TY - JOUR
T1 - Pre- and postselected quantum states
T2 - Density matrices, tomography, and Kraus operators
AU - Popescu, Sandu
AU - Silva, Ralph F
AU - Guryanova, Yelena A
AU - Brunner, Nicolas
AU - Linden, Noah
AU - Short, A J
PY - 2014/1/23
Y1 - 2014/1/23
N2 - We present a general formalism for characterizing 2-time quantum states, describing pre- and postselected quantum systems. The most general 2-time state is characterized by a "density vector" that is independent of measurements performed between the preparation and postselection. We provide a method for performing tomography of an unknown 2-time density vector. This procedure, which cannot be implemented by weak or projective measurements, brings new insight to the fundamental role played by Kraus operators in quantum measurements. Finally, after showing that general states and measurements are isomorphic, we show that any measurement on a 2-time state can be mapped to a measurement on a preselected bipartite state
AB - We present a general formalism for characterizing 2-time quantum states, describing pre- and postselected quantum systems. The most general 2-time state is characterized by a "density vector" that is independent of measurements performed between the preparation and postselection. We provide a method for performing tomography of an unknown 2-time density vector. This procedure, which cannot be implemented by weak or projective measurements, brings new insight to the fundamental role played by Kraus operators in quantum measurements. Finally, after showing that general states and measurements are isomorphic, we show that any measurement on a 2-time state can be mapped to a measurement on a preselected bipartite state
KW - quantum
KW - foundations
KW - pre and postselection
UR - http://www.scopus.com/inward/record.url?scp=84894460244&partnerID=8YFLogxK
U2 - 10.1103/PhysRevA.89.012121
DO - 10.1103/PhysRevA.89.012121
M3 - Article (Academic Journal)
AN - SCOPUS:84894460244
VL - 89
JO - Physical Review A: Atomic, Molecular and Optical Physics
JF - Physical Review A: Atomic, Molecular and Optical Physics
SN - 1050-2947
IS - 1
M1 - 012121
ER -
