Conditional quantum dynamics with several observers

Quantum Theory Without Observers

The concept of`measurement' becomes so fuzzy on reeection that it is quite surprising to have it appearing in physical theory at the most fundamental level.. .. D]oes not any analysis of measurement require concepts more fundamental than measurement? And should not the fundamental theory be about these more fundamental concepts? (Bell 1981 1, page 117])

Quantum Dynamics as an analog of Conditional Probability

Quantum theory can be regarded as a non-commutative generalization of classical probability. From this point of view, one expects quantum dynamics to be analogous to classical conditional probabilities. In this paper, a variant of the well-known isomorphism between completely positive maps and bipartite density operators is derived, which makes this connection much more explicit. The new isomor...

Quantum Conditional Probabilities Are Not Probabilities of Quantum Conditional

Conditional phase gate and quantum state transfer via off-resonant quantum Zeno dynamics

We propose a scheme to realize the conditional phase gate (CPG) and quantum state transfer (QST) between two qubits (acted by nitrogen-vacancy (NV) centers) based on off-resonant quantum Zeno dynamics. We also consider the entanglement dynamics of two qubits in this system. Since no cavity photons or excited levels of the NV center is populated during the whole process, the scheme is immune to ...

Quantum conditional query complexity

We define and study a new type of quantum oracle, the quantum conditional oracle, which provides oracle access to the conditional probabilities associatedwith an underlying distribution. Amongst other properties, we (a) obtain speed-ups over the best known quantum algorithms for identity testing, equivalence testing and uniformity testing of probability distributions; (b) study the power of the...