A Fundamental Property of Quantum-Mechanical Entropy

The information entropy of quantum mechanical states

– It is well known that a Shannon based definition of information entropy leads in the classical case to the Boltzmann entropy. It is tempting to regard the Von Neumann entropy as the corresponding quantummechanical definition. But the latter is problematic from quantum information point of view. Consequently we introduce a new definition of entropy that reflects the inherent uncertainty of qua...

Coherent Control of Quantum Entropy via Quantum Interference in a Four-Level Atomic System

The time evaluation of quantum entropy in a four-level double- type atomic system is theoretically investigated. Quantum entanglement of the atom and its spontaneous emission fields is then discussed via quantum entropy. It is found that the degree of entanglement can be increased by the quantum interference induced by spontaneous emission. The phase dependence of the atom-field entanglement is...

A Property of Free Entropy

Denote by Mk the algebra of complex k × k matrices, and by τk the normalized trace on Mk, i.e., τk(A) = 1 kTr(A) for A ∈ Mk. Consider for each k a standard Gaussian Hermitian random matrix Xk. Thus, if E denotes expected value, Eτk(Xk) = 0 and Eτk(X k) = 1. It was shown by E. Wigner [9] that, as k → ∞, Xk tends in distribution to a semicircular law, i.e., the limits μp = lim k→∞ Eτk(X p k) exis...

coherent control of quantum entropy via quantum interference in a four-level atomic system

the time evaluation of quantum entropy in a four-level double- type atomic system is theoretically investigated. quantum entanglement of the atom and its spontaneous emission fields is then discussed via quantum entropy. it is found that the degree of entanglement can be increased by the quantum interference induced by spontaneous emission. the phase dependence of the atom-field entanglement is...

A fundamental view of enthalpy–entropy compensation