# Quantum Computation/Cryptography at Los Alamos

"Where a calculator on the Eniac is equipped with 18000 vacuum tubes
and weighs 30 tons, computers in the future may have only 1000 tubes
and weigh only 1 1/2 tons"

Popular Mechanics, March 1949

This Homepage will give you an overview of the work done at Los Alamos
on Quantum Computation and Cryptography as well as related links.

The idea of quantum computation and cryptography is to use
the laws of quantum mechanics for either computing or exchange
secrets messages. Using quantum mechanics instead of classical mechanics
has huge advantages but also some drawbacks. Quantum mechanics makes the applications much more powerful but at the same time much more fragile
against noise. To learn more about this browse around!

Overview of achievements in T6-CIC3 groups
People doing Quantum Computation/Cryptography at Los Alamos

Theory at Los Alamos

Experiments at Los Alamos

List of Seminars on Quantum Computation in Los Alamos and Worlwide Conferences

Proceedings of the
Quantum Coherence and Decoherence, Santa-Barbara, Dec 15-18, 1996.

## New - New - New

Experimental Quantum
Error Correction (or pdf) Quantum error correction is required to
compensate for the fragility of the state of a quantum computer. We
report the first experimental implementations of quantum error
correction and confirm the expected state stabilization. A precise
study of the decay behavior is studied in alanine and a full
implemetation of error correction protocol is implemented in
trichloroethylene. In NMR computing, however, a net improvement in
the signal-to-noise would require very high polarization. The
experiment implemented the 3-bit code for phase errors in liquid state
state NMR.

Quantum Teleportation
(or pdf).
Quantum mechanics provides spectacular new information
processing abilities. One of the most
unexpected is a procedure called *quantum teleportation*
suggested by Bennet
et al.
that allows the quantum state of a system to be transported from one
location to another, without moving through the intervening space. We
have implemented the full quantum teleportation operation over
inter-atomic distances using liquid state nuclear magnetic resonance
(NMR). The inclusion of the final stage enables for the first time a
teleportation implementation which may be used as a
* subroutine * in larger quantum computations, or for quantum
communication. Our experiment also demonstrates the use of
* quantum process tomography *, a procedure to completely
characterize the dynamics of a quantum system. Finally, we
demonstrate a controlled exploitation of decoherence as a tool to
assist in the performance of an experiment.

Dilbert and Quantum Computation