We review recent experimental and theoretical work on ultrasmall metallic grains, ie grains
sufficiently small that the conduction electron energy spectrum becomes discrete. The …

We review recent experimental and theoretical work on superconductivity in ultrasmall
metallic grains, ie grains sufficiently small that the conduction electron energy spectrum …

A systematic comparison is conducted for pairing properties of finite systems at nonzero
temperature as predicted by the exact solutions of the pairing problem embedded in three …

We investigate how the interplay of quantum confinement and level broadening caused by
disorder affects superconducting correlations in ultra-small metallic grains. We use the …

The variation after projection approach is applied for the first time to the Richardson pairing
Hamiltonian to describe the thermodynamics of small superconductors with a fixed number …

The properties of general non-additive entropic forms and their emergence in quantum
statistical mechanics are discussed. As particular examples, we analyze the entropies …

We evaluate the exact concurrence between any two spins in a cyclic XX chain of n spins
placed in a uniform transverse magnetic field, at both zero and finite temperature, by means …

We discuss the application of the static path plus random-phase approximation (SPA+ RPA)
and the ensuing mean field+ RPA treatment to the evaluation of entanglement in composite …

In this paper, we have taken the effect of small size of nucleus and static fluctuations into
account in the Bardeen-Cooper-Schrieffer (BCS) theory of superconductivity calculations of …

A rigorous treatment of the combined effect of thermal and quantum fluctuations in a zero-
dimensional superconductor is considered one of the most relevant and still-unsolved …