
Introduction
Objectives and Goals
Sponsorship


At the W. M. Keck Foundation Center for Extreme Quantum Information
Theory (xQIT) at the Massachusetts Institute of Technology (MIT),
we investigate information processing at the extreme limits posed
by the laws of physics. Our objective is to devise the new quantum
algorithms and protocols needed to approach the ultimate performance
bounds of quantum information systems.
Existing technologies for these applications are currently reaching
bounds set by quantum mechanics, that is, the standard quantum limits
that constrain the performance of conventional systems. Theory and
some proof of principle experiments have already shown that standard
quantum limits do not represent the ultimate capabilities that might
be achieved with novel system designs which make informed use of
quantummechanical properties.
If we succeed, we will have uncovered the fundamental physical limits
to computation, communication, and precision measurement.
The overarching objective of xQIT is to solve—or make significant
progress toward solving—three interrelated theoretical problems
in extreme quantum information:
 Solving averagecase NPcomplete problems.
 Deriving capacities
and coding techniques for quantum communication channels.
 Obtaining
fundamental physical limits to quantum sensing and control.
Each of these problems has the potential for significant impact
on society:
 NPcomplete problems encompass the bulk of outstanding problems
in optimization. Examples include optimization tasks arising in communication
networks, computer design, financial structures and portfolio management,
drug design, and allocation of public resources, to name just a few.
Enormous societal benefits would accrue, should solutions to these
problems become possible with quantum computers.
 All communication channels—including those associated with
fiberoptic, wireless, and satellite technologies—are, at
bottom, quantum mechanical, and existing optical communication systems
are already pushing up against quantummechanical bounds, i.e., the
standard quantum limits. Standard quantum limits, however, do not
represent the ultimate capabilities that might be achieved, because
conventional communication systems do not exploit "weird" quantum
features like entanglement. So, if we are to reap the full harvest
of the ongoing information processing revolution based on digital
computation and communication, we must derive the ultimate quantumlimited
capacities of such channels and develop coding techniques for attaining
those capacities.
 The rapid increase in computer power and the development of
precision measurement technologies such as GPS rely crucially on
technologies for fabrication, sensing, and control, and these too
are reaching their standard quantum limits. Whether it be to improve
the lithographic techniques used to make microprocessors or to
enhance the atomic clocks on which GPS relies, we need to break
the bonds of conventional thinking to reach truly fundamental limits
on fabrication, sensing, and control by using all the special properties
that quantum mechanics affords. For example, theory has already
shown that entanglement can, in principle, greatly increase the
accuracy of a variety of precision measurement systems. So, if
we are to maintain the rapid advance of precision measurement technologies
for a wealth of sensing and control applications, we must identify
the fundamental performance bounds that quantum mechanics imposes
on such systems, and we must develop procedures for attaining those
bounds.
The preceding three problems lie at the core of quantum information
theory. If one or more of them can be solved, then quantum information
will have made a great societal contribution. Note that these problems
are theoretical, not experimental. If theorists can solve one or
more of them, it will make the need for quantum computing and quantum
communication technology far more compelling than it is today, and
will therefore spur government and industry to major investments
in developing these technologies.
xQIT was formed in January 2007 with $1.63M in funding from the
W. M. Keck Foundation, with equivalent matching resources from MIT.
The W.M. Keck Foundation was established in 1954 in Los Angeles,
California by William Myron Keck, founder of The Superior Oil Company.
The Foundation is one of the nation's largest philanthropic organizations,
with assets of more than $1 billion. The Foundation's Science and
Engineering Program makes awards with the objective of supporting
innovative undergraduate instruction in these fields, as well as
leading university research programs and interdisciplinary projects.
From these founding resources, we expect to expand our diversity
of sponsorship to strengthen our research efforts on the fundamental
quantum theory problems that are the focus of xQIT.


"The
Keck Foundation has a distinguished history of supporting bold research
efforts and laying the groundwork at pivotal moments to enable breakthrough
scientific progress."
—Susan Hockfield,
President of MIT
