Dynamics of Quantum Noise in a Tunnel Junction under ac Excitation

We report the first measurement of the \emph{dynamical response} of shot noise (measured at frequency $\omega$) of a tunnel junction to an ac excitation at frequency $\omega_0$. The experiment is performed in the quantum regime, $\hbar\omega\sim\hbar\omega_0\gg k_BT$ at very low temperature T=35mK and high frequency $\omega_0/2\pi=6.2$ GHz. We observe that the noise responds in phase with the excitation, but not adiabatically. The results are in very good agreement with a prediction based on a new current-current correlator.Comment: Theory removed. More experimental details. One extra figur

Locally principal ideals and finite character

It is well-known that if R is a domain with finite character, each locally principal nonzero ideal of R is invertible. We address the problem of understanding when the converse is true and survey some recent results

Stability and Clifford regularity with respect to star operations

In the last few years, the concepts of stability and Clifford regularity have been fruitfully extended by using star operations. In this paper we deepen the study of star stable and star regular domains and relate these two classes of domains to each other.Comment: 22 pages; Comm. Alg., 201

Star Stable Domains

We introduce and study the notion of $\star$-stability with respect to a semistar operation $\star$ defined on a domain $R$; in particular we consider the case where $\star$ is the $w$-operation. This notion allows us to generalize and improve several properties of stable domains and totally divisorial domains.Comment: 21 pages. J. Pure Appl. Algebra, to appea

Star Stability and Star Regularity for Mori Domains

In the last few years, the concepts of stability and Clifford regularity have been fruitfully extended by using star operations. In this paper we study and put in relation these properties for Noetherian and Mori domains, substantially improving several results present in the literature.Comment: 14 pages; Rend. Semin. Mat. Univ. Padova, 201