Qubit positive-operator-valued measurements by destructive weak measurements

Positive Operator - Valued Measurements

Signatures of quantum behavior in single-qubit weak measurements.

With the recent surge of interest in quantum computation, it has become very important to develop clear experimental tests for "quantum behavior" in a system. This issue has been addressed in the past in the form of the inequalities due to Bell and those due to Leggett and Garg. These inequalities concern the results of ideal projective measurements, however, which are experimentally difficult ...

Weak Value and Weak Measurements

The weak value of a variable O is a description of an effective interaction with that variable in the limit of weak coupling. For a pre-and post-selected system described at time t by the two-state vector Φ| |Ψ (see entry Two-State Vector Formalism), the weak value is [1]: O w ≡ Φ|O|Ψ Φ|Ψ. (1) Contrary to classical physics, variables in quantum mechanics might not have definite values at a give...

Enhancing metrology sensitivity by weak measurements

Quantummechanics imposes strict limits on the precision attainable for various sets of measurements. Understanding the fundamental principles of these restrictions enables the realization of metrology schemes that can fully exploit available resources, resulting in significant improvement of both classical and quantum measurements. Quantum photonic resources can be employed for novel metrology ...

Non-statistical Weak Measurements

Non-statistical weak measurements yield weak values that are outside the range of eigenvalues and are not rare, suggesting that weak values are a property of every preand-post-selected ensemble. They also extend the applicability and valid regime of weak values.