Quantum Lunch Location:
T-Division Conference Room, TA-3,
Building 123, Room 121
Quantum Institute: Visitor Schedule
The Quantum Lunch is regularly held on Thursdays in the Theoretical Division Conference Room, TA-3, Building 123, Room 121.
For more information, contact Diego Dalvit.
January 25, 2007
Distinguished Quantum States
Hilbert space is a big place. Therefore, it is often convenient, and
illuminating, to define sets of distinguished quantum states:
(generalized) coherent states, minimum uncertainty states, pointer
states, decoherence free subspaces and noiseless subsystems. These
different sets of states are defined in different ways, and for
different reasons, but they are often intimately related.
In this talk, I will argue that minimum uncertainty states are best
understood from the point of Fisher information. Their relation with
generalized coherent states is well known. On the other hand,
identifying generalized coherent states with pointer states requires,
in general, a higher degree of symmetry than in the particular case of
field coherent states. Finally, while the relation of all of the above
with decoherence free subspaces is rather transparent, the relation
with noiseless subsystems turns out to be somewhat more problematic.