On Howland time-independent formulation of CP-divisible quantum evolutions

Superpositions of time evolutions of a quantum system and a quantum time-translation machine.

Discording power of quantum evolutions.

We introduce the discording power of a unitary transformation, which assesses its capability to produce quantum discord, and analyze in detail the generation of discord by relevant classes of two-qubit gates. Our measure is based on the Cartan decomposition of two-qubit unitaries and on evaluating the maximum discord achievable by a unitary upon acting on classical-classical states at fixed pur...

Quantum measurements in continuous time, non-Markovian evolutions and feedback.

In this article, we reconsider a version of quantum trajectory theory based on the stochastic Schrödinger equation with stochastic coefficients, which was mathematically introduced in the 1990s, and we develop it in order to describe the non-Markovian evolution of a quantum system continuously measured and controlled, thanks to a measurement-based feedback. Indeed, realistic descriptions of a f...

On a Time Symmetric Formulation of Quantum Mechanics

We explore further the suggestion to describe a preand post-selected system by a two-state, which is determined by two conditions. Starting with a formal definition of a two-state Hilbert space and basic operations, we systematically recast the basics of quantum mechanics dynamics, observables, and measurement theory in terms of two-states as the elementary quantities. We find a simple and sugg...

Controlled quantum evolutions and transitions

We study the nonstationary solutions of Fokker–Planck equations associated to either stationary or non stationary quantum states. In particular, we discuss the stationary states of quantum systems with singular velocity fields. We introduce a technique that allows arbitrary evolutions ruled by these equations to account for controlled quantum transitions. As a first signficant application we pr...