Mariela Portesi

Some extensions of the uncertainty principle

We study the formulation of the uncertainty principle in quantum mechanics in terms of entropic inequalities, extending results recently derived by Bialynicki-Birula [I. Bialynicki-Birula, Formulation of the uncertainty relations in terms of the Renyi entropies, Physical Review A 74 (5) (2006) 052101] and Zozor et al. [S. Zozor, C. Vignat, On classes of non-Gaussian asymptotic minimizers in entropic uncertainty principles, Physica A 375 (2) (2007) 499–517]. Those inequalities can be considered as generalizations of the Heisenberg uncertainty principle, since they measure the mutual uncertainty of a wave function and its Fourier transform through their associated Renyi entropies with conjugated indices. We consider here the general case where the entropic indices are not conjugated, in both cases where the state space is discrete and continuous: we discuss the existence of an uncertainty inequality depending on the location of the entropic indices α and β in the plane (α,β). Our results explain and extend a recent study by Luis [A. Luis, Quantum properties of exponential states, Physical Review A 75 (2007) 052115], where states with quantum fluctuations below the Gaussian case are discussed at the single point (2,2).

Generalized entropy as a measure of quantum uncertainty

A generalized entropy is used in order to advance a different form of expressing the Uncertainty Principle of Quantum mechanics. We consider the generalized entropic formulation for different pairs of incompatible observables. In particular, we study the number-phase entropic uncertainty measure for the case of coherent states within the Pegg-Barnett theory. We also tackle the situation of operators with continuous spectra, where a correlation functional is calculated in terms of generalized joint and marginal entropies, for harmonic oscillator wavefunctions.

A family of generalized quantum entropies: definition and properties

We present a quantum version of the generalized

Information measures based on Tsallis’ entropy and geometric considerations for thermodynamic systems

(h,\phi )

On a generalized entropic uncertainty relation in the case of the qubit

(h,ϕ)-entropies, introduced by Salicrú et al. for the study of classical probability distributions. We establish their basic properties and show that already known quantum entropies such as von Neumann, and quantum versions of Rényi, Tsallis, and unified entropies, constitute particular classes of the present general quantum Salicrú form. We exhibit that majorization plays a key role in explaining most of their common features. We give a characterization of the quantum

Position-momentum uncertainty relation based on power moments of arbitrary order

(h,\phi )