Quantum Hanky-Panky: A Conversation With Seth Lloyd

it has become clear over the last decade that photosynthesis—where a particle of light comes in from the sun, is absorbed by a chlorophyll molecule, the energy rattles around inside a leaf and gets turned into more leaves—is operating in a very quantum mechanical fashion.

Exactly the same kinds of models that we use to look at quantum computation allow us to understand what’s happening in photosynthesis. It turns out that photosynthetic plants, bacteria, and algae are extremely sophisticated in the way they use quantum mechanics. They use quantum coherence and funky effects like entanglement to get very high efficiency of energy transport.

.. Indeed, what’s happening in quantum information and quantum computing is it’s become more and more clear that quantum information is a universal language for how nature behaves.

.. this centerfold showed which parts of physics were talking with other parts of physics, who in this field was talking with this other field. They had to put quantum information right in the middle because everybody was talking with the people in quantum information.

.. by using ideas from quantum information, we’ve constructed systems that are much better than even the most efficient, naturally occurring system.

.. Twenty years ago, I wrote the first algorithms for how you could program the quantum computers we have now to explore how their quantum systems behave.

.. If you want to find out what happens when you send a photon a few billionths of second backwards in time and have a try to kill its former self, well, we have experiment that tests to see what happens when you do that.

.. It also turns out that quantum computers can detect and identify patterns that are very hard for a classical computer to detect. For example, if you have a huge dataset like the tick-by-tick history of all the stocks in the Dow Jones over the last fifty years, it’s a big dataset.

If you say, “I’d like to process this to find out what a good portfolio would be for me if I can tolerate a certain amount of risk and I want to have a certain amount of return.” Well, with a pretty small quantum computer, the kind that we’re going to have in the next five years or so, you could find the answer to that question much more accurately then you could do on a classical computer.

.. I, myself, am a theorist, so the experimentalists don’t like me to use a screwdriver in their lab because I tend to break things

.. Quantum computers are still at the stage where we have a small number of bits—10 bits that we can use, soon 50 bits, 100 quantum bits that we can use. Even though this is piddling by comparison with the classical computer, because quantum computers for specific problems are so much more powerful than classic computers

.. Lockheed Martin has bought a D‑Wave computer, Google and NASA have bought them, the Army is buying some of them.

.. I’ve been working with the folks at D-Wave to try to figure out why they are successful when they shouldn’t be. Ever since then, I patent everything by the way, even if I don’t know whether it’s going to work or not.

.. The strategy I’ve learned is that there’re a huge number of technologies out there, and we don’t have to adopt them. You don’t have to adopt these technologies.

You can use the ones that you like. You can not use the ones that you don’t like. I don’t use Facebook or Twitter or other social media, because I feel that there’s presence and there’s absence, and then there’s cyberpresence, and cyberpresence is a heck of a lot closer to absence than it is to actual presence.

.. DARPA was the first funding agency to recognize that this role of quantum mechanics in photosynthesis was a very important thing. They created the first program to fund looking at funky effects like quantum coherence and entanglement in photosynthesis and in energy transport.

.. The largest group or concentration of people working on quantum computation are in Canada at the Institute for Quantum Computing, in Waterloo

.. He had this intuition, and he came up with a formal notion of a quantum computer. But for more than five years or so, he couldn’t come up with something where it could do better.

Then when he finally came up with something, he showed where a classical computer takes two or three steps on average to this problem, a quantum computer can do it in one.