QuanTube Research Note

Coherence Time Is the Whole Ballgame

From the QuanTube Blog · Fault-Tolerant Quantum Computing

A classical bit, once set, stays set. A qubit is the opposite: the instant you create a delicate quantum state, the environment begins to destroy it. Stray heat, magnetic noise, and material defects all conspire to collapse it.

The window in which a qubit retains its quantum information is its coherence time, and every algorithm runs inside that window. Too short, and the computation decoheres before it finishes, leaving noise where the answer should be.

This is why so much of QuanTube's engineering is unglamorous materials and fabrication work: better substrates, cleaner interfaces, tighter shielding. Each marginal improvement in coherence buys more usable computation.

Flashy qubit counts make headlines, but coherence is what makes those qubits useful. A thousand qubits that decohere instantly compute nothing. The quiet work of extending coherence is where real capability comes from.