27 citations · 80 across the 10 of their papers we have counts for
12 papers
Generalized evolution semigroups and general dichotomies
Nicolae Lupa, Liviu Horia Popescu
We introduce a special class of real semiflows, which is used to define a general type of evolution semigroups, associated to not necessarily exponentially bounded evolution famili…
Admissibility and general dichotomies for evolution families
Davor Dragicevic, Nevena Jurcevic Pecek, Nicolae Lupa
For an arbitrary noninvertible evolution family on the half-line and for in a large class of rate functions, we consider the notion of a -di…
A complete characterization of exponential stability for discrete dynamics
Nicolae Lupa, Liviu Horia Popescu
For a discrete dynamics defined by a sequence of bounded and not necessarily invertible linear operators, we give a complete characterization of exponential stability in terms of i…
Admissible Banach function spaces and nonuniform stabilities
Nicolae Lupa, Liviu Horia Popescu
For nonuniform exponentially bounded evolution families defined on Banach spaces, we introduce a class of Banach function spaces, whose norms are completely determined by the nonun…
Admissible Banach function spaces for linear dynamics with nonuniform behavior on the half-line
Nicolae Lupa, Liviu Horia Popescu
For nonuniform exponentially bounded evolution families on the half-line we introduce a class of Banach function spaces on which we define nonuniform evolution semigroups. We compl…
Dilations on locally Hilbert spaces
Dumitru Gaşpar, Păstorel Gaşpar, Nicolae Lupa
The principal theorem of Sz.-Nagy on dilation of a positive definite Hilbert space operator valued function has played a central role in the development of the non-self-adjoint ope…
Thresholds for reduction-related entanglement criteria in quantum information theory
Maria Anastasia Jivulescu, Nicolae Lupa, Ion Nechita
We consider random bipartite quantum states obtained by tracing out one subsystem from a random, uniformly distributed, tripartite pure quantum state. We compute thresholds for the…
Positive reduction from spectra
Maria Anastasia Jivulescu, Nicolae Lupa, Ion Nechita +1
We study the problem of whether all bipartite quantum states having a prescribed spectrum remain positive under the reduction map applied to one subsystem. We provide necessary and…
Integral conditions for nonuniform -dichotomy on the half-line
António J. G. Bento, Nicolae Lupa, Mihail Megan +1
We give necessary integral conditions and sufficient ones for the existence of a general concept of -dichotomy for evolution operators defined on the half-line which includes as…
On the reduction criterion for random quantum states
Maria Anastasia Jivulescu, Nicolae Lupa, Ion Nechita
In this paper we study the reduction criterion for detecting entanglement of large dimensional bipartite quantum systems. We first obtain an explicit formula for the moments of a r…
Exponential dichotomies of evolution operators in Banach spaces
Nicolae Lupa, Mihail Megan
This paper considers three dichotomy concepts (exponential dichotomy, uniform exponential dichotomy and strong exponential dichotomy) in the general context of non-invertible evolu…
Necessary and sufficient conditions for weak exponential instability of evolution operators
Nicolae Lupa
In this paper we give some necessary and sufficient characterizations for weak exponential instability of evolution operators. Variants for the classical results due to Datko and L…