Scott Aaronson Associate Professor, EECS
description
Transcript of Scott Aaronson Associate Professor, EECS
Scott AaronsonAssociate Professor, EECS
Quantum Computers and Beyond
Moore’s Law
Extrapolating: Robot uprising?
But even a killer robot would still be “merely” a Turing machine, operating on
principles laid down in the 1930s…
=
Is there any feasible way to solve these problems, consistent with
the laws of physics?
And it’s conjectured that thousands of interesting problems are inherently
intractable for Turing machines…
Relativity Computer
DONE
Zeno’s Computer
STEP 1
STEP 2
STEP 3STEP 4
STEP 5
Tim
e (s
econ
ds)
Time Travel Computer
R CTC R CR
C
0 0 0
Answer
“Causality-Respecting Register”
“Closed Timelike
Curve Register”
Polynomial Size Circuit
S. Aaronson and J. Watrous. Closed Timelike Curves Make Quantum and Classical Computing Equivalent, Proceedings of the Royal Society A 465:631-647, 2009. arXiv:0808.2669.
What we’ve learned from quantum computers so far:
15 = 3 × 5(with high probability)
Linear-Optical Quantum Computingwww.scottaaronson.com/papers/optics.pdf
My student Alex Arkhipov and I recently proposed an experiment, which involves generating n identical photons, passing them through a network of beamsplitters, then measuring where they end up
Our proposal almost certainly wouldn’t yield a universal quantum computer—and indeed, it seems a lot easier to implement
Nevertheless, we give complexity-theoretic evidence that our experiment would solve some sampling problem that’s classically intractable
Groups in Brisbane, Australia and Imperial College London are currently working to implement our experiment
Summary1. From a theoretical standpoint, modern
computers are “all the same slop”: polynomial-time Turing machines
2. We can imagine computers that vastly exceed those (by using closed timelike curves, etc.)
3. But going even a tiny bit beyond polynomial-time Turing machines (say, with linear-optical quantum computers) is a great experimental challenge