Optimizing the Layout and Error Properties of Quantum Circuits

Friday, October 21, 2011 - 10:47am


Wednesday, November 2, 2011
3:30 – 4:30 PM
Room 1132 Harold Frank Hall

HOST: Fred Chong

SPEAKER: John Kubiatowicz
Professor, Electrical Engineering and Computer Sciences
UC Berkeley

Title: Optimizing the layout and error properties of quantum circuits


In this talk, I will discuss Berkeley’s efforts at designing efficient
architectures for Ion-trap quantum computers and will present our
Computer Aided Design (CAD) flow for quantum circuits. The CAD flow can
automatically insert quantum error correction, partition and layout
quantum circuits, optimize the placement of teleportation and error
correction operations, and evaluate the error properties of the
resulting layout. With the CAD tool, we are able to study and optimize
large quantum circuits (such as adders, Shor’s factoring, etc). Among
other things, I will argue that quantum circuits should be evaluated in
the context of suitable metrics such as ADCR — the probabilistic
equivalent of the Area-Delay product. This talk will reinforce some of
the important recent lessons in quantum computing, such as the fact that
communication cost and errors significantly impact the behavior of
quantum circuits — so much so that a full layout of a target quantum
circuit is desirable. Among other things, I will (1) present Qalypso, a
quantum datapath architecture that optimizes ancilla generation, (2)
discuss the design of routeable teleportation networks, (3) show how a
simple error-correction optimization based circuit retiming can improve
ADCR by an order of magnitude or more. This later optimization can
produce circuits of greater reliability by removing error correction steps.


John Kubiatowicz is a Professor of EECS at the University of California
at Berkeley. Prof. Kubiatowicz received a dual B.S in Physics and
Electrical Engineering (1987), as well as an MS in EECS (1993) and PhD
in EECS (1998), all from MIT. Kubiatowicz was chosen as one of
Scientific American’s top 50 researchers in 2002, one of US News and
World Report’s “people to watch for 2004″, and is the recipient of an
NSF PCASE award (2000). Kubiatowicz’s research interests include quantum
computing design tools and architectures, manycore Operating Systems
architecture and resource management, multiprocessor and manycore CPU
designs, Internet-scale distributed systems, and long-term digital
information preservation.