It takes a lot of energy to synthesize fertilizer because the catalysts for
converting nitrogen gas into ammonia only work at high temperatures
and pressure. For some bacteria, making ammonia with the enzyme
nitrogenase is no sweat. Chemists want to learn the details of how ni-
trogenase works in order to mimic it with a synthetic catalyst that can
be used to make less energy-intensive fertilizers.
But the active site of nitrogenase, the part that interacts with nitrogen
and enables the reactions, can’t be modelled on classical computers.
Other important biological enzymes, such as the one that performs the
first step in photosynthesis, present a similar problem. This spring, re-
searchers at Microsoft estimated it would take hundreds of thousands
to a million qubits to simulate nitrogenase’s active site.
Improving clean-energy catalysts
The active site of nitrogenase can’t be modelled on classical compu-
ters because it’s made up of transition metals. Transition metals such
as iron, cobalt, and platinum have many electrons. For this group of
atoms in particular, chemists can’t find the right answers if they dis-
miss quantum mechanics in their simulations.
Many catalysts are transition metals. This includes those found in en-
gines and fuel cells, and catalysts used to make chemicals and fuels.
Simulating their behavior on quantum computers could help chemists
make them work faster at lower temperatures, or substitute less expen-
sive metals for catalysts like platinum.
Investigating distant galaxies
To figure out the composition of faraway galaxies, astronomers take
their clues from the wavelengths of light t hose galaxies emit. Small
quantum computers may enable researchers to more accurately deter-
mine what colors of light different types of molecules give off, a pro-
perty called their molecular spectra. Armed with this updated infor-
mation, astronomers could learn more about faraway celestial objects.
Fabricating high-temperature superconductors
Superconductors are highly conductive materials—but they only beha-
ve this way at very low temperatures. Like transition metals, supercon-
ductors are difficult to accurately model because of the quantum me-
chanical behavior of their electrons. Today superconductors are used
to make qubits, as well as strong magnets for medical imaging systems
and particle accelerators. By modeling them on quantum computers,
researchers hope to figure out how to make superconductors that work
at higher temperatures.
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