59 research outputs found
On measurements of the canonical phase observable
Measurements of single-mode phase observables are studied in the spirit of
the quantum theory of measurement. We determine the minimal measurement models
of phase observables and consider methods of measuring such observables by
using a double homodyne detector. We show that, in principle, the canonical
phase distribution of the signal state can be measured via double homodyne
detection by first processing the state using a two-mode unitary channel.Comment: 22 pages, 2 figure
An attempt to understand relational quantum mechanics
We search for a possible mathematical formulation of some of the key ideas of
the relational interpretation of quantum mechanics and study their
consequences. We also briefly overview some proposals of relational quantum
mechanics for an axiomatic reconstruction of the Hilbert space formulation of
quantum mechanics
Generalized Coherent States and Extremal Positive Operator Valued Measures
We present a correspondence between positive operator valued measures (POVMs)
and sets of generalized coherent states. Positive operator valued measures
describe quantum observables and, similarly to quantum states, also quantum
observables can be mixed. We show how the formalism of generalized coherent
states leads to a useful characterization of extremal POVMs. We prove that
covariant phase space observables related to squeezed states are extremal,
while the ones related to number states are not extremal
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