Thanks to the large number of levels which can be coherently manipulated, molecular spin systems constitute a very promising platform for quantum computing. Indeed, they can embed quantum error correction within single molecular objects, thus greatly simplifying its actual realization in the short term. We consider a recent proposal, which exploits a spin qudit to encode the protected unit, and is tailored to fight pure dephasing. Here we compare the implementation of this code on different molecules, in which the qudit is provided by either an electronic or a nuclear spin (S, I > 1), coupled to a spin-1/2 electronic ancilla for error detection. By thorough numerical simulations we show that a significant gain in the effective phase memory time can be achieved. This is further enhanced by exploiting pulse-shaping techniques to reduce the leakage and/or the impact of decoherence during correction. Moreover, we simulate the implementation of single-qubit operations on the encoded states.

Quantum systems displaying many accessible levels could be very powerful units of forthcoming quantum computing architectures. Indeed, the large number of available states could significantly simplify the actual implementation of several algorithms. Here we show that artificial molecular spins are particularly suitable to realize such a platform. In particular, multispin molecules with competing interactions provide a large number of low-energy multiplets in which decoherence is strongly suppressed compared to a single spin $S$ and does not increase with the system size. This feature, combined with the proper connectivity between the multiplets, enables the implementation of complex operations with remarkable fidelity, thus fully unleashing the potential of the molecular approach. We demonstrate the power of this approach by numerically simulating the implementation of one- and two-qudit gates on realistic molecular systems.

Magnetic molecules are prototypical systems to investigate peculiar quantum mechanical phenomena. As such, simulating their static and dynamical behavior is intrinsically difficult for a classical computer, due to the exponential increase of required resources with the system size. Quantum computers solve this issue by providing an inherently quantum platform, suited to describe these magnetic systems. Here, we show that both the ground state properties and the spin dynamics of magnetic molecules can be simulated on prototype quantum computers, based on superconducting qubits. In particular, we study small-size anti-ferromagnetic spin chains and rings, which are ideal test-beds for these pioneering devices. We use the variational quantum eigensolver algorithm to determine the ground state wave-function with targeted ansatzes fulfilling the spin symmetries of the investigated models. The coherent spin dynamics are simulated by computing dynamical correlation functions, an essential ingredient to extract many experimentally accessible properties, such as the inelastic neutron cross-section.

Background: Short term increases in air pollution aggravate pre-existing respiratory diseases, increasing hospital admissions and leading to reduction of life expectancy in some subjects. Recently, attention has been directed to smaller particles (UFPs < 100 nm). Aim: The aim of this study is to disclose the pulmonary short-term effects induced by UFPs derived from two different anthropogenic sources (DEP, diesel exhaust particles; BC, biomass combustion derived particles). Methods: Male BALB/c mice were submitted to intratracheal instillation of 50 µg of BC or DEP in 100 µl of isotonic saline solution or 100 µl of isotonic saline solution (sham) by means of MicroSprayer® Aerosolizer system (Penn Century). After 3h, mice have been euthanized; Broncho Alveolar Lavage fluid (BALf) pellets and supernatants have been collected, and lungs were homogenated. Different pro-inflammatory, cytotoxic and oxidative stress markers have been analysed using biochemical methods such as total and differential cell counts, EF-SDS-PAGE and immunodecoration with specific antibodies, Luminex and colorimetric assays. Results: In the BALf, DEP treatment induced a significant increase in total cells count and PMNs %, while AMs % decreased. Moreover, total protein and ET-1 concentrations were higher in BALf after DEP treatment, comparing to sham. Finally, LDH activity resulted induced by BC and DEP treatment, and also MPO levels were increased by both BC and DEP. In lung parenchyma, DEP induced increased levels of HO-1, Cyp1b1 and COX2, while BC was not influent. Conclusions: DEP is more harmful than BC in inducing inflammation and oxidative stress after a single instillation in BALB/c mice, while both UFPs were equally cytotoxic.