illusory) practical quantum computer ( this-4th-paragraph ).

This or this-summary says "IONQ's trapped Ion qubits technology is Not scalable enough for Quantum Supremacy."

IonQ's overhyped empty promise of 100-ion-qubits.

The 3rd-paragraph of this or this hyped news (7/9/2025) says
"Under an expected contract with KISTI, IonQ plans to (= still unrealized ) deliver an advanced 100-qubit quantum system (= one qubit takes only 0 or 1 value, so still Not a computer ) to enable research and industrial quantum computing capabilities (= hype ). The companies intend to develop a hybrid quantum-classical (= just classical computers )"

↑ This news contradicts other news saying ( this-2nd-paragraph,  2025 )
" The MoU (= memorandum ) integrates IonQ's cutting-edge 36-qubit (= Not 100 qubit ) systems into KISTI's high-performance computing (HPC) infrastructure"

↑ This IonQ's website's last says
"IonQ does Not give any assurance that it will achieve its expectations"

↑ So this IonQ's hyped 100-ion-qubits are just empty promise or classical computer's simulation, Not a real 100-ion-qubit quantum computer (= the overhyped IonQ cannot scale up from just 36 ion qubits ).

The 9th, 11th paragraphs of this hyped news (7/10/2025) say
"they could not only prepare two magic states (= some qubit state mixing 0 and 1 bit states with some probabilities ) from just eight physical qubits (= just 8 bitstring, still Not a computer ), but also perform a two-qubit non-Clifford gate with a logical error rate of about one mistake per 5,000 operations (= still impractically-high error rate )"

"Our simulations (= just simulation, still unrealized ) suggest we can use roughly 40 physical qubits (= still far from millions of qubits required for a practical quantum computer ) to create one very high-fidelity magic-state qubit (= still one reliable qubit 0 or 1 has Not been realized )"

Quantinuum's error-prone ion qubits unable to correct errors just discarded undesirable results illegitimately.

↑ This Quantinuum's paper ↓

p.4-Fig.5 says " the magic states are prepared using pre-selection... post-selection"

p.5-left-IV says "e Quantinuum H2-1 trapped-ion quantum processor.., and 56 qubits (= too small numbers of qubits, still Not a quantum computer ) total"

"the average acceptance rate across al single-copy experiments is 82.58% (= 20% results were discarded as errors )"
"The acceptance rate is 65.73% and 3 logical |−1⟩ state (= 35% results were discarded as errors )"

↑ So this Quantinuum research just discarded erroneous results by the illegitimate pre-selection (= repeat and reset until success qubits' results were obtained = very time-consuming ) and post-selection (= erroneous results were discarded without error correction ), so only 65 ~ 80% results were accepted ( this-p.6 ).

Ion qubits just less than 56 error-prone qubits with No ability to correct errors (= just discarding erroneous results post-selectively ) are impractical forever.

↑ So the actual error rates were 35 ~ 20 % in just less than 56 ion qubits, which is completely impractical.

This Quantinuum's paper's p.2-right-3rd-paragraph says
"Upon failure to verify the preparation a logical |0⟩ state, the qubits can be conditionally reset and the fault-tolerant preparation can be re-attempted in a repeat-until-success fashion or pre-selected upon verification (= primitive, time-consuming method without error correction )"

This Quantinuum's paper-p.1-right-last-paragraph says
" When an uncorrectable state is detected, our fault-tolerance procedure rejects the trial. This postselection"

↑ So contrary to the overhyped fault-tolerant quantum computer news, they just illegitimately discarded erroneous results (= pre- and post-selection ) without quantum error correction in just less than 56 ion qubits (= unable to be scaled up ).

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