Dear Quanta
On Monday Andrew Childs will speak and he will be around all day. He will not be here on
Tuesday. On Tuesday there is a seminar at 11 which I want to attend and might be of
interest to many of you. I suggest we not have our group meeting since it conflicts with
this talk. The following Tuesday is in MIT's spring break so we will not meet then
but we will meet after that.
Best,
Eddie
Tuesday, March 15; 11am, Duboc Seminar Room (4-331)
Hard Condensed Matter faculty candidate
Tzu-Chieh Wei (University of British Columbia)
“Valence-bond ground states of isotropic quantum antiferromagnetsfor universal quantum
computation”
The study of quantum spin systems dates back to the early twentieth century and has been
an active research field. Quantum computation, on the other hand, is a relatively new
research field, of less than three decades of age. In our work, we establish a new
connection between the two fields, by showing that a ground state of an isotropic quantum
antiferromagnetcan be used as a resource for universal quantum computation by measurement
on the quantum state. Such measurement-based quantum computation utilizes an initial
entangled resource state and proceeds with subsequent single-spin measurements only.
However, there were not many known resource states and it was actually shown that they are
a rarity.Recent quests for such computational resource states have turned to ground states
of short-ranged, preferably two-body, interacting Hamiltonians. In particular, success has
been obtained in the family of the Affleck-Kennedy-Lieb-Tasaki (AKLT) isotropic quantum
magnet models, in which single quantum-bit operations were shown to be possible. However,
single-qubitoperations are not enough, and it remained open whether any state in the AKLT
family can indeed provide the full capability for universal quantum computation. In this
talk, we shall demonstrate that the particular two-dimensional spin-3/2 AKLT state on the
honeycomb lattice, known to be a quantum disordered ground state without Neel order, does
enable universal quantum computation. Interestingly, this state was constructed not long
after the notion of quantum computation started to develop.
:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
Edward Farhi
Cecil and Ida Green Professor of Physics
Director
Center for Theoretical Physics
6-300
Massachusetts Institute of Technology
Cambridge MA 02139
617 253 4871
:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
_______________________________________________
qip mailing list
qip(a)mit.edu
http://mailman.mit.edu/mailman/listinfo/qip