[QIP-Sem] MIT Quantum Information Processing Seminar Reminder

[QIP-Sem Mailing List]

This week's MIT QIP seminar will take place on Monday, April 5th at 
16:00 in 4-237, and features:


Localizable Entanglement and Valence Bond States

by Ignacio Cirac (Max Planck Institute fuer Quantumoptik, Garching, Germany)

ABSTRACT

Much of the current effort in Quantum Information Theory is devoted 
to the description and quantification of the entanglement contained 
in quantum states, since this intriguing property of Quantum 
Mechanics is the basic resource of most of the applications in this 
field, including quantum communication and computation. In this talk 
I will introduce a new notion of entanglement which captures the idea 
of how this property can be localized in small subsystems by 
performing measurement in the rest of the system. I will also show 
how this notion allows to detect hidden orders in spin systems at 
zero temperature, and how it behaves in quantum phase transitions. 
Finally, I will show how these ideas may help to develop simulation 
schemes for spin chains and lattices.


There will also be a special seminar this week on Tuesday, April 6 
from 10:00 thru 11:00 AM in the Marlar Lounge (37-252)


Ion Trapology for Scalable Quantum Information Processing

by David J. Wineland (Time & Frequency Division, NIST, Boulder CO)

ABSTRACT

At NIST, by using a few trapped atomic ions, we have been able to 
implement the basic one- and two-qubit gate operations required for 
quantum information processing [1].  The challenge is to scale up 
this system in order to perform large-scale processing.  One way this 
might be accomplished is to use an array of ion trap zones, each of 
which contains a small number of ions - to facilitate efficient 
gates.  By shuttling ions between zones, gates between selected ions 
in the array could be achieved [2].  By separating ions contained in 
one trap, moving them to separate trap zones, and performing 
subsequent logic operations, we can now implement the basic steps of 
this scheme.  However, we now face significant practical problems in 
how to actually fabricate the required large trap structures, how to 
wire up the trap electrodes and control their potentials, and how to 
produce and manipulate the many laser beams that will be needed in 
such a device.  These and other issues will be discussed.

[1] "The physical implementation of quantum computation",  D. P. 
DiVincenzo, in Scalable Quantum Computers, ed. by S. L. Braunstein 
and H. K. Lo (Wiley-VCH, Berlin, 2001), pp. 1-13.
[2] "Architecture for a large-scale ion-trap quantum computer",  D. 
Kielpinski, C. Monroe, and D. J. Wineland, Nature 417, 709-711 (2002).
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