SAN FRANCISCO — Microsoft is putting its considerable financial and engineering muscle into the experimental field of quantum computing as it works to build a machine that could tackle problems beyond the reach of today’s digital computers.

There is a growing optimism in the tech world that quantum computers, superpowerful devices that were once the stuff of science fiction, are possible — and may even be practical. If these machines work, they will have an impact on work in areas such as drug design and artificial intelligence, as well as offer a better understanding of the foundations of modern physics.

Microsoft’s decision to move from pure research to an expensive effort to build a working prototype underscores a global competition among technology companies, including Google and IBM, which are also making significant investments in search of breakthroughs.

In the exotic world of quantum physics, Microsoft has set itself apart from its competitors by choosing a different path. The company’s approach is based on “braiding” particles known as anyons — which physicists describe as existing in just two dimensions — to form the building blocks of a supercomputer that would exploit the unusual physical properties of subatomic particles.