Professor of Quantum-Mechanical Engineering

Dear Mr. President,

Thank you for your invitation to advise you on matters of science. Science is after all the most public form of knowledge.

Scientific knowledge consists exactly of those pieces of information that can in principle be verified by anyone with the tools and desire to do so.

My advice to our highest elected official is to keep science public. Secret knowledge, no matter how laboriously acquired, is less than science.

Some knowledge, of course, must remain secret for the security of the nation. Do not have the National Security Administration publish its cryptographic keys.

But unless there is a clear security risk, publish all else. Why? Science belongs to the public: they pay for it; they benefit from it. The benefits of scientific knowledge accrue far more rapidly when that knowledge lies open for all to see, to test, and to try.

Your administration has presided over some good examples of the benefits of open dissemination of scientific knowledge. I will restrict my attention to my own field of quantum computation.

Quantum computers are devices that store information at the level of atoms, and that process that information in a way that respects the wave like nature of quantum mechanics. Quantum mechanics is famously weird, and one of the consequences of quantum weirdness is that even a small quantum computer, consisting of a few thousand atoms, would be able to break all existing public-key cryptosystems.

By their potential power, quantum computers pose a significant threat to the security not only of classified encoded material, but to the security of most commercial transactions, in particular those that take place electronically. Despite the clear application of quantum computation to problems of national security, your security agencies have elected to pursue the majority of their research on quantum computers by open competition for public funds, under the stipulation that the results of the research be published and made available to all.

This is a wise course. Although potentially highly disruptive, quantum computers are hard to build. Large-scale quantum computation is a decade away, at least. To construct such large-scale quantum computers will require the scientific and engineering community to solve wide-ranging problems of nanofabrication and control. The solutions to such problems will have wide application in the design and manufacture of high precision, high-power technologies across the board. The potential benefits of such research are a thousand times greater than any drawback from potential disruption to security.

By keeping the science public, your agencies are dramatically speeding the development not only of quantum computers, but of a wide variety of other quantum technologies, ranging from enhanced lithography to more accurate atomic clocks, to precise global positioning. The frontier of the very small offers huge space for development: keep this frontier open to all.

Science is public knowledge. But science is not the only field where openness is important. The security failures of 9/11 were caused not by too little, but by too much secrecy. And the discussions that form public policy should be public.

I know that other advisors are offering you conflicting advice: keep your cards close to your chest—don't let our enemies (or our allies) benefit from our hard-earned knowledge. Don't listen to them. Science isn't poker: it only works when the cards are dealt face up. Don't go down in history as the Texan who closed the scientific frontier.


Seth Lloyd
Professor of Quantum-Mechanical Engineering
Massachusetts Institute of Technology