For most of the field's history, quantum-computing research has been backed by governments or big information-technology firms.
Increasingly, though, the venture-capital (vc) industry is showing an interest.
PitchBook, a research firm based in Seattle,
has tracked $495m of vc money that has been invested in quantum computing so far this year—
almost double last year's total.
Dozens of startups are competing with the incumbent tech giants.
And established companies, such as Daimler, a carmaker, and Goldman Sachs, a bank,
are beginning to experiment with the nascent industry's products,
hoping that, if they can master them, they will bestow an advantage over their competitors.
Much of the money is going towards building hardware.
Doug Finke, a physicist who runs the Quantum Computing Report, which focuses on the nascent industry,
is aware of 87 organisations, big and small, trying to construct quantum computers.
Unlike classical computing, which had settled by the 1970s on silicon transistors as the units of computation,
there is, as yet, no consensus on the best way to build a quantum computer.
IonQ, a firm in Maryland that has raised $84m,
uses trapped ytterbium ions, manipulated by lasers, to perform its calculations.
Rigetti Computing, a Californian company which announced earlier this month
that it would be building a quantum computer for the British government,
employs microwaves to control pairs of electrons flowing through superconducting circuits.
Microsoft, although very much not a startup,
is working on a "topological" quantum computer that relies on the interactions of super-cold electrons.
One particularly well-financed new firm is PsiQuantum,
which does its computing with photons that run along waveguides etched onto ordinary silicon chips.
It hopes to leapfrog the NISQ era entirely and produce a fully fledged quantum computer within about five years—
though that is far sooner than most experts think feasible.
PsiQuantum was founded in 2015 by researchers from Imperial College and the University of Bristol, both in Britain.
It has raised $215m from backers including Black-Rock, a giant investment firm,
and the Founders Fund, an American vc company that was an early investor in SpaceX and Facebook.