Many-body quantum systems are the most powerful computers allowed by Nature.

How do they work? Can we control them? Are they useful?

In this talk, I discuss how recent results in quantum information theory translate into quantum engineering solutions. I introduce a geometric information measure that rigorously evaluates the difference between two complex configurations of arbitrarily large quantum systems, e.g., thousands of interacting atoms. The result is instrumental in finding the maximum conversion rate of physical resources, such as energy and time, into quantum computational power. A simple but universally valid inequality, formally similar to the Heisenberg uncertainty relations, bounds the size of a program that creates a target quantum state by its experimental cost.

Finally, I outline strategies to tackle critical problems related to information storage in quantum networks, diagnostics of quantum devices, and quantum sensing. New ways to identify, quantify, and harness distinctive traits of quantum particles, e.g., entanglement, will accelerate the transition of quantum technologies from textbooks to reality