In the quest of completely describing entanglement in the general case of a finite number of parties sharing a physical system of finite dimensional Hilbert space a new entanglement magnitude isâ€¦ (More)

The optimal and minimal measuring strategy is obtained for a two-state system prepared in a mixed state with a probability given by any isotropic a priori distribution. We explicitly construct theâ€¦ (More)

In this paper we analyze the canonical forms into which any pure three-qubit state can be cast. The minimal forms, i.e. the ones with the minimal number of product states built from local bases, areâ€¦ (More)

We present optimal measuring strategies for the estimation of the entanglement of unknown two-qubit pure states and of the degree of mixing of unknown single-qubit mixed states, of which N identicalâ€¦ (More)

We critically analyze the introduction of an independent zero momentum mode field renormalization for Ï† 4. It leads to an infrared divergent effective action. It does not achieve its purpose:â€¦ (More)

We show how to decompose any density matrix of the simplest binary composite systems, whether separable or not, in terms of only product vectors. We determine for all cases the minimal number ofâ€¦ (More)

tes ). Entanglement is an essential ingredient in most app cations of quantum information. It arises when the sta of a multiparticle system is nonseparable; that is, when cannot be prepared locallyâ€¦ (More)

to Measurements disclose unknown information. The should disclose as much information as possible by us the least amount of physical resources. We present he for the first time, the most efficientâ€¦ (More)

Some quantum mechanical potentials, singular at short distances, lead to ultraviolet divergences when used in perturbation theory. Exactly as in quantum field theory, but much simpler, regularizationâ€¦ (More)

The general four parameter point interaction in one dimensional quantum mechanics is regulated. It allows the exact solution, but not the perturbative one. We conjecture that this is due to theâ€¦ (More)