The discovery of quantum mechanics in the early 20th century spawned a revolution that tore through scientific disciplines with abandon. It helped to explain, among many other things, the structure of the atom; the periodic nature of the elements in chemistry; and why some solids conduct electricity while others do not. Armed with this foundational knowledge, scientists and engineers developed transistors, which were assembled into integrated circuits, which became the central architectural elements of sophisticated processors of information.
Computers initially filling up entire buildings and cost many millions of dollars; now they fit comfortably fit into the pocket of a teenager. Our understanding of light and subsequent invention of the laser led to fiber optic networks, satellite communication and the physical underpinnings of the global internet. Physicists do not use the term “revolution” lightly.
Now, scientists and engineers are excited about a “second quantum revolution,” one whose impact could potentially eclipse the first. An outgrowth of our quest to understand and control quantum behavior has given rise to remarkable developments—the idea of a “quantum computer,” and a “quantum internet.” Quantum computers can solve certain types of problems exponentially faster than ordinary computers. If a sufficiently powerful quantum computer can be built, it could factor numbers (e.g., 15 = 3 x 5) faster than any known supercomputer. This “quantum party trick” could completely undermine the encryption schemes currently used to send information securely over the internet. And if a quantum internet can be built, it could completely replace